Co-Sponsored by

China Agricultural University

An international symposium addressing global issues and trends in nutrient

management. e symposium focuses on how agricultural management

practices, technological advances, and global or regional policies are affecting

both nutrient use efficiency in the food chain and the quality of our

environment in different regions of the world.

August 21-24, 2011 University of Delaware

4th International SymposiumProceedings

GLOBAL ISSUES IN NUTRIENT MANAGEMENT SCIENCE, TECHNOLOGY AND POLICY 4TH INTERNATIONAL NUTRIENT MANAGEMENT SYMPOSIUM

AUGUST 21-24, 2011

UNIVERSITY OF DELAWARE, NEWARK, DELAWARE, USA

Welcome to the 4th International Nutrient Management Symposium! The Symposium Steering Committee appreciates your participation in what promises to be an outstanding international conference focusing on Global Issues in Nutrient Management Science, Technology and Policy. We are fortunate to have presentations by some of the leading nutrient management scientists in the world who will address the Symposium theme “…how agricultural management practices, technological advances, and global or regional policies are affecting both nutrient use efficiency in the food chain and the quality of our environment in different regions of the world”. A Keynote Panel will address one of the most important contemporary agri-environmental issues in the USA today – the nutrient management challenges and progress facing all who care about the Chesapeake Bay, a vital economic resource and national ecological treasure. Most importantly, Symposium participants will have numerous opportunities to engage in discussions and debate on a wide range of topics related to nutrient management science, technology, and policy. We hope that you find the Symposium presentations interesting and that you meet new colleagues and build friendships and professional partnerships which will contribute to truly worldwide efforts to manage nutrients efficiently, ensure food security, and improve environmental quality. Thank you again for joining us at the University of Delaware in 2011 at the 4th International Nutrient Management Symposium!

SYMPOSIUM STEERING COMMITTEE

DR. TOM SIMS COLLEGE OF AGRICULTURE & NATURAL RESOURCES UNIVERSITY OF DELAWARE

DR. OENE OENEMA WAGENINGEN UNIVERSITY & RESEARCH CENTER THE NETHERLANDS

DR. ZHENGXIA DOU SCHOOL OF VETERINARY MEDICINE UNIVERSITY OF PENNSYLVANIA

DR. JOSHUA MCGRATH COLLEGE OF AGRICULTURE & NATURAL RESOURCES UNIVERSITY OF MARYLAND

DR. FUSUO ZHANG COLLEGE OF RESOURCES & ENVIRONMENTAL SCIENCES CHINA AGRICULTURAL UNIVERSITY

DR. LIN MA COLLEGE OF RESOURCES & ENVIRONMENTAL SCIENCES CHINA AGRICULTURAL UNIVERSITY

DR. PETER KLEINMAN USDA AGRICULTURAL RESEARCH SERVICE PENNSYLVANIA STATE UNIVERSITY

SYMPOSIUM SUPPORT STAFF – UD COLLEGE OF AGRICULTURE & NATURAL RESOURCES

MARIA PAUTLER RACHAEL DUBINSKY

HANNAH WATERHOUSE SUDARSHAN DUTTA

2

Table of Contents p.

Speaker Biosketches 3-6

Symposium Agenda 7-10

Abstracts of Oral Presentations 11-36

Abstracts of Poster Presentations 37-59

*Posters will be displayed throughout the entire meeting

Authors presenting on Monday, August 22, 2011 38-47

Authors presenting on Tuesday, August 23, 2011 48-59

3

Speaker Biosketches

Plenary Speaker:

Oene Oenema has a BSc in agronomy, a MSc in soil science and plant nutrition and a PhD in marine geochemistry. He is an internationally recognized expert in the field of nutrient management and mitigation of greenhouse gas emissions. His extensive international experience includes projects in many European countries but also in China, Africa and America. Since 1994, he has been a professor in soil fertility and nutrient management at Wageningen University, teaching nutrient management and supervising PhD students. He is chairman of a scientific committee that advices the Ministries of Environment and Agriculture about the nutrient management policy in the Netherlands, and co-chair of the UN-ECE-CLRTAP Task Force on Reactive Nitrogen.

Keynote Speakers:

Fusuo Zhang is professor of plant nutrition and Dean of the College of Resources and Environmental Sciences at China Agricultural University, Beijing. He focuses on developing strategies and technologies for the optimization of plant nutrient use efficiency and increasing crop yield simultaneously. His work comprises dynamical monitoring of nutrient bio-availability in soil, plant-soil interactions (rhizosphere processes), real-time plant analyses and nutrient cycling assessments. He has a very comprehensive publication record in international journals (e.g. "Science", "PNAS") and has contributed to the overall improvement of environmental sustainability of plant production in China. Additionally, Zhang received many national and international prizes, including the "National Science Prize of State Council of China", the "International Crop Nutrition Award."

Anjan Datta has a Masters in Economics with Honours and a PhD in development studies. In 2002, he joined the United Nations Environment Programme as Programme Officer, and presently he leads the Secretariat of the Global Partnership on Nutrient Management (GPNM). Prior to joining UNEP, during 1976-2001, he worked with various research institutes, Universities, UN agencies, the World Bank, NGOs and bi-lateral donor agencies. Over the years he has been published extensively on land and water resources management. He is the author of three books, numerous articles for academic journals and edited books, and many research monographs.

4

Zhengxia Dou received her BS and MS degrees in chemistry and soil sciences in China, and PhD in soil sciences at Penn State University. Since 1994, she has been working at the University of Pennsylvania, School of Veterinary Medicine, with research focusing on integrated nutrient management in animal production systems.

Keynote Panel:

Jon Capacasa is the Director of the Water Protection Division for EPA Region III. In this capacity he directs the implementation of the Clean Water Act and Safe Drinking Water Act programs for the five Mid-Atlantic States plus the District of Columbia. He has worked to integrate over 20 water programs with a focus on innovative partnerships, measurable environmental results, and the Regional Healthy Waters priority.

Douglas B. Beegle is a distinguished professor of agronomy and extension soil fertility specialist in the department of crop and soil sciences at Penn State University. Beegle is very active in the state, regionally and nationally in working with farmers, farm organizations, ag industry, and government agencies to develop nutrient management programs that optimize nutrient management for crop and livestock production while at the same time minimizing the potential impact of nutrients on the environment. Beegle is a native of Pennsylvania and received his Ph.D. from Penn State in1983. He is a fellow of the Soil Science Society of America and the American Society of Agronomy and has received several regional and national awards for his work in nutrient management.

5

Ed Kee was confirmed by the Delaware Senate and sworn-in as Delaware‘s Secretary of Agriculture on January 22, 2009. Kee is a native Delawarean who was born in New Castle and now lives in Sussex County. He has spent his entire career in Delaware Agriculture. Kee began his professional agricultural career as the farm manager at Nassau Orchards in Lewes, Delaware. Kee was appointed the Kent County Agricultural Agent for the University of Delaware in 1978, and moved to State Vegetable Crops Specialist, working out of Georgetown. In 2004, Kee was appointed as the Extension Agricultural Program Leader. He served as the Vegetable Crop Specialist and the Ag Program Leader. Kee retired from the University in 2008 and worked for Hanover Foods

Corporation as Director of Agriculture. Kee is a nationally and internationally recognized expert on vegetable science. He has authored or co-authored more than 30 articles in peer-reviewed scholarly journals. These include articles published in the fields of horticulture, vegetable science, agricultural engineering, agricultural economics, history and civil rights.

Kevin G. Sellner, Executive Director, Chesapeake Research Consortium. As Consortium Executive Director, Sellner‘s primary role is to encourage active research programs across the six Consortium member institutions (www.chesapeake.org) and their extended partners from agencies, other institutions, and NGOs in the Chesapeake watershed focusing on fundamental basic and applied air, land, and water-related research to inform science-based management in the region. In general, he serves as a liaison between the scientific community and the Bay Program partners, providing recent research results for, ideally, consideration in restoration management and policies within the watershed jurisdictions. Sellner also teaches in the UMD Marine Estuarine Environmental Science program and is a plankton ecologist, with a primary focus on harmful algal blooms.

Jennifer Volk received both her undergraduate degree in chemistry and graduate degree in marine studies from the University of Delaware; she was the recipient of a graduate fellowship through the Delaware Water Resources Center. Volk began working in the Delaware Department of Natural Resources and Environmental Control‘s Watershed Assessment Section as an Environmental Scientist in 2003. She has assisted with the development of Total Maximum Daily Loads for nitrogen and phosphorus and has worked with stakeholder groups to identify strategies to reduce nonpoint source pollution. She is currently leading efforts to develop and implement a Watershed Implementation Plan in Delaware‘s portion of the Chesapeake Bay Watershed.

6

Keynote Speakers:

Peter Kleinman is a soil scientist with USDA-ARS‘s Pasture Systems and Watershed Management Research Unit in State College, Pennsylvania. Kleinman‘s program advances nutrient management to protect water quality. His applied research produces tools for farmers and scientists alike. His basic research examines the transport of nutrients across landscapes.

Xinping Chen is a professor in the College of Resources and Environmental Sciences, China Agricultural University. He received his PhD at the University of Hohenheim, Germany, in 2003. His research focuses on integrated nutrient management and integrated soil-crop systems management for improving crop productivity and nutrient use efficiency.

Phil Jordan is a Principal Scientist on the Agricultural Catchments Programme, Teagasc (Wexford, Ireland) and a faculty member in the School of Environmental Sciences, University of Ulster. He has degrees in geography and environmental science from the Universities of Leeds and Ulster and his research interests include the transport and fate of nutrients in terrestrial and aquatic systems.

Don Flaten is a professor in the department of soil science at the University of Manitoba, where he specializes in nutrient management teaching and research. Flaten has led or served as a co-investigator on several research projects and reports in the area of phosphorus-based manure management. He serves on the Lake Winnipeg Stewardship Board, the Manitoba Rural Adaptation Council and has also served on the Manitoba Phosphorus Expert Committee. Prior to joining the department of soil science on a full-time basis, Flaten was director of the School of Agriculture and an associate dean for the faculty of agricultural and food sciences.

7

GLOBAL ISSUES IN NUTRIENT MANAGEMENT SCIENCE, TECHNOLOGY AND POLICY 4TH INTERNATIONAL NUTRIENT MANAGEMENT SYMPOSIUM

AUGUST 21-24, 2011

UNIVERSITY OF DELAWARE, NEWARK, DELAWARE, USA

Sponsored by the University of Delaware College of Agriculture & Natural Resources,

China Agricultural University, Wageningen University, the University of Pennsylvania,

Delaware Environmental Institute and the University of Delaware Institute of Global Studies

SYMPOSIUM PROGRAM CLAYTON HALL, UNIVERSITY OF DELAWARE

Sunday, August 21st:

12–5 p.m. Registration and check-in

6-8 p.m. Welcome reception (with light refreshments)

Monday, August 22nd: [Moderator: Dr. Tom Sims, University of Delaware]

8:00 a.m. Plenary: Global Trends and Challenges in Nutrient Management

Dr. Oene Oenema, Wageningen University

8:30 Keynote: Managing Nutrients for Food Security and the Environment in

21st Century China

Dr. Fusuo Zhang, China Agricultural University

9:00 Keynote: Addressing the Nutrient Challenge: Role of the Global Partnership in

Nutrient Management in Promoting Sustainable Nutrient Management

Dr. Anjan Datta, United Nations Environment Program

9:30 Keynote: Nutrient Management Challenges in Africa: Nutrient Scarcity and Soil

Degradation Endanger Food Security

Dr. Zhengxia Dou, University of Pennsylvania

8

10:00 Break

10:30 Keynote Panel: Nutrient Management Challenges and Progress in the

Chesapeake Bay Watershed

Jon Capacasa, USEPA Region III Watershed Protection Division

Dr. Douglas Beegle, Pennsylvania State University

Edwin Kee, Delaware Department of Agriculture

Dr. Kevin Sellner, Chesapeake Research Consortium

Jennifer Volk, Delaware Department Natural Resources and Environmental

Control

Noon Lunch

Monday, August 22nd: [Moderator: Dr. Joshua McGrath, University of Maryland]

1:30 p.m. Keynote: Adopting Innovations through Collaborative Agricultural Research to

Improve Water Quality at Regional Scales

Dr. Peter Kleinman, USDA-ARS

2:00 Adaptive Management Strategies: Improving Nutrient Management at Farm and

Watershed Scales

Dr. Tom Morris, University of Connecticut

2:30 Nutrient Management Strategies for Dairy Based Agriculture

Dr. Quirine Ketterings, Cornell University

3:00 Legacy Phosphorus: Management Options for the Chesapeake Bay Watershed

Dr. Tom Sims, University of Delaware

3:30 Break

4:00-6:00 Poster presentations on best management practices and policies to optimize

agricultural nutrient use efficiency and reduce nutrient loss to water

6:30 Picnic Dinner (Townsend Hall, UD Botanic Gardens)

9

Tuesday, August 23rd: [Moderator: Dr. Zhengxia Dou, University of Pennsylvania]

8:00 a.m. Keynote: Advances in Nutrient Management for Major Crops in China

Dr. Xinping Chen, China Agricultural University

8:30 Nitrogen and Phosphorus Flows in the Food Chain and Their Contributions to

Non-Point Pollution in China

Dr. Wenqi Ma, Agricultural University of Hebei

9:00 Nutrient Management Policy in China: History, Current Status, Future Trends

Dr. Weifeng Zhang, China Agricultural University

9:30 Advances in Fertilizer Technologies for Improved Nutrient Management

Dr. Greg Binford, University of Delaware

10:00 Break

10:30 Keynote: Nutrient Management at the Catchment Scale: European Union Policy

Expectations in Ireland

Dr. Phil Jordan, Teagasc Agricultural Catchments Program

11:00 Managing Crop Nutrients Locally for Global Results with 4R Nutrient

Stewardship

Dr. Tom Bruulsema, International Plant Nutrition Institute

11:30 Managing Animal Manure Nutrients for Optimum Yields and Water Quality

Dr. Rory Maguire, Virginia Tech University

Noon Lunch

Tuesday, August 23rd: [Moderator: Dr. Peter Kleinman, USDA Agricultural Research Service]

1:30 p.m. Keynote: Canada’s Nutrient Management Challenges: Advances in Agricultural

Best Management Practices for Food Security and Water Quality

Dr. Don Flaten, University of Manitoba, Canada

2:00 Advances in Sensing Technologies to Improve Nutrient Management

Dr. Wade Thomason, Virginia Tech University

10

2:30 Managing Agricultural Drainage Waters to Protect Water Quality

Dr. Joshua McGrath, University of Maryland

3:00 Improving Nutrient Management by Advancing Irrigation Management

James Adkins, University of Delaware

3:30 Break

4:00-6:00 Poster presentations on best management practices and policies to optimize

agricultural nutrient use efficiency and reduce nutrient loss to water

6:30 Dinner (Clayton Hall)

Wednesday, August 24th:

8 a.m. to 8 p.m. Tour of the Chesapeake Bay Watershed, including field sites showing

nature and causes of agricultural problems and urban contributions and

innovative solutions to protect the Bay, and discussions with those

developing and implementing national, regional, and state level agri-

environmental policies (all day tour, returns to UD campus in Newark,

Delaware after dinner near Annapolis, Maryland).

NOTE: Post-Symposium Workshop on Advances in Rhizosphere Science

For details contact: Dr. Harsh Bais, University of Delaware (bais@dbi.udel.edu)

Thursday, August 25th:

9 a.m. to 4 p.m. Mini-workshop on Advances in Rhizosphere Science: Implications for Food

Security and Environmental Quality (Townsend Hall)

Co-Sponsored by: Delaware Environmental Institute, UD College of

Agriculture & Natural Resources, and China Agricultural University

11

Abstracts of Oral Presentations

12

Global Trends and Challenges in Nutrient Management Oene Oenema, Wageningen University,

P.O. Box 47, NL-6700 Wageningen, The Netherlands oene.oenema@wur.nl

Nutrient management is generally understood as ―the process of allocating and handling nutrient resources and flows to achieve societal objectives.‖ It is a dynamic and complex process as nutrient resources and flows, and societal objectives vary in space and time. Commonly, the societal objectives relate to the guarantee of sufficient and safe food, feed and fiber production, farm income, and low nutrient losses, which are not easily met simultaneously. Roughly one-third of the global human population suffers from temporary food shortages and nutrient deficiency, roughly two-third of the farmers suffer from low farm income, while many high-productive areas contribute to polluting groundwater, surface waters and natural terrestrial ecosystems with nutrients. Also, the demands for biofuel production are much larger than currently achieved, and easily accessible nutrient resources, especially phosphorus, are depleted within a few generations.

Nutrient management is generally implemented at field, farm and watershed levels, although not all countries are the same. For a long time the focus has been at field and farm levels, and nutrient management is seen primarily as a farmers‘ activity, as an activity of food producers. More recently, the watershed has been identified as the entity where water quality objectives have to be achieved, involving especially farmers and (waste) water managers. However, the questions remain whether the field, farm and watershed are the appropriate scales, whether farmers and (waste) water managers are the key nutrient managers, and also which societal objectives are being achieved then?

For sure, agriculture is by far the biggest user of nutrients, for producing food. Roughly 50% of the applied nutrients are withdrawn in harvested products, while the remainder accumulates in soil or dissipates into the wider environment. Less than half of the harvested products end up in food on the plate of consumers, while the remainder is recycled in agriculture and industry or dissipated into the environment. Further, less than 1% of the nutrients ingested are retained by humans and the remainder is excreted. Hence, the fraction of nutrients utilized ultimately depends on the human diet, on the whole food-production-processing-consumption chain.

Globalization strongly influences human diets and the food-production-processing-consumption chain. It leads to regional-specific specialization, intensification, up-scaling and re-localization of food and fiber production, because of location-specific cost advantages. A few transnational corporations and the retail sector increasingly dominate the food chain. Globalization leads to unprecedented changes in nutrient flows, which are not properly understood yet. These changes provide huge challenges for nutrient management, also in terms of defining appropriate objectives, stakeholders and scales.

13

Managing Nutrients for Food Security and the Environment in 21st Century China

Fusuo Zhang, Key Laboratory of Plant Nutrition, MOA, China Agricultural University, Beijing 100193, China;

Department of Plant Nutrition, China Agricultural University, Yuanmingyuan West Road 2, Beijing 100193, China zhangfs@cau.edu.cn

During the past 50 years, China has successfully realized the dream of food self-sufficiency, which is also a remarkable contribution to the world‘s food security. China has produced 20% of world cereals and 28% of world meats and feeds 22% of the global population with only 8% arable land. However, this was achieved by very high inputs such as fertilizers. China consumed 33% of world chemical fertilizer with much lower use efficiency and high environmental cost. In the 21st century, with the population peak in China and subsequent food demand increases, crop production must be increased until 2030. New challenges for agriculture sustainability and ecosystem services need to be stressed during the coming several decades in order to ensure food security and environmental quality at the same time, which can only be achieved by increasing crop productivity and improving nutrient use efficiency simultaneously. Here, we advocate and develop Integrated Soil-crop System Management (ISSM). In this approach, the key points are to (1) take all possible soil quality improvement measures into consideration, (2) integrate the utilization of various nutrient resources and match nutrient supply to crop requirements, and (3) integrate soil and nutrient management with high yielding cultivation systems. Recent field experiments have shed light on how ISSM can lead to significant increases in crop yields while increasing N use efficiency and reducing environmental risk. The results of the NUFER model show that by using ISSM and improving manure management, the chemical N and P fertilizer consumption decreased by 11% and 17%, N and P losses decreased by 21% and 34%, while N and P use efficiencies in food chain increased by 73% and 89% respectively at the national level. Key words: food security, ISSM, nutrient management

14

Addressing the Nutrient Challenge: Role of the Global Partnership in Nutrient Management in Promoting Sustainable Nutrient

Management

Anjan Datta, United Nations Environment Program, anjan.datta@unep.org

The presentation will elucidate the nature and complexity of the ―nutrient challenge‖ by drawing examples and evidences and explaining how the Global Partnership on Nutrient Management (GPNM) views the ―nutrient challenge‖ and what actions it advocates to promote effective nutrient management to minimize negative impacts on the environment and human health, while maximizing their contribution to global sustainable development and poverty reduction. Nutrients: nitrogen and phosphorous are key to growing crops and thus to the world‘s food security. However, in some parts of the world farmers do not have access to enough nutrients to grow crops and feed growing populations, while in many other parts of the world there is an ‗excess‘ of them in the environment as a result of industrial and agricultural activity. These nutrients have profound impacts, from pollution of water supplies, creation of dead zones to the undermining of important ecosystems and the services and livelihoods they support. The result is a seeming divide between societal needs for food and energy and a complex web of adverse environmental impacts which undermine the natural resource base and the services and livelihoods it provides. This divide -‗the nutrient challenge‘- is set to intensify, to the cost of countries, as population, urbanization and food and energy demands increase. If the ―nutrient challenge‖ is to be met, it will be important to show that greater efficiency in fertilizer use is an important part of meeting sustainable food security, including areas of overall nutrient shortage. The GPNM has been launched to answer this challenge. The GPNM is a global partnership of governments, scientists, policy makers, private sector, NGOs and international organizations. The Partnership recognizes the need for strategic advocacy and co-operation at the global level in order to communicate and trigger productive discussion not only on the complexity of the ―nutrient‖ but also the opportunities for cost effective policy and investment interventions by countries.

15

Nutrient Management Challenges in Africa: Nutrient Scarcity and Soil Degradation Endanger Food Security

Zhengxia Dou, University of Pennsylvania, School of Veterinary Medicine, Center for Animal Health and Productivity

382 West Street Road, Kennett Square, PA 19348 610 793-3074 douzheng@vet.upenn.edu

The green revolution of the 20th century tripled food productivity and helped lift hundreds of millions out of hunger in Asia and other parts of the world, but Africa missed out on the opportunity. There, per capita food production has actually declined considerably over the past 50 years. Now, the continent is in desperate need of an African green revolution to help feed its rapidly growing population, achieve food security, and combat poverty. Many factors contributed to the decades-long stagnant agricultural productivity in the region. Soil nutrient input far behind crop output has been a major constraint on productivity. Fertilizer use in Africa is the lowest of any developing region, averaging 9 kg/ha, compared to >100 kg/ha in Southeast Asia. Throughout much of the continent, unsustainable farming practices have severely depleted soil nutrients, resulting in a soil fertility crisis. Reversing this crisis requires nutrient management strategies that not only replenish the amounts of soil nutrients removed in harvested crops or lost through erosion or leaching, but also promote the gradual build up of soil fertility levels to support greater food production while minimizing potential environmental damage. Increased targeted use of both organic and inorganic fertilizers is critical. Also, Africa has more diverse farming systems than those in Asia and elsewhere, and greater numbers of livestock. Therefore, it is important to integrate animal nutrition and husbandry practices with nutrient management and crop production. An African green revolution can not materialize without scientific, technological and economic investment, the development and implementation of smart agricultural policies, and the concerted effort and support of local, regional, and international communities.

16

Keynote Panel

Nutrient Management Challenges and Progress in the Chesapeake Bay Watershed

17

Reducing Nutrient Pollution to Local Waters and the Chesapeake Bay:

Partnership, Progress and the Road Ahead

Jon M. Capacasa, U.S. Environmental Protection Agency, Region III, Water Protection Division Director,

1650 Arch Street, Philadelphia PA 19103 USA 215-814-5422 capacasa.jon@epa.gov

Historically, the Chesapeake Bay estuary is one of the most biologically productive regions in the world. The shallow waters that make this water body an ideal habitat for bay grasses, oysters, crabs and spawning fish also make it extremely sensitive to actions on the land. For several decades, more nutrients and sediment have flowed into the Bay due to growing populations with more wastewater, increased impervious surfaces, air emissions, and intensifying agricultural activities than the system can handle. As a result, the Chesapeake Bay suffers from harmful algal blooms, low oxygen, or ―hypoxic,‖ dead zones, and poor clarity that endanger living resources. The Chesapeake Bay‘s dead zones in 2011 may become the largest on record according to state officials.

The states within the Chesapeake Bay watershed, the District of Columbia, U.S. Environmental Protection Agency (EPA), and the Chesapeake Bay Commission have signed multiple agreements and joint directives to protect and restore the Chesapeake Bay. Since 1983, the Chesapeake Bay Program partnership has embraced voluntary, regulatory and management initiatives to analyze and reduce nutrient and sediment loads delivered to the Bay. Measurable progress has been documented from a baseline year of 1985. This progress has been in large part due to implementation of management practices on agricultural lands and wastewater treatment plant upgrades. However, excess pollution continues to impair water quality. As a result, EPA established the Chesapeake Bay Total Maximum Daily Load, or Bay TMDL, in December 2010 pursuant the federal Clean Water Act. This pollution diet, the largest established in the U.S. to date, sets limits on all sources of pollution that reach the Chesapeake Bay and is based largely on Watershed Implementation Plans crafted by the six watershed states and the District of Columbia. The Bay TMDL includes a rigorous accountability framework to demonstrate assurance that allocations will be achieved and maintained through a combination of federal, state and local actions, ongoing oversight and milestones to assess progress, and additional federal actions as necessary to ensure all practices necessary to achieve a clean Bay are in place by 2025. The Chesapeake Bay restoration effort, with its emphasis on partnership, engaging key stakeholders, accountability, inclusion of the best available information, support for innovation, and regular milestones to assess progress, provides an example for managing nutrients in other large ecosystems and watersheds.

18

Nutrient Management Challenges and Progress in the Chesapeake Bay Watershed

Douglas B. Beegle, Distinguished Professor of Agronomy, Department of Crop and Soil Sciences, Penn State University,

116 Ag Sciences and Industries Building University Park, PA 16802

dbb@psu.edu

Nutrient problems from agriculture in the Chesapeake Bay can be placed into two major categories. The first are systemic problems related to the structure of animal agriculture systems in the watershed. Much of the animal agriculture in the watershed is based on the significant importation of feed for the animals from off the farm, and often from outside the watershed. Since animals typically only convert a small proportion of the nutrients consumed into animal products, the remaining nutrients accumulate in the manure. Because of the economics of manure management, these manure nutrients are typically not returned to where the feed crops are produced, but rather are spread on land near the animal production facilities often in excess of crop requirements. Only modest efforts, such as subsidized manure transport and regional manure processing, have been focused on this problem. It is important to understand that these issues are beyond the control of the individual farmer trying to be profitable within this system. The other category of issues is on-farm nutrient management. Much progress has been made by research and Extension in the Bay watershed toward developing and implementing nutrient management systems. Universities, the USDA, and other public and private organizations have made major contributions to our understanding of the processes that can result in nutrient pollution and used that knowledge to develop management systems and technologies to help farmers achieve the maximum economic benefit from nutrients with minimum environmental impact. Much of the fundamental basis for nutrient management planning, which is the cornerstone of most nutrient management programs worldwide, has come out of work in the Bay watershed. Tools for planning such as improved soil and manure testing programs, the Phosphorus Index, and adaptive management concepts have been developed and put to use. Technologies such as minimum disturbance manure injection, a wide variety of best management practices designed to both improve agronomic efficiency and environmental protection, and improve animal feeding systems have been developed and introduced to the farmers in the watershed. The private sector has also been very active in developing new technologies for manure treatment, handling, and alternative uses. Most public programs and policies intended to address the nutrient pollution problems in the Bay have focused on on-farm nutrient management. Significant progress has been made in reducing nutrient pollution in the Bay, however, the progress has not met expectations. Most new initiatives designed to accelerate progress toward meeting environmental goals for the Bay continue to focus on encouraging or mandating improved on-farm management, usually without addressing the systemic nutrient balance issues in the watershed. This approach has created a strategic conflict between economic production and environmental protection. Most of the efforts to improve on-farm nutrient management are external to the marketplace and often in direct conflict with the producer‘s economic interests. It can be argued that, while improved management will continue to provide benefits, success will be limited unless the systemic problems that are beyond the farmer‘s control and are resulting in a regional nutrient imbalance, are also addressed.

19

Importance of Tidal and Non-Tidal Monitoring, Research, and Modeling in Past and Future Water Quality in the Chesapeake

Kevin G. Sellner, Executive Director, Chesapeake Research Consortium,

Edgewater, MD, USA 21037 The Chesapeake Bay and its tributaries are highly enriched from human activities on the land, resulting in excessive algal production, hypoxia/anoxia in bottom waters, and reduced habitats and living resources in its waters. The presentation will focus on the importance of data, interpretation, and modeling in the region‘s early identification of the bay‘s problems and importantly, the critical need for even more data, analysis, and modeling for a future ‗healthier‘ bay and its tributaries. The collection and interpretation of water quality data and the measurement and modeling of the processes that govern nutrient stocks in tidal and non-tidal waters were instrumental in identifying primary mechanisms for the bay‘s deterioration, i.e., heterotrophic demand and accompanying nutrient recycling, and therefore the factors that control these processes through land use. Subsequent measurements of nutrient recycling rates and oxygen demand have enabled development of highly resolved models that link nutrient loads to system responses. The models, in turn, have permitted scenario runs that alter loads and oxygen demand, thereby identifying land use practices needing improvement as well as possible alternative treatment technologies that might permit continuation of some practices that routinely yield high loads. Complicating future actions, however, is climate change and its impact on flows, severe events, and temperature increases; but continued examination of the impacts of these forcings on ecosystem processes by the scientific community should provide regional managers sufficient information for effective management alternatives for the changing system.

20

Delaware’s Role in Restoring the Chesapeake Bay

Jennifer A. Volk, Watershed Assessment Section, DE Department of Natural Resources and Environmental Control,

820 Silver Lake Boulevard, Suite 220, Dover, Delaware USA, Phone: 302‐739‐9939, Fax: 302‐739‐6140, Jennifer.Volk@state.de.us

The Total Maximum Daily Load (TMDL) established by the EPA identifies the necessary pollution reductions of nitrogen, phosphorus, and sediment for the six jurisdictions within the Chesapeake Bay Watershed. Along with Maryland, Pennsylvania, Virginia, West Virginia, New York, and the District of Columbia, Delaware‘s Phase I Watershed Implementation Plan (WIP), which contains details on how it will achieve desired load allocations, played a central role in shaping the final TMDL. To achieve the TMDL and restore water quality in local waters and the Chesapeake Bay, Delaware is implementing the pollution control strategies in its Phase I WIP while beginning development of its Phase II WIP. The Phase II WIP will build upon Delaware‘s endeavors to remediate water quality by engaging local governments, watershed organizations, conservation districts, citizens, and other key stakeholders to reduce water pollution. To stay on schedule and meet the load reductions called for by the EPA TMDL, Delaware‘s Department of Natural Resources and Environmental Control (DNREC) convened the Chesapeake Bay Interagency Workgroup made up of representatives from all DNREC divisions, the Department of Agriculture, Department of Transportation, Office of State Planning Coordination, County Conservation Districts, the U.S. Department of Agriculture, and other stakeholders. From this workgroup, nine subcommittees were formed to address the specific sections of the WIP; they are: Agriculture, Stormwater, Wastewater, Land Use and Comprehensive Plans, Restoration, Public Lands, Funding, Information Technology, and Communications. Subcommittees were charged with recommending and reviewing sub‐allocating methodologies to the various point and nonpoint sources within the watershed, assessing current data tracking and reporting systems, determining maximum implementation goals and methods to fill program and funding gaps, and assisting with writing and providing information for the WIP. These subcommittees are also communicating proposed actions to the respective stakeholder groups and soliciting their input on WIP elements. Key elements of Delaware‘s Phase I WIP will be presented, including strategies to reduce nitrogen, phosphorus and sediment loads from wastewater treatment plants; community on‐site wastewater treatment systems; septic systems; urban stormwater; animal and row crop agriculture; and degraded forests, streams, and wetlands buffers. Additionally, Delaware‘s plans to offset pollutant loads from future growth will be presented.

21

Adopting Innovations through Collaborative Agricultural Research to Improve Water Quality at Regional Scales

Peter Kleinman, USDA Agricultural Research Service, Pasture Systems and Watershed Management Research Unit,

3702 Curtin Road, University Park, PA 16802 peter.kleinman@ars.usda.gov

Andrew Sharpley, Dept. Crop, Soils and Environmental Sciences, 115 Plant Science Building

University of Arkansas Fayetteville, Arkansas 72701 sharply@uark.edu

Douglas Beegle, Dept. Crop and Soils, Ag Science and Industry Building, Penn State University,

University Park, PA 16802 dbb@psu.edu

Nutrient management innovation and advancement in the U.S. is strongly linked to collaborative research efforts. These efforts span state, regional, national and even international scales, and have been effective at advancing both the research itself and the tools that it produces. Using common protocols and providing flexibility to allow for adaptation to local conditions is key to the success of collaborative projects. It is perhaps because of the success and impact of past collaborative projects, most notably the Phosphorus Indexing Core Team (PICT) that eventually became the Organization to Minimize Phosphorus Losses from Agriculture (SERA-17), that regional collaborative research projects remain a mainstay of watershed efforts to balance agricultural production and water quality priorities.

In the Chesapeake Bay Watershed, manure management concerns have galvanized collaborative teams that are simultaneously addressing research, extension and technology transfer responses to watershed regulations. The Mid-Atlantic Water Quality Program‘s state-level nutrient accounting initiative quantified the extent of the nutrient imbalance caused by livestock distributions in the Bay Watershed. The ―Mule Barn‖ consultative group provided a mechanism for coordinating nutrient management guidelines across state lines, minimizing the conflicts seen in other regions.

Today, regional collaborative research has introduced new manure application technologies to address the water and air quality trade-offs associated with no-till. By quantifying multiple agronomic and environmental variables and by using whole-farm modeling, collaborative research teams have been able to convince federal and state agriculture programs to promote the adoption of minimal disturbance manure incorporation technologies. Reacting to emerging issues and strong political forces, regional teams are leveraging their collective resources to ensure that water quality recommendations remain science-based.

22

Adaptive Management Strategies: Improving Nutrient Management at Farm and Watershed Scales

Thomas Morris1, Haiying Tao1, Tracy Blackmer2, and Suzy Friedman3

Univ. of Connecticut1, Thomas.morris@uconn.edu; Haiying.tao@uconn.edu; Iowa Soybean Association2, tblackmer@iasoybeans.com;

Environmental Defense Fund3, sfriedman@edf.org

Society needs more efficient nitrogen (N) use in grain production. Water quality is declining from pollution by nitrate. Much of the nitrate in the water in areas with large acreages of grain production is the result of N applications for the grain production. One of the big questions for society is: how do we increase food production without polluting our water supplies? A growing number of farmers, scientists, agricultural service providers, and environmentalists think society can minimize pollution of water supplies and increase food production by using the concept of adaptive management, which was developed by ecologists.

Adaptive management concepts have been used to establish an extensive network of farmers, scientists, agricultural service providers, and environmentalists in the U.S. to improve N practices. The On-Farm Network has programs in 11 states working to improve N use efficiency and other practices used to produce our food. The procedure is straightforward: farmers objectively evaluate their N practices and use the results to adapt their practices for better efficiency. The methods of evaluation can include in-season and end-of-season testing of soils and corn plants for N availability, replicated strip trials, aerial images of corn fields, and discussion of the results by groups of farmers. The key to adoption of improved practices is the learning that occurs in the group meetings of farmers.

Farmers, like all adults, more readily adopt new information when they can discuss and explore new information in a problem solving context with data directly related to their problem. The information learned in the group meetings has led farmers to reduce N applications by 33 kg N ha-1 on average. Most fields received less nitrogen compared with the farmers‘ normal N rate; some fields received more N.

The process of adaptive management could easily be used to improve practices in all agricultural areas of the world. The concept is simple: farmers, and all who work to improve farming practices, learn best when involved in a participatory process with reliable data from farmers‘ fields that is directly related to a practice all agree needs improvement. The key component is meetings with farmers for discussion of the data. This fosters learning, which allows the integration of new information into current information to create an improved practice.

Data from thousands of fields collected in adaptive management programs shows a need to move away from traditional research trials with a narrow focus on whether the yield increase from N applications was statistically significant or not, to a broader focus on the probability that a given N practice will outperform another practice. Calculating the probability that one practice is more efficient than another will require large amounts of data, new ways of analyzing the data, and new relationships among farmers, scientists, agricultural service providers, and environmentalists. An adaptive approach to N management enables the development of these new processes and analyses to increase the efficiency of food production.

23

Nutrient Management Strategies for Dairy Based Agriculture

Quirine M. Ketterings1 and Karl Czymmek2

Nutrient Management Spear Program1, and PRODAIRY2, Morrison Hall, Department of Animal Science, Cornell University, Ithaca NY 14853

Qmk2@cornell.edu and kjc12@cornell.edu The future of dairy farming depends on producers‘ ability to manage nutrients for efficient production while minimizing environmental impact. Many factors have contributed to less than optimal nutrient use efficiencies on dairy farms, including a relatively low cost of fertilizer and low nutrient density of manure, poor understanding of the real value of manure (nutrients and organic matter), the lack of economical manure treatment and handling systems, and external price pressures/fluctuations. A variety of recent water and air quality concerns make it clear that farms will not be able to continue to externalize the environmental impacts of manure management in the name of economics. Solutions will vary by type of manure (species) and whether regional imbalances exist. In this presentation we discuss approaches to improving farm nutrient balances for dairies. To meet the challenges, a whole farm focus is needed. Improvements will need to include: (1) rations balanced for high production with minimal overfeeding of N and P; (2) optimizing manure and fertilizer application rate, timing, and method to conserve ammonia N and enhance recycling of nutrients (injection equipment, cover crops, double cropping, enhanced efficiency fertilizers and manure additives); (3) crop and bunker management to optimize preservation of nutrients; and (4) use of manure handling/treatment processes to reduce odor and loss of nutrients to the environment. To be successful in enhancing nutrient use efficiencies, we need to address farm nutrient imbalances and recognize multiple intervention points. This includes farmer-driven implementation of tools and technology, good record keeping, annual whole farm balance assessments, and use of crop and herd performance indicators. Examples from New York show that farm-implemented improvements in crop and ration P management have significantly reduced statewide and farm-level P balances. Similar improvements are underway in terms of N management where ration levels are lowered and more manure is spring-applied and incorporated for greater N conservation. Better sampling methods are being developed to assess timing of harvest, and farms are implementing manure handling and treatment options to help with odor control and nutrient management. Yet, there is a need for continued research and extension that leads to the development and implementation of affordable management alternatives. In addition, for greater impact, regulatory programs need to recognize and address nutrient imbalances by encouraging behavior that improves nutrient use efficiency. Land Grant Universities (LGUs) and research institutes should work with agencies and farmers to develop a practical, implementable, effective evaluation system that allows farms to be responsive and accountable, to be creative and flexible, and to strive to identify the win-win situations using outcome-focused benchmarks. And, last but not least, an integrated approach to addressing farm imbalances requires effective education and training of the next generation of farmers, farm advisors and regulators to address complex issues of an interdisciplinary nature.

24

Legacy Phosphorus: Management Options for the Chesapeake Bay Watershed

J. Thomas Sims,

College of Agriculture and Natural Resources, University of Delaware,

Newark, Delaware 19716-2103 302-831-2698 jtsims@udel.edu

Many agricultural soils in the Chesapeake Bay Watershed are now sufficiently saturated with phosphorus (P) to be significant non-point sources of P to surface and ground waters. The major contributing factor to soil P saturation has been decades of over-fertilization with P, particularly by organic residuals (animal manures, municipal biosolids) but also with commercial inorganic fertilizers. In the past 15 years state and national laws and regulations have evolved that now mandate adoption of best management practices (BMPs) to reduce P impacts on water quality. As implementation of regulatory measures has proceeded, difficult questions have arisen about how to address the contribution of “legacy” P – that phosphorus which has accumulated to very high values in soils from past applications. Strategies, policies, and technical innovations have arisen to provide at least partial solutions to managing organic P sources and the advent of nutrient management plans has markedly reduced the unnecessary application of commercial fertilizer P. However, even if applications of organic residuals and fertilizer P were to cease completely, environmentally significant nonpoint P losses from P-saturated soils can be expected from some agricultural cropland for years to come. Clearly, there is a need for a long-term strategy to address legacy P both to maximize its economic value as P fertilizer prices increase and to minimize watershed scale loading of P to surface waters. Given this, what new options can be conceived to manage legacy P in agricultural soils of the Chesapeake Bay watershed? This presentation provides an overview of the current status of legacy P in the Bay Watershed and suggests a range of approaches to improve environmental management of P-saturated soils.

25

Advances in Nutrient Management for Major Crops in China

Xinping Chen, Zhenling Cui, Minsheng Fan, Qing Chen, Rongfeng Jiang and Fusuo Zhang China Agricultural University, College of Resources and Environmental Sciences,

Beijing, 100193, China For feeding 20% of the world population with only 7% of the global arable land, China consumes almost one third of global nitrogen fertilizers. Chinese agriculture faces double challenges from both of food security and environmental safe. Managing root zone nitrogen supply is key to meeting crop demand while avoiding nitrogen losses to the environment. According to the nitrogen demand by high-yielding crops, we developed an in-season root-zone nitrogen management strategy, and demonstrated that it could significantly save nitrogen fertilizer input and maintain/even increase crop yields in major crops in China, such as wheat, maize, rice and vegetables. How to transfer this technique to countless smallholder farmers is a problem. Based on the understanding of biogeochemistry of nitrogen in the root zone, we simplified in-season root-zone nitrogen management to the strategy of ―controlling total amount and split in key seasons‖ for smallholder farmers in regional scale. Using this simplify N management strategy in ―national soil testing and fertilizer recommendation program‖, smallholder farmers could optimize their nitrogen fertilizer management without the need for expensive and time-consuming soil testing. Substantially improving crop productivity is a long-term challenge, especially in rapidly growing economies such as China. We developed a model-driven integrated soil–crop system management approach to develop a crop production system that achieved mean maize yields of 13.0 t ha−1 —nearly twice the yield of current farmers‘ practices—with no increase in N fertilizer use. Such integrated soil–crop system management systems represent a priority for agricultural research and implementation. As a result, since 2007, the increasing rate of nitrogen fertilizer consumption declined and crop production increased in China. It is the first time that the nitrogen use efficiency on the national scale increased over the past three decades.

26

Nitrogen and Phosphorus Flows in the Food Chain and Their Contributions to Non-Point Pollution in China

Wenqi Ma 1*, Ma Lin2,3, Hou Yong1, Gao Zhiling1, Zhang Fusuo2

Agricultural University of Hebei1, College of Resource and Environmental Science, Baoding, 071001, China;

China Agricultural University2, College of Resource and Environmental Science, Beijing, 100193, China;

Wageningen University3, P.O. Box 47, 6700 AA, Wageningen, the Netherlands. *Contributing author: mawq@hebau.edu.cn

Agricultural production, driven by the food requirement in China, has dramatically increased during the last decades, and has significantly depended on chemical fertilizer and feed additive application. At the same time, nutrient flows have increased, the traditional nutrient cycling mode in the food chain has been interrupted, and nitrogen (N) and phosphorus (P) losses to the environment have increased. Therefore it is urgent to address the long-term nutrient flows in the whole food chain for designing integrated nutrient management strategies at present and in the future. Here, we report on N and P flows in the food chain (crop production, animal production and food consumption sectors) and their contributions to non-point pollution in China during the period 1980-2009 using the model NUFER (NUtrient flows in Food chains, Environment and Resources use).

Our results showed that N and P flux has been increased from 1980 to 2009 by 0.7 and 0.6 times in food consumption, 1.7 and 2.5 times in crop production and 2.2 and 2.8 times in animal production. From 1980 to 2009, the chemical fertilizer consumption increased from 3.3 to 6.1 kg for N and 3.3 to 9.8 kg for P in order to produce 1 kg food N and P, and the losses of N and P from the whole food chain to the environment were increased from 4.2 to 8.6 kg for N and from 0.9 to 4.6 kg for P. It was discovered that these was a significant increase in the contribution of N and P losses to water bodies from animal production, accounting for 43% and 73% of total N and P losses from the food chain to water bodies in 2009, while the corresponding ratio was 6% and 12% in 1980, respectively. Additionally, taking the food chain as a whole, the contribution of N loss to water bodies has increased from 26% to 38% of the total N loss between 1980 and 2009.

It was concluded that human food consumption, especially increasing animal food plays an important role for N and P flows in the whole food chain and their losses to the environment during the past decades, therefore the new strategies of integrated nutrient management of the whole food chain need to be developed for the future.

Keywords: Nutrient management, Nutrient flow analyses, NUFER model, food security, Environment

27

Nutrient Management Policy in China: History, Current Status, Future Trends

W.F. Zhang*, Y.X. Li, L. Ma, F.S. Zhang 1College of Resources and Environment Sciences, China Agricultural University, Beijing

100193, China *Contributing author: wfzhang@cau.edu.cn.

China feeds 22% of the World population with 9% of World‘s arable land. China‘s success in agriculture is mainly attributed to the widespread application of various chemical inputs, especially fertilizers. In addition, raising the level of farmers‘ income largely depends on the fertilizer use. Currently, 35% of the World‘s chemical fertilizer is produced and consumed by China. In the past 10 years, the increase of the production and consumption of fertilizer in China contributed 60% of that in the World. Furthermore, China has become the most developed country in animal production, of which the organic materials produced, including organic wastes, sewage sludge and straws, have reached 4 billion tons each year, providing pure nutrients up to 60 million tons. The application of fertilizers contributes 30%-50% for China‘s grain yield, and greatly stimulates the development of vegetables, fruits, fibers, fisheries and forestry. However, the widespread use of fertilizers, particularly the increased reliance upon chemical fertilizers in the recent decades, has caused problems for sustainable development of Chinese agriculture. Overuse of fertilizers has generated many environmental problems, such as the energy shortage, resource depletion, water eutrophication, soil acidification, and greenhouse gas emissions. Results of numerous recent scientific research showed that there are solutions for China to further improve the food production without increasing fertilizer inputs. A change the policy scheme is the first step to ensure that small farmers adopt this kind of advanced technology. Therefore, the improvement of policy management has become the premise of the nutrient management system in China.

Since the 1960s, Chinese government implemented the incentive policy instruments for promoting the development of the fertilizer industry. Until the end of 1990s, China achieved self-sufficiency in nitrogen and phosphorus fertilizers. To further promote the development of fertilizer industries, Chinese government provided the subsidy on electricity use, natural gases, and coals for fertilizer industries, applied low-cost policy in transportation of fertilizers, and exempted the VAT from the fertilizer companies since the beginning of the 21st century. In 2005, the subsidies on domestic fertilizer industries reached 40 billion RMB, which accounted for 17% - 21% of the overall revenues of the whole fertilizer industry. Because of the excessive production of fertilizers, Chinese government began to gradually reduce the subsidies, liberalizing the fertilizer market. Consequently, fertilizer prices increased. Hence, Chinese government formulated the comprehensive agricultural subsidy policy, aiming to provide subsidy on fuels and fertilizers directly to farmers. In 2010, the subsidy reached 115 billion Yuan. Furthermore, in order to mitigate impacts of climate change on agricultural production, Chinese government provided up to 2.7 billion RMB subsidies on the application of foliar fertilizers in wheat and rice production in 2011. These subsidy policies aiming to reduce costs of agricultural production for farmers play a huge role for promoting the food production. However, these policies directly or indirectly caused the overuse of fertilizers in China; at the same time, they led to the development of the fake fertilizers. China has to accelerate the construction of the fertilizer market, improve the fertilizer quality, and change the farmer‘s behavior through market regulations.

28

In order to improve fertilizer use efficiency caused by the excessive use of fertilizers, Chinese government launched the soil testing and fertilizer recommendation project in 2005, which has covered 2498 agricultural counties and the cumulative investment reached 4.25 billion Yuan by the year of 2010. The project played an important role in improving the farmers‘ awareness of scientific application of fertilizers, and is important to rebuild the agro-technical extension in rural China. Driven by this project, although each county has established a soil testing laboratory, and the majority of farmers received the fertilizer recommendation cards, it will still take a longer time to achieve the ultimate scientific use of fertilizers for all farmers. Meanwhile, in order to promote the soil quality, Chinese government launched the subsidy programs for production and use of organic fertilizers. These subsidy programs are tax relief and low-pricing electricity use on producers of organic fertilizers, direct subsidies for farmers purchasing the organic fertilizers, and subsidy on returning straws to field. These subsidy programs are mainly to increase the organic nutrients in Chinese farmland, but the problem of how to quantify these nutrients is still not resolved.

In recent years, environmental problems have become more and more prominent. Chinese government has begun to pay close attention to environmental management policies, and through policy instruments to set up some nitrate vulnerable zones where the use of fertilizers is restricted. For instance, the municipal government of Beijing has forbidden fertilizer use around Miyun reservoir; the use of chemical fertilizers has been prohibited within 5 km in the coastal area of Dalian city; 20% of the fertilizers have been reduced in Taihu lake area in 2010, etc. Chinese government has also limited the use of electricity and natural gas for fertilizer production towards a low carbon economy in 2010. However, the environmental management systems are only established on a regional scale and no laws or regulations have been applied on a national level. Furthermore, there have been no specific regulations on nutrient management (i.e., lack of rules or laws to regulate nutrients which are from soil, deposition and organic materials). In addition, the way of nutrient management is only based on executive orders, no connections with the market, laws, and education forms.

EU nitrogen assessment proved that the environmental cost from reactive nitrogen is around 70-250 billion euro, although EU has taken numeric measures on this issue over the last two decades. Nowadays, the environmental cost in China could be higher than that in EU. It is a huge challenge for China to reduce environmental risk while maintain agriculture development through nutrient management technology and policy. To build up an integrated policy scheme is an emerging demand for China, which aims to establish and improve the fertilizer market, to build up the system of farmer training, to promote agro-technical popularization, and to improve policy making in the area of environmental management. Chinese government has to draw lessons and experiences from other developed countries.

29

Advances in Fertilizer Technologies for Improved Nutrient Management

Gregory D. Binford, PhD, Associate Professor/Extension Specialist, University of Delaware

152 Townsend Hall, Newark, DE 19716 302-831-2146 binfordg@udel.edu

In recent years, there has been an increased focus within the fertilizer industry to improve fertilizer-use efficiency through the use of ―Enhanced Efficiency Fertilizers,‖ which refers to any technology that will reduce the risk of nutrient loss and improve the potential for plant uptake. These technologies include ammonia volatilization inhibitors, nitrification inhibitors, and slow-release fertilizers.

Most of these technologies have been available in the fertilizer industry for decades, but the popularity of these technologies has increased greatly in the past few years. This increased interest has been stimulated by large increases in the cost of fertilizers and the prices paid for harvested grain. Also, the environmental pressures focusing on improving nutrient-use efficiency have increased greatly during the past decade.

With any new technology, the first important step is to demonstrate that the technology does in fact provide the intended outcome, whether that is ammonia or nitrification inhibition or a slow-release of available nutrients. After the technology has been proven, the next step is to determine the relative value to specific production situations. Because of the excitement of these technologies and the current positive economic situation in production agriculture, sometimes these new products are brought to the market place with a lack of this information.

This presentation will provide information on the current status of these new technologies and where they have their greatest value. These results will include field studies done in Delaware and other states, as well as basic studies done by other laboratories to evaluate the ability of the technologies to provide the intended benefit.

30

Nutrient Management at the Catchment Scale: European Union Policy Expectations in Ireland

Phil Jordan, Agricultural Catchments Programme, Teagasc, Wexford, Ireland

phil.jordan@teagasc.ie

In the European Union, the Water Framework Directive is the overarching legislation for managing water resources and pressures on these resources have both mitigation and monitoring Directives. The Nitrates Directive is the program of measures devised to mitigate agricultural nutrient losses from land to water and is ratified into member state legislation according to vulnerable zones or whole territory approaches.

In Ireland, a whole territory approach has been adopted, largely due to the risk of phosphorus loss from agricultural land, and the Nitrates Directive National Action Programme regulates the magnitude and timing of nutrient management and associated activities that determine nutrient mobilization. These policies are a negotiated end-point between the needs of intensive agricultural production and water resource protection and there have been several iterations since its designation in 2003 and the first Action Programme in 2006. Evaluations of these policies are undertaken at several scales and include national soil inventories, farm facilities surveys, water body chemical and biological monitoring and more focused biophysical and socio-economic monitoring of agricultural catchments.

The challenge for supporting sustainable intensive agriculture has never been greater as Ireland seeks to increase production in certain sectors and at the same time realize water resource management obligations. Grant aided farm facilities upgrades via the first Action Programme coupled with optimization of nutrient management provide a foundation for growth. In national terms, soil inventories indicate a decrease from high soil phosphorus indices but in some soils these latter high indices can be sustained due to lengthy declines following legacy management. At smaller catchment scales, the riskier catchments, in terms of nutrient loss, appear to be more aligned with soil susceptibility to runoff rather than due to excessive soil fertility alone and this is likely to exercise policy makers in future iterations of the Action Programme. Untangling the relative impacts of multiple point and diffuse nutrient sources on flowing and standing water bodies in catchments remains a challenge for policy evaluation and a review of monitoring metrics will no doubt be required.

With legacy issues, source and transport limitation issues and the complexity of interacting nutrient source transfers in agricultural catchments, it may become important to manage expectations of water resource policies, as well as the mode of mitigation.

31

Managing Crop Nutrients Locally for Global Results with 4R Nutrient Stewardship

Tom Bruulsema, PhD, CCA, Director, Northeastern Region, North American Program, International Plant Nutrition Institute,

18 Maplewood Drive, Guelph, Ontario, Canada N1G 1L8 519-821-5519 Tom.Bruulsema@ipni.net

The fertilizer industry has adopted 4R Nutrient Stewardship as a means of connecting the adoption of local farm practices to sustainability impacts at larger scales. The 4 "Rights"—source, rate, time and place—are defined by their contribution to social, economic and environmental improvement. The concept emphasizes producer-level decision-making on nutrient management practices to attain stakeholder-selected sustainability goals and indicators which can be applied to cropping systems.

The 4R concept has been applied successfully to the development of a protocol for greenhouse gas abatement through reductions in agricultural nitrous oxide emissions in Alberta, and to the issue of loadings of soluble phosphorus into Lake Erie. Geospatial information on nutrient balances and soil test levels across North America serve as partial indicators of progress toward more sustainable agriculture. The 4R concept is also being promoted in Argentina as a strategy for fertilization of maize for sustainable intensification of cropping systems. In this strategy, measurements of fertilizer impact on nitrate leaching, ammonia volatilization, and phosphorus runoff are made in addition to impacts on yields.

In India, application of 4R Nutrient Stewardship addresses the issue of nitrate accumulation in soil through site-specific nutrient management. The approach includes the use of geographic information systems to map nutrients on small scales and across whole states, for refinement of nutrient recommendations, and the use of optical sensors for site-specific nitrogen management. In China, the concept guides a strategy for improving nitrogen use efficiency in grain crops, by encouraging improved evaluation of soil fertility, better use of organic resources, and use of controlled-release fertilizers and fertigation.

The global applicability of the concept—the four local practice factors and the end goal of sustainability improvement—facilitates communication to audiences who may not be familiar with agriculture, but are nonetheless important stakeholders of the agri-food system.

32

Managing Animal Manure Nutrients for Optimum Yields and Water Quality

Rory Maguire, Associate Professor, CSES Dept. (0404), Virginia Tech, Blacksburg, VA 24061, USA

540-231-0472 RMAGUIRE@vt.edu

Animal manures have been used as a nutrient source in agricultural crop production for centuries. However, intensification of animal production in developed and many developing countries has been occurring over the last few decades. Economies of scale have led to intensive animal production being concentrated in relatively small geographic areas. This modern animal production relies heavily on the importation of animal feed and fertilizers, and a local imbalance in manure nutrients available relative to local crop nutrient requirements. For example, a study by Maguire et al. (2007) showed that in 10% of U.S. counties, there was an excess of manure phosphorus relative to local crop needs, due to intensive animal production. Concerns over the fate of nitrogen and phosphorus in these animal manures has led to concerns over water quality, and increased regulations covering land application of manure.

Improvements in manure management can be put broadly into two categories, 1) improving the management of land application of manure, and 2) alternative uses for manure. Advances improving the management of manure have generally come a long way, while alternative uses of manure are in an earlier stage of development. Improved methods of manure management include proper nutrient management that takes into consideration soil testing, crop needs and nutrient availability in manure. Other methods are designed to prevent nutrients from reaching water, such as the Phosphorus Index, buffers, controlled drainage and exporting manure from areas with excess manure nutrients. Alternative uses that are under serious consideration include manure to energy, by several methods including combustion, pyrolysis and anaerobic digestion.

In this presentation I will concentrate on more recent developments such as manure injection, which can decrease nutrient losses to the environment and capture more manure nitrogen for crop production. I will also look into some recent developments in alternative uses such as pyrolysis of manure to biochar, which is a beneficial soil amendment that can sequester carbon and increase beneficial soil properties.

Maguire, R.O., D.A., Crouse, and S.C. Hodges. 2007. Diet Modification to Reduce Phosphorus Surpluses: A Mass Balance Approach. Journal of Environmental Quality. 36:1235-1240.

33

Canada’s Nutrient Management Challenges: Advances in Agricultural Best Management Practices for

Food Security and Water Quality

Don Flaten, PhD, Chair of the National Centre for Livestock and the Environment and Professor, Department of Soil Science, 362 Ellis Building,

University of Manitoba, Canada R3T 2N2 204-474-6257 Don_Flaten@UManitoba.ca

Canada is fortunate to have an agricultural land base and reserves of energy and nutrients that are relatively large for its population of 34 million people. As a result, Canada's overall annual trade surpluses in food and fertilizer are in the range of $5-11 billion and $0.6 to 1.0 billion, respectively. However, due to concerns about economic and agronomic efficiency, as well as environmental issues such as water quality, this abundance of resources for food production does not allow Canadian farmers to be wasteful of land, fertilizer and manure nutrients.

Canadian farmers are generally careful with the source, rate, timing and placement of fertilizer and manure application, as part of their traditional "source management" beneficial management practices (BMPs). Synthetic fertilizers are usually applied in balance with crop requirements for and/or removal of N and P. Livestock manures are traditionally applied in balance with crop requirements for N. However, as a result of manure's low ratio of available N to total P, this practice has created a surplus of manure P application in excess of crop removal in some areas where livestock production is intensive. An increasing majority of fertilizers are applied in spring, immediately prior to planting or at planting with "one-pass" equipment for planting and fertilizing. However, given the challenges of Canada's short growing seasons and narrow planting window, plus compaction problems with manure applicators, most livestock manure is applied in the fall. Fortunately, most fertilizers and manures are banded, injected or incorporated under the soil surface to minimize losses and maximize plant availability of nutrients.

One of the reasons why source management BMPs are very important in Canada is because most of Canada's farmland is located in the Prairie region, where the landscapes are nearly level and the climate is semi-arid, with cold winters and warm summers. As a result, most nutrient losses from this region occur in the dissolved form, during spring snowmelt over frozen soils, when vegetation is dead or dormant and interception of mobilized nutrients is very difficult. Therefore, some "transport management" BMPs that work well for reducing P loss in rainfall runoff over sloping landscapes (e.g., conservation tillage and vegetative buffer strips) do not perform well in the Canadian Prairies.

Addressing these overall challenges requires a "systems" approach, with multi-disciplinary expertise and collaboration among farmers, researchers, Extension specialists, private industry, governments and non-government organizations. A couple of examples of this approach in Canada include the National Centre for Livestock and the Environment (NCLE), led by the University of Manitoba and the Watershed Evaluation of BMPs program (WEBs), led by Agriculture and Agri-Food Canada.

34

Advances in Sensing Technologies to Improve Nutrient Management

Wade Thomason, PhD, Associate Professor/Grains Specialist, Virginia Polytechnic Institute and State University, 422 Smyth Hall (0404), Blacksburg, VA 24061,

Tel: 540-231-2988, Fax: 540-231-3075, wthomaso@vt.edu

Remote sensing technologies have the potential to increase efficiency of farm inputs and to minimize the environmental impact of farming. Crop performance and response to nutrient inputs varies substantially in both time and space. Soil and crop sensing technologies offer the potential to assess and respond to this variation with management decisions and inputs in real time. Current recommendations for intensively managed soft red winter wheat (SRWW) in Virginia call for N to be applied at Zadoks growth stage (GS) 25 based on tiller density thresholds and at GS 30 based on tissue nitrogen (N) concentration. Determining wheat tissue N content requires physical sampling of multiple locations in each field as well as a time lag between sampling and return of laboratory analysis. A system that can determine N needs at GS 30 as accurately as tissue N content but that can generate values in real time is needed. The objectives of these studies were to evaluate the GreenSeeker as a tool to estimate GS 30 N needs of SRWW and to validate the performance of variable rate N applications to SRWW using the RT 200 system. Over 16 site years, grain yields were similar for wheat receiving N based on the Virginia wheat algorithm and the standard method of determining wheat N needs based on GS 30 tissue N concentration. The Virginia algorithm treatment required seven percent less N to reach these yields. Studies in corn have resulted in similar yields between the farmer prescribed rate and the Virginia Corn Algorithm rate, which was, on average, 20% lower than the farmer standard rate. In addition to these regional examples, this presentation will discuss the state of the science for crop and soil sensors, their performance and limitations, and the impacts of these technologies on the science and policy of nutrient management

35

Managing Agricultural Drainage Waters to Protect Water Quality

Joshua M. McGrath, Ph.D., Assistant Professor, Soil Fertility and Nutrient Management Specialist,

Department of Environmental Science and Technology, College of Agriculture and Natural Resources,

University of Maryland Agricultural drainage ditches represent a direct pathway for high nutrient loads such as phosphorus (P) to be transported from fields to surface waters. Most practices used to reduce P loading from agricultural fields target overland flow and sediment bound P; however, P transport in these landscapes can be dominated by subsurface transport of dissolved P. Filters have been designed and are currently being field-tested that utilize industrial by-products as P sorbing materials (PSMs) to remove P directly from ditch flow. Several PSMs have been evaluated in the laboratory to assess their ability to remove P from ditch flow. Models have been developed to predict P removal and filter longevity using these materials. Currently, filters are being evaluated in different settings, including stormwater retention ponds on golf courses and a poultry farm and in ditches draining agricultural fields, to validate the models and more fully develop filter designs. Filter structure design, P removal effectiveness of by-products, and overall impact on water quality will be discussed. Field prototypes of the proposed system have shown a high likelihood of success, removing approximately 60 – 90% of the P from treated water. In addition to removing P from ditch water these treatment systems have the potential to remove nitrogen, sediment, and other contaminants.

36

Improving Nutrient Management by Advancing Irrigation Management

James Adkins, Associate Scientist, Irrigation Engineering

University of Delaware, Carvel Research and Education Center Georgetown, DE 19947

302-528-5957 adkins@udel.edu

Irrigation provides farmers with a means to stabilize yields and increase profitability to prevent serious economic losses due to crop failure. Mismanaging irrigation and fertigation, however, can create economic and environmental problems. For optimum nutrient uptake and yield, soil water in the crop root zone must be maintained between desirable upper and lower limits of plant available water. Under-irrigation typically results in reduced crop yield and failure to use applied nutrients efficiently; whereas over-irrigation increases nutrient leaching, disease pressure, water loss, and energy costs. Research has shown that by increasing irrigation efficiency, crop yields and nitrogen use efficiency can be increased, nitrate leaching can be reduced, and the loss of residual nitrogen to ground waters between growing seasons can be minimized. Currently, there are many different strategies that growers can use for irrigation management. They include; advice from crop consultants, computer irrigation management programs that account for evapotranspiration (ET), the ―checkbook‖ method, tensiometers, the ―feel‖ method, experience and intuition. However, most rely solely on a checkbook method or experience and intuition to schedule irrigations and rarely monitor soil moisture. Quantitative soil moisture measurements are an integral part of any effective irrigation scheduling program. Soil moisture readings can be used by themselves to schedule irrigations, but they are most valuable when used in combination with other methods of scheduling such as a simple checkbook method or an ET based computer model. Soil moisture readings can determine initial soil moisture balances and update these balances throughout the irrigation season. Installation of moisture sensors at multiple depths gives the ability to determine when to irrigate and how much should be applied. With center pivot irrigation systems, field calibration of the timer setting chart is critical to ensure the desired application rate. Recent testing has shown ~50% of center pivots had incorrect timer setting charts and in most cases, the charts were predicting ~25-50% more water was being applied than actually occurred. Through the combined use of improved scheduling techniques, soil moisture sensing and irrigation system calibration crop nutrient use efficiency can be improved and nutrient leaching beyond the crop root zone can be minimized.

37

Abstracts of Posters Presented on Monday, August 22, 2011

38

Pesticide Application Might Be Optimized through Using Integrated Nitrogen Management

Zhang Chaochun1*, Guo Mingliang1, Tang Li2, Zhang Fusuo1

China Agricultural University1, Department of Plant Nutrition, Beijing, P.R. China. 100193; Yunnan Agricultural University2, Department of Plant Nutrition, Kunming, Yunnan, P.R. China.

650201 *Corresponding author: zhangcc@cau.edu.cn.

Yield loss from pest or disease damage is one of the factors limiting crop production, and farmers tend to overuse pesticides to reduce yield loss. Overusing pesticides can not only bring harmful pollutants to the environment but also increases risk to human health via the food chain.

By scoring the data from the yearbook issued by the statistics bureau we explored the pesticide application problems present in China; a two-year field experiment conducted in Yunnan province in China was designed to investigate the impact of nitrogen application on rice disease severity.

Pesticide production (100% active ingredient) in China in 2006 reached 1.30 million tons/year and was about 2500-fold of that in 1950; pesticide application, total pesticide application (pesticide commercial product) in China in 2008 was 1.67 million tons/year, increasing by 129% compared with that in 1990. Pesticides were mainly used on the major crops. Vegetable production was the largest consumer, 162 dollars/ha (cost of pesticide) on average, and cotton production was second, 105 dollars/ha. Rice production was 51.6 dollars/ha; other crops, including oilseed crops, wheat and maize, roughly cost 23.4 dollars/ha in pesticide application.

The two-year field experiments showed that rice blast severity was significantly decreased with nitrogen application being brought down from 450 kg N/ha to 150 kg N/ha and reached the least severity when nitrogen was applied according to an integrated nutrient management plan. Plotting pesticide consumption with nitrogen consumption, a positive correlation relationship was seen, indicating that nitrogen application should impact significantly on pesticide application on a large scale.

We propose that pesticide application in China could be optimized using integrated nutrient management.

39

Using Treated Municipal Wastewater for Agriculture: A Review of a Pilot Study and Regulations in Delaware

James L. Glancey, Ph.D., P.E., University of Delaware, Newark, DE jglancey@udel.edu

Marlene M. Baust, P.E., Department of Nature Resources and Environmental Control, Dover, DE

Marlene.Baust@state.de.us Brian Carbaugh, P.E., Artesian Water Company, Newark, DE BCarbaugh@artesianwater.com

Edwin Kee, Secretary, Delaware Department of Agriculture, Dover, DE Edwin.Kee@state.de.us Kenneth Branner, Mayor, Middletown, DE

kbranner@middletownde.org In 2009, new legislation was enacted in Delaware giving farmers the right to receive and recycle municipal wastewater for irrigating agricultural lands. A cooperative pilot project between the state, municipality, public utility, university and two farm businesses was conducted in 2010 on 130 hectares in which farmers applied treated and filtered municipal wastewater from the Town of Middletown on an as-needed basis. The results of this pilot project indicate that farmers can effectively grow crops with municipal wastewater and still comply with other regulations, BMP‘s, and laws including the Nutrient Management Act, which requires farmers to apply N and P only at crop removal rates. Additionally, the economic and environmental benefits to farmers receiving pressurized wastewater are significant. The elimination of pumping costs coupled with nutrients utilized in the wastewater results in savings of more than $20/ha as well as a carbon footprint reduction of more than 20,000 kg per 100 hectares irrigated.

Based on this study, the Delaware Department of Natural Resources and Environmental Control and the Delaware Department of Agriculture have drafted new regulations governing this practice. A comparison of these new regulations to practices and requirements in other parts of the U.S. and in other countries suggests that Delaware has developed guidelines that will maintain water and soil quality as well as protect public health.

40

Comparison of Methods for Estimating Poultry Manure Nutrient Generation within the Chesapeake Bay Watershed

Jim Glancey & Bill Brown, University of Delaware

Sec. Ed Kee, Mark Davis & Larry Towle, Delaware Department of Agriculture Jennifer Timmons, University of Maryland

Jen Nelson, USDA NRCS Maryland

As part of the Chesapeake Bay Program, the U.S. EPA has developed watershed models for estimating Nitrogen (N) and Phosphorous (P) loading into the Chesapeake Bay. These models include algorithms for estimating manure generation from poultry production within the Bay watershed using manure excretion and chemical composition coefficients from the 2004 ASAE Standard. These coefficients are based upon studies performed about 20 years ago, and as a result, do not reflect recent innovations in bird genetics, nutrition, and production practices. To understand the potential effects these and other technologies have had on poultry manure and nutrient characteristics, approximately 3000 manure samples taken from 1996 to 2009 were analyzed for trends in N and P concentrations. While there was no significant change in N concentrations over this period, there was a statistically significant decrease in P concentrations.

To determine the amount of manure generated from modern production practices, a survey of production estimates from various poultry producing states was made and revealed that rates of production range from 1.0 to 1.7 tons of manure per 1,000 birds produced. Using a value of 1.25 tons per 1,000 birds, a case study was performed for Sussex County, Delaware showing that about 260,000 tons of litter is produced annually in county; approximately 20% of the 1.46 million tons of fresh manure estimated from the 2004 ASAE standard. Using the manure N and P concentrations previously stated, actual N generation in the county was calculated to be about 15 million pounds which is 40% of the estimate using the 2004 standard. The actual P generation was calculated to be about five million pounds which is approximately half the current estimate using the 2004 standard.

41

Biochar-stabilized Sludge as an Organic Fertilizer

Yufang Shen1 and Mingxin Guo2,*

Northwest Agriculture & Forestry University1, The State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,

Yanglin, Shanxi, China Delaware State University2, Department of Agriculture & Natural Resources, Dover, DE 19901

*Corresponding author: (302) 857-6479; mguo@desu.edu Biochar is a promising soil quality enhancer and a carbon sink, but the material is nutrient-poor and needs to be applied in combination with chemical fertilizers for promoting crop growth; sludge from sewage treatment contains essential plant nutrients, yet the waste requires stabilization prior to being a usable biosolids fertilizer. Stabilizing sludge with organic waste-derived biochar is hypothesized to yield a nutrient-rich, carbon-stable organic fertilizer valuable for crop production and soil carbon sequestration. This study investigated the feasibility of stabilizing sludge with biochar and evaluated the fertilizer value of biochar-stabilized sludge. Biochar from pyrolysis of corn stalk at 400°C was added to dewatered sludge cake at 100-500 g kg-1 dry sludge mass. The mixtures were incubated at 30°C for 7 days to reduce odor and pathogens. The resulting biosolids were evaluated on odor, handleability, pathogen presence, nutrient availability, and heavy metal leachability. The products were further applied to an acidic sandy loam soil at 10 g kg-1 and leached intermittently with water for 130 days. Nutrient release kinetics of the amended soils were determined. It showed that biochar amendment at 25% of dry sludge solid mass resulted in granular, odor-minor, and nutrient-rich biosolids. The fertilizer value of the biosolids was 3.7-3.6-5.6. The N, P, and K supply capacity of the organic fertilizer was 13.8, 0.22, and 5.40 kg ton-1, respectively. Land application of biochar-stabilized sludge is recommended at 10 ton ha-1 to meet seasonal crop nutrient requirements.

42

Nitrogen Balances of Smallholder Farms in Major Cropping Systems in the Peri-urban Area of Beijing

Yong Hou1, Zhiling Gao 1, Lisa Heimann 2, Marco Roelcke 2,

Rolf Nieder2, Wenqi Ma1*

Agricultural University of Hebei 1, College of Resources and Environmental Science, Baoding, 071001, China;

Technische Universitaet 2, Institute of Geoecology, Braunschweig, 38106 Braunschweig, Germany,

*Corresponding author: mawq@hebau.edu.cn.

An in-depth understanding of nutrient management variability on the sub-regional scale is urgently required due to the dramatically rapid changes in cropping patterns and farmers‘ resource use in China. The soil surface nitrogen (N) balance and some of its influencing factors in three major cropping systems (cereal, orchard and open-field vegetable systems) were studied over a two-year period on smallholder farms in a representative peri-urban area (Shunyi District) of Beijing, where is characterized by very intensive agriculture and animal husbandry, with livestock densities reaching 15 livestock units ha-1.

Positive soil surface N balances resulted across all three cropping systems which were likely to induce a high potential risk of environmental pollution. The mean annual N surplus of the vegetable system (23 farms investigated) was 1574.6 kg N ha-1 yr-1, representing approximately three times the corresponding values in the cereal (531.2 kg N ha-1 yr-1, 21 farms investigated) and orchard systems (519.0 kg N ha-1 yr-

1, 24 farms investigated). Further analysis showed that animal manure was the major source of N input and the factor with strongest impact on the N surplus in the vegetable system, the input reached 1442.5 kg N ha-1 yr-1 on average or nearly 65% of the total N input. In the cereal system, however, over 70% of the total N input originated from chemical fertilizer which was the primary positive contributor to the N surplus, and in the orchard system the N surplus was strongly and positively correlated with both chemical fertilizer and animal manure. Furthermore, within each of the three cropping systems, N fertilization, crop yields and N balances showed large variances among different smallholder farms and the variability had a higher significance in the orchard and vegetable systems.

This study highlights that differences in farming practices within or among cropping systems should be taken into account when calculating nutrient balances and designing options to increase resource use efficiency and to alleviate environmental pollution on the regional or sub-regional scale.

43

Review of Nitrogen Fertilizer Production and Consumption in China

G.Q. Huang*, L. Wu, W. F. Zhang, F. S. Zhang

China Agricultural University, College of Resources and Environmental Sciences, 100193, *Corresponding author: hgq2012@gmail.com.

The Haber-Bosch synthetic ammonia process has supplied 48% nitrogen (N) for human society in the world (Erisman et al., 2008) but the tremendous environmental problems following excessive use of N in cropland introduced great concern in recent years (Sutton et al., 2011). N management, especially in China, is facing a challenge to supply enough food for the increasing population while maintaining good environmental quality. China already produces and consumes 35% N fertilizer, but has to feed an additional 120 million people in the next two decades. The development of N is a hot topic not only for China but also for the world. In 2010, China produced 48 Mt N as chemical fertilizer. According to farmer survey data, we found 32 Mt N used in traditional crop land, 2-3 Mt in aquatic systems, 2-3 Mt in forestry systems, 3-4 Mt in industry, and 4 Mt for export. China only has 9% of the world‘s arable land, but produced 19.4% grain, 51.7% vegetables, 19.5% fruit, 30.4% fiber, and 21.8% animal protein of the world‘s total. Although arable land per capita declined from 0.19 ha in 1961 to 0.09 ha in 2009, the grain supply increased from 285.2 kg/y/capita to 397.7 kg/y/capita, and animal protein consumption increased from 29.5 g/day to 73.1g/day. This means N fertilizer contributed to 59.6% N for Chinese human protein. In addition, per capita fruit and vegetable production received 86.8 kg/y and 395.6 kg/y in 2009, which is 1 and 2.7 times more than the global average. Furthermore, China‘s agricultural Gross Domestic Product increased from 69.2 billion dollars in 1961 to 5474.5 billion dollars in 2010. But the cost for N supply is very high. China consumed 56.8% high quality coal, 18.7% natural gas, and 2.3% electricity to produce 48 Mt N fertilizers in 2010. The environmental cost is also very high; for example, the greenhouse gas emission related to N was estimated to be 450 Mt CO2-eq. The contribution of N fertilizer to water pollution is more than 57%. There is an emerging demand to change the current situation, but we have to make joint efforts from the economy, social mechanisms, policy, and technology. China favors remaining self-sufficient for food supply production; therefore, China cultivated 55% land from barren, slope, salt, and desertification land. This kind of land requires more nutrient input but results in more nutrient losses. Even so, the limited land has farmers growing double crops or triple crops on the same land every year though it is difficult to get alternative nutrients from bio N fixation and organic fertilizer. The small-land farmers have limited education and training, which make technology and information not so accessible. The small pieces of land also make it difficult to use machinery to apply fertilizer in the right amount and the right place. To resolve China's N problem is a hot topic for the world. We have to find ways to improve soil quality, train farmers, find proper fertilizer products and use it with proper machinery, and encourage farmers to use organic fertilizers.

44

Review of China’s Grain Production in Last Seven Years

Y.X. Li 1, W.F. Zhang1*, F.S. Zhang1,

1College of Resources and Environment Sciences, China Agricultural University, Beijing 100193, China

Guarding food security is the foundation of promoting economic development and maintaining social stability for a country. China's grain productivity level has achieved tremendous improvement since the new China was founded. However, the grain productivity level hasn‘t been improving smoothly; setbacks occurred along the way. In 2003, grain yield dropped to 431 million tons, suffering a reduction of 15.8% from 512 million tons in 1998. Food security hidden behind this setback drew great attention of the Chinese government. Since 2004, the Chinese government has issued agricultural policies to encourage farmers to expand the planting of grains, and hence to promote the development of agricultural production. Those policies showed they were effective throughout the following seven years, as evidenced by the rapid growth of China's grain yields. By the end of 2010, the total grain output had reached 546 million tons, recording a 26.7% growth since 2003. Further study showed that major contribution of the grain yield growth came from three single crops: rice; the output growth of which accounted for 35% of that of the total grain yields; wheat, 25%; and maize, 53%. This study also showed that 92.5% of the national food production growth came from three areas: Northern China, Northeastern China, and the middle and lower reaches of the Yangtze River Area.

Generally, the two factors influencing grain output are sown area and grain yield per unit area. In-depth research on grain output growth in the above mentioned three areas showed that these two factors both recorded significant growth in the past seven years, while the grain sown area played a more important role than the other. Data showed that the grain sown area expanded 36.4% during the seven years following 2003 and grain yield per unit area increased 16.6% during the same period of time. Consequently, the sown area expansion contributed 57.3% to the total grain yield growth and the improvement of grain yield per unit area contributed 28%. In Northeastern China alone, the expansion of the sown area of rice and corn achieved significant results, recording 76.6% and 55.5% growth respectively. The agricultural policies released by the Chinese government since 2004 were of significant importance in encouraging farmers to expand the planting of grain, and ultimately promoted the development of agricultural production.

45

Integrated Assessment of Nutrient Management Options in the Food Chain in China: Effects on Nutrient use Efficiencies and Losses

L. Ma1,4*, F.H. Wang1, W.F. Zhang1, W.Q.Ma2, G.L. Velthof 3, W. Qin4, F.S. Zhang1, O. Oenema3,4

1 Department of Plant Nutrition, China Agricultural University, Key Laboratory of Plant-Soil Interactions, Ministry of Education, Beijing 100094, P. R. China ;

2 Agricultural University of Hebei, College of Resources and Environmental Sciences, Baoding, 071001, China;

3 Alterra, Wageningen University, Wageningen, P.O. Box 47, 6700 AA, the Netherlands; 4Wageningen University, Department. of Soil Quality, Wageningen, P.O. Box 47, 6700 AA,

The Netherlands *Corresponding author: ml332@126.com.

Nitrogen (N) and phosphorus (P) costs of food production have greatly increased in China during the last 30 years. Forecasts suggest that the food demand is rapidly increasing further due to population growth and shifts in consumption patterns during the coming decades, and that the N and P cost of the food produced will also increase further. However, these forecasts are not based on rigorous quantitative assessments, taking into account various possible options for a more sustainable nutrient management in the food chain at national and regional levels.

Here, we present the results of an integrated assessment of the N and P use efficiencies (NUE and PUE) and N and P losses in the food chain at regional and national scales, using the NUFER model. We present the results of five scenarios for the year 2030, using 2005 as baseline. We assumed that the animal numbers and crop yield will have increase by 70% and 40% in 2030, respectively, compared with 2005, considering the population increase and diet change. In the five scenarios (S1-5), we analyzed the effects of (1) business-as-usual (BAU), (2) balanced N and P fertilization in crop production (BNFc), (3) balanced N and P feeding in animal production (BNFa), (4) improved manure management (IMM), and (5) integrated nutrient management (BNFc + BNFa + IMM).

Our results show that in S1, mean fertilizer N and P consumption increased by 42% and 50%, respectively. Further, mean N and P losses increased by 85% and 70%, respectively. In S2, BNFc decreased fertilizer N and P consumption by 42% and 35%, and N and P losses by 31% and 27% relative to S1. In S3, BNFa decreased N and P use in animal production by 16% and 37%, N and P losses by 8% and 19%, relative to S1. In S4, IMM decreased fertilizer N and P consumption by 25% and 38%, and N and P losses by 32% and 43%, respectively, relative to S1. In S5, integrated options decreased the amount of ―new‖ N and P (chemical fertilizer and feed additive) input by 53% and 69%, and N and P losses by 59% and 67%, respectively, relative to S1. Our results indicate also that there are large differences between regions.

In conclusion, the business-as-usual scenario suggests dramatic increases in N and P losses for 2030. Implementation of a package of integrated nutrient management options would roughly nullify these increases in estimated losses and would greatly increase the N and P use efficiency in the whole food chain.

46

Life Cycle Environmental Assessment of Fertilization in Wheat, Maize and Rice Production Systems in China

Zhou Ran, Li Zhenyu, Hou Yong, Gao Zhiling, Ma Wenqi* Agricultural University of Hebei, College of Resources and Environmental Science, Baoding,

071001, China. *Corresponding author: mawq@hebau.edu.cn

This study aimed at assessing the environmental impacts of fertilization in wheat, maize and rice production systems in China on the basis of producing one ton of crop grain by using the life cycle assessment (LCA) method. The entire life cycle of crop production was classified into three sectors including exploitation of raw material, fertilizer production and plant cultivation, and environmental impacts of depletion of non-renewable resources, land use, global warming, soil toxicity, acidification and eutrophication were considered. An integrative indicator for environmental impacts, which had the capability to indicate the overall environmental burden derived from the products investigated, was calculated through the processes of normalizing and weighing all environmental impacts.

Results showed that the integrative indicator of fertilization for the maize production was the highest (0.402), followed by the corresponding values of the wheat production (0.384) and rice production (0.307). While on the basis of producing one ton of wheat, maize and rice grain, the environmental impact by the plant cultivation sector contributed 96.8%, 97.6% and 97.4% of the life cycle environmental impact, respectively. Of the six categories of environmental impacts considered, the contribution of wheat, maize and rice production systems to the eutrophication accounted for 83.6%, 87.2% and 79.1% of the life cycle environmental impacts respectively, which were mainly attributed to the ammonia volatilization and nitrate leaching. Moreover, the impacts of the fertilization in the three crop production systems on land use and acidification were also non-negligible. It was concluded through this study that optimizing chemical fertilizer utilization and increasing fertilizer use efficiency in crop production systems were the key points to reduce negative environmental impacts of the life cycle of wheat, maize and rice production in China.

47

Intra- and Inter-Annual Trends in Phosphorus Loads and Comparison with Nitrogen Loads to Rehoboth Bay, Delaware (USA)

Jennifer A. Volk1*, Joseph R. Scudlark1, Karen B. Savidge1, A. Scott Andres2,

Robert J. Stenger3, William J. Ullman1 University of Delaware1, School of Marine Science and Policy, Lewes, DE 19958;

University of Delaware2, Delaware Geological Survey, Newark, DE 19716; City of Rehoboth Beach3, 229 Rehoboth Avenue, Rehoboth Beach, DE 19971;

*Present address: Watershed Assessment Section, Delaware Department of Natural Resources and Environmental Control, 820 Silver Lake Boulevard, Suite 220, Dover, DE 19904

Jennifer.Volk@state.de.us (J.A.V.), scudlark@udel.edu (J.R.S.), asandres@udel.edu (A.S.A.), RJStenger@aol.com (R.J.S.), ullman@udel.edu (W.J.U.)

Monthly phosphorus loads from uplands, atmospheric deposition, and wastewater to Rehoboth Bay (Delaware) were determined from October 1998 to April 2002 to evaluate the relative importance of these three sources of P to the Bay. Loads from a representative subwatershed were determined and used in an aerial extrapolation to estimate the upland load from the entire watershed. Soluble reactive phosphorus (SRP) and dissolved organic P (DOP) are the predominant forms of P in baseflow and P loads from the watershed are highest during the summer months. Particulate phosphorus (PP) becomes more significant in stormflow and during periods with more frequent or larger storms. Atmospheric deposition of P is only a minor source of P to Rehoboth Bay. During the period of 1998 to 2002, wastewater was the dominant external source of P to Rehoboth Bay, often exceeding all other P sources combined. Since 2002, however, due to technical improvements to the single wastewater plant discharging directly into Rehoboth Bay, the wastewater contribution of P to the bay has been significantly reduced and upland waters are now the principal source of P on an annualized basis. Based on comparison of N and P loads, primary productivity and biomass carrying capacity in Rehoboth Bay should be limited by P availability. However, due to the contrasting spatial and temporal patterns of N and P loading and perhaps internal cycling within the ecosystem, spatial and temporal variation in N and P-limitation within Rehoboth Bay is likely.

48

Abstracts of Posters Presented on Tuesday, August 23, 2011

49

Spatio-temporal Variation of N concentration Reveals Control Mechanisms for Reducing N Export from a Human-impacted

Watershed

Luc Claessens, PhD, Assistant Professor, Department of Geography, University of Delaware, Pearson Hall Room 220, Newark, DE 19716

302-831-0871, luc@udel.edu

Human activities can lead to increased watershed N export, with associated detrimental effects on downstream aquatic ecosystems. I examined the spatial and temporal variation in N concentration across a 890 km2 human-impacted Mid-Atlantic watershed and addressed the following questions: (1) How does the spatial organization of land-use control watershed N export? (2) How important is in-stream N removal and what is the role of forested buffers? The study covered a range of flow conditions, including drought and wet conditions. I used a dense network of ~50 synoptic stations that were sampled bi-monthly for 3-4 years, supplemented with seasonal snapshot samplings. The results illustrate large temporal and spatial variability in N concentration. To examine spatial land-use effects, I applied GIS-based spatially-weighted approaches. The results show that spatially-weighted approaches (vs. the standard fractional cover/lumped approach) improve the predictive ability of land-use effects on N export. To examine in-stream N removal, I compared N concentrations across a wide range of discharges. Concentration-discharge analyses showed point sources (e.g., waste water treatment plants), and operational improvements could be detected. Concentration-discharge analyses also showed evidence of in-stream N removal, particularly during low-flow periods. Together with information on the spatial organization of land-use, it highlights the role of riparian forests and C-N linkages. This study demonstrates that spatial-temporal patterns of N concentration reveal existing and potential control mechanisms for reducing watershed N export.

50

Concentrations of Nutrients and Dissolved Organic Carbon (DOC) Across Different Landscape Positions in an Agricultural Watershed

Receiving Poultry Manure

Sudarshan Dutta1*, Shreeram Inamdar2, and Gurbir Singh1 1152 Townsend Hall, Department of Plant and Soil Sciences, University of Delaware, Newark, DE; 2 264 Townsend Hall, Department of Bioresources Engineering, University of Delaware,

Newark, DE. *Corresponding author: sdutta@udel.edu.

Excess application of animal manure on agricultural landscapes can result in the movement of nutrients, such as ammonium (NH4-N) and nitrate (NO3-N), and dissolved organic carbon (DOC) with agricultural runoff, which ultimately enter the aquatic environment. Excess nutrients in aquatic environments are responsible for environmental issues like eutrophication and algal abundance; whereas, DOC is considered a responsible constituent for transporting of organic and inorganic contaminants with runoff water. However, we know very little about how the concentrations of these chemicals vary spatially across the various locations in agricultural watersheds. We investigated the transport of ammonium (NH4-N) and nitrate (NO3-N) nitrogen, and DOC in an agricultural watershed located in the coastal plain soils of Delaware, which was subject to land-application of raw poultry manure. Specific questions that were addressed were: What are the surface runoff concentrations of NH4-N, NO3-N, and DOC in an agricultural field? How do the concentrations of these chemicals vary with the landscape positions in an agricultural watershed? How do their concentrations vary with time since application of manure in a summer growing season?

Poultry manure was applied to the agricultural field (corn field) at a rate of 9 Mg/ha in early spring (April, 2010). Sampling was performed for surface runoff water for six storm events extending 93 days (April-July, 2010) after manure application. Runoff was sampled at the edge of the field, and at upland and lowland riparian locations, and from the stream receiving the runoff. The NH4-N concentrations were in the range from 1 to 20 mg/L. The highest concentration was observed at the field edge; and concentration decreased significantly (p ≤ 0.05) from field edge to upland and lowland riparian locations, and in stream samples. The NH4-N concentration did not vary significantly (p ≥ 0.05) between the samples collected at the riparian zones and from the stream. At the field edge, the concentrations decreased with time since manure application at the field for initial few events and then reached equilibrium. The NO3-N concentrations were in the range from 1 to 8 mg/L and concentrations did not vary significantly (p ≥ 0.05) across the different landscape positions and with time for the collected samples. Interestingly, the DOC concentrations increased significantly (p ≤ 0.05) from field edge to upland and lowland riparian locations, and then decreased significantly (p ≤ 0.05) in the stream samples; however, the concentrations did not vary with time in each location. Overall, our results suggest that typical agronomic application of poultry litter in Delaware (once every three years) may not pose a significant threat in terms of nutrient and DOC transport with agricultural surface runoff.

51

Biotic and Abiotic Pathways of Phosphorus Cycling: Insights from Oxygen Isotopes in Phosphate

Deb P. Jaisi, University of Delaware, Department of Plant and Soil Sciences, Newark, DE 19716 jaisi@udel.edu

Ravi K. Kukkadapu, Pacific Northwest National Laboratory, Richland, WA 99352

ravi.kukkadapu@pnnl.gov Lisa M. Stout, Yale University, Department of Geology and Geophysics,

New Haven, CT 06520 lisa.stout@yale.edu

Tamas Varga, Pacific Northwest National Laboratory, Richland, WA 99352

tamas.varga@pnnl.gov Ruth E. Blake, Yale University, Department of Geology and Geophysics

New Haven, CT 06520 ruth.blake@yale.edu

A key question to address in the development of oxygen isotope ratios in phosphate (18Op) as a tracer of biogeochemical cycling of phosphorus is the nature of isotopic signatures associated with uptake and cycling of mineral-bound phosphate by microorganisms. Here, we present experimental results aimed at understanding the biotic and abiotic pathway of P cycling during biological uptake of phosphate sorbed to ferrihydrite and the selective uptake of sedimentary phosphate phases by Escherichia coli and Marinobacter aquaeolei. Results indicate that a significant fraction of ferrihydrite-bound phosphate is biologically available. The fraction of phosphate taken up by E. coli attained an equilibrium isotopic composition in a short time (<50 h) due to efficient O-isotope exchange (between O in PO4 and O in water; that is, actual breaking and reforming of P-O bonds) (biotic pathway). The difference in isotopic composition between newly equilibrated aqueous and residual sorbed phosphate groups promoted the ion exchange (analogous to isotopic mixing) of intact phosphate ions (abiotic pathway) so that this difference gradually became negligible. In sediment containing different P phases, E. coli extracted loosely sorbed phosphate first, whereas M. aquaeolei preferred Fe-oxide-bound phosphate. The presence of bacteria always imprinted a biotic isotopic signature on the P phase that was taken up and cycled. For example, the 18Op value of loosely sorbed phosphate shifted gradually toward equilibrium isotopic composition. However, the 18Op value of Fe-oxide-bound phosphate showed only slight changes initially but, when new Fe-oxides were formed, co-precipitated/occluded phosphate retained 18Op values of the aqueous phosphate at that time. Concentrations and isotopic compositions of authigenic and detrital phosphates did not change, suggesting that these phosphate phases were not utilized by bacteria. These findings support burgeoning applications of 18Op as a tracer of phosphorus cycling in sediments, soils, and aquatic environments.

52

Phosphorus Fractionation of Cattle Manure, Swine Manure and Poultry Manure in China

G. Li, H. Li, F. Zhang1*,

China Agricultural University1, Department of Plant Nutrition, Key Laboratory of Plant-Soil Interactions, Ministry of Education, Beijing 100193, P. R. China;

*Corresponding author: zhangfs@cau.edu.cn

In recent years, animal production in China showed a rapid growth from 20 million in 1980 to 1.4 billion ton in 2009. However, little research focused on the shift of manure phosphorus (P) fraction in China. This study was to determine the fractions of P in cattle manure, poultry manure, and swine manure collected from different provinces of China. All manures were analyzed using a modification of the sequential extraction procedure of Hedley et al. (1982) as described by Dou et al. (2000). We characterized P in manure for the relative dissolution and fraction distribution using deionized water (H2O), 0.5 M NaHCO3 (pH=8.5), 0.1 M NaOH, 1.0 M HCl, and sulfuric acid. The total P was 4.4-6.9 g P kg-1 in cattle manure, 10.7-31.4 g P kg-1 in swine manure and 11.2-16.9 g P kg-1 in poultry manure, dependent on collection locations. Water-extracted P was 1.4-3.7 g P kg-1 (25-56% of total P) in cattle manure, 7.0-11.6 g P kg-1 (22-65% of total P) in swine manure, and 3.0-10.0 g P kg-1 (30-60% of total P) in poultry manure. NaHCO3 extracted 20-36% of total P in all animal manures. The residual P was 0.1-0.2 g P kg-1 in manures. The labile P fraction (sum of H2O- and NaHCO3-extractable P) was 66 to 86% of dairy manure P, 60 to 80% of poultry manure P, and 50 to 90% of swine manure P. A large proportion of labile P in manure being extractable by H2O or NaHCO3 suggests that there was a great potential risk of P loss from manured fields. Analysis of animal manure samples collected from different provinces of China indicated that the amount and proportion of manure P was similar to Occident. Thus, further investigation relating to manure P fractions made for the best management of manure P and resulted in pivotal reduction of P losses.

Keywords: manure phosphorus; phosphorus fraction.

53

Interactive Impacts of Earthworm (Eisenia fetida) and AM Fungus (Glomus intraradices) on Change of Soil Nutrient Contents in

Hyphosphere and Rhizosphere

Huan Li, Xiaolin Li, Chong Wang* College of Resource and Environmental Science, China Agricultural University,

Beijing 100193, China

Two experiments were conducted to investigate the interactive impacts of Earthworm (E. fetida) and AM Fungus (G. intraradices) on change of soil nutrient contents in hyphosphere and rhizosphere. In Exp. 1, the interactive impacts of E. fetida and G. intraradices on change of soil nutrient contents in rhizosphere were studied under near natural conditions with pots buried in the soil of a maize field. Wheat straw was added as feed for earthworms. Root colonization, mycorrhiza structure, plant biomass and N and P contents of shoots and roots, soil available P, NO3

- -N and NH4+-N concentrations were measured at

harvest. Results indicated that mycorrhizal colonization increased markedly in maize inoculated with AMF, which was further enhanced by the addition of E. fetida. AMF and earthworms interactively increased maize shoot and root biomass as well as N and P uptake. However, there were no significant interactive impact of E. fetida and G. intraradices on soil available P, soil organic matter, NO3

- -N and NH4

+-N concentrations in the rhizosphere compared to control treatment. In Exp. 2, a two-compartment incorporating air-gap device was used to evaluate the interactive influence of E. fetida and G. intraradices on change of soil nutrient contents in hyphosphere. Wheat straw was also added in the hypha compartment as feed for earthworms Treatments included hypha compartment treated or not treated with earthworms. Soil NO3

- -N and NH4+-N concentrations, soil available P, Ph, soil organic matter were

measured after 8 weeks. Results indicated that AMF and earthworms interactively increased soil NO3- -N

and NH4+-N concentrations, soil organic matter in the hyphosphere. Therefore, it could be concluded that

earthworms and AMF interactively enhanced soil nutrient contents in hyphosphere, leading to greater nutrient uptake and plant growth.

Key Word: mycorrhizal colonization, two-compartment incorporating air-gap device, maize, plant N and P content

54

Optimization for the Removal of Salmonella, E. coli 0157:H7 and

E. coli O157:H12 from Water using Zero-Valent Iron

Krystal Shortlidge1, Casey Johnson1, Criztal Hernandez1, Dallas Hoover1, Chunjian Shi2, Pei Chiu2 and Kalmia E. Kniel1

University of Delaware1, Department of Animal and Food Sciences, Newark, DE 19716

University of Delaware2, Department of Civil and Environmental Engineering, Newark, DE 19716

Introduction: Escherichia coli O157 and Salmonella are a few of the microorganisms detected in ground water and surface water which are used for irrigation thus posing a threat to our food safety. Pathogenic E.coli has been the cause of many food borne outbreaks associated with fresh produce with implications of ―trace-back‖ to potential contamination of irrigation water. The use of zero-valent iron (ZVI) has been shown in studies to inactivate and remove chemicals and coliphages and may be potentially effective at removing E. coli as well. Methods: Three bacterial strains (E. coli O157:H7 4407, Salmonella Newport, E. coli O157:H12) were inoculated grown overnight and removal tested in columns or in batch tests containing sand and ZVI. The experimental 1:1 ZVI-sand column consisted of a 4 cm core layer of iron and two 2 cm sand layers at the top and bottom of the column. Inoculated artificial ground water (AGW) was continuously applied to the columns at a flow rate of ~1mL/min and the outflow was collected as 120x5mL samples. Batch tests to better understand the interaction of bacteria with the ZVI were performed in 15mL centrifuge tubes containing sand, ZVI, or the 1:1 mix. Column fractions and batch supernatant and pellet fractions were analyzed on selective media. Recovered E. coli cells were analyzed on tryptic soy agar with addition of nalidixic acid (50µg/mL) while recovered cells of S. Newport were analyzed on XLT-4 agar. Data was collected and analyzed by calculating the total removal for each of the columns. Results: Bacterial cells were removed by the ZVI column consistently at 2 logs greater than that by the sand-alone column. Removal efficiency varied with water type and bacterial strain. Batch tests and disassembly of the column support the idea that bacteria are inactivated by ZVI. ZVI and the sand and ZVI mix both bound bacteria in the batch tests and had significant removal compared to sand. A significant difference was seen in the binding of all three bacteria as a factor of time comparing ≤1 hr to 4 hr. Implications of Research: The indication of the results is that ZVI can remove bacterial pathogens including E. coli O157:H7 and Salmonella Newport from water. ZVI is a fairly inexpensive and simple additive to a sand filtration system.

55

Improvement of Fertilizer Nitrogen use in Corn Fields from Implementation of an Adaptive Management Program

Haiying Tao1, Thomas F. Morris1, Suzy Friedman2,

University of Connecticut1, Environmental Defense Fund2.

Nitrogen management for corn is challenging because N cycling in agricultural soils is a complex biological process, and the process is further complicated by uncertainty of weather and uncertainty in the amount of N availability from manures. Adaptive nutrient management strategies use field-by-field histories of N management practices and results from objective evaluations of the practices to continually improve the practices. Objective evaluations include replicated strip trials to compare one practice to another, N assessment technologies such as the presidedress soil nitrate test (PSNT), the corn stalk nitrate test (CSNT), and aerial images of corn fields. 105 farmers in the Chesapeake Bay area have participated in an adaptive nutrient management program for two to six years to improve N use efficiency. We will report the results of case studies of how farmers changed their N management based on information and learning obtained from the adaptive management program. For example, one farmer reduced his average rate of nitrogen application on 23 fields from 77 kg per ha to 44 kg per ha over four years, which resulted in a savings of $11,000 in N fertilizer costs.

56

Different Phosphorus Dissolution Behaviors of Poultry Litter (PL) and PL Char

Yue Wang1, University of Delaware, Department of Civil and Environmental Engineering, 166

DuPont Hall, Newark, DE, 19716, United States, 302-831-0890, ccmoon@udel.edu;

Paul T. Imhoff1, University of Delaware, Department of Civil and Environmental Engineering, 344A DuPont Hall, Newark, DE, 19716, United States,

302-831-0541, imhoff@udel.edu; Mingxin Guo2, Delaware State University, Department of Agriculture and Natural Resources,

1200 N. DuPont Hwy, Dover, DE, 19901, United States, 302-857-6479, mguo@desu.edu;

Pei C. Chiu1*, University of Delaware, Department of Civil and Environmental Engineering, 244B DuPont Hall, Newark, DE, 19716, United States,

302-831-3104, pei@udel.edu

University of Delaware1, Department of Civil and Environmental Engineering, Newark, DE, 19716, United States;

Delaware State University2, Department of Agriculture and Natural Resources, Dover, DE, 19901, United States

Leaching of phosphorus from manure to surface waters contributes significantly to eutrophication. We hypothesized that converting manure into biochar through pyrolysis could reduce the phosphorus leaching potential and thus represent a potential solution to this problem. The object of this research is to test this hypothesis by comparing the phosphorus dissolution behaviors of dried poultry litter (PL) pellets and PL char. One, two or five grams of PL pellets or PL char was mixed with 200-mL deionized water and shaken at 280 rpm for different durations. The solutions were then filtered and analyzed for orthophosphate, acid-hydrolyzable phosphorus by colorimetric method and total phosphorus by colorimetric method and ICP-OES. In addition, a number of physical and chemical analyses were conducted for both materials. The phosphorus in the water extracts of both PL and PL char was almost all orthophosphate. PL rapidly released large amounts of phosphorus and the release continued for weeks. Take 2g:200mL-sample for example, about 28% of the phosphorus was released to water within the first hour and 50% in the first day. In contrast, PL char released phosphorus slowly, giving phosphate concentrations 1-2 orders of magnitude lower than that from PL depending on the pH, despite its higher total phosphorus content than PL. Only 0.3% of phosphorus was released to water in the first hour. The phosphorus dissolution rate was approximately constant with time. After 12 days, the amount of phosphorus released from PL was more than 10 times greater than that from PL char. These results support that PL char may potentially serve as a slow-releasing and more sustainable source of phosphorus than PL for soil. Further investigation is necessary to elucidate the underlying mechanism that controls the phosphorus dissolution behavior of PL char.

57

Effect of Long-term Fertilization on Phosphorus Accumulation and Running off in Paddy Field of Purple Soil

(Typic Purpli-Udic Cambosols)

Mingxia Wen1,2, Xueping Li1, Xiaojun Shi1,3*

Southwest University1, College of Resources and Environment, Chongqing 400716, China;

Zhejiang Citrus Research Institute2, Taizhou, 318020, China; National Monitoring Station of Soil Fertility and Fertilizer Efficiency on Purple Soils3,

Chongqing 400716, China *Corresponding author: shixj@swu.edu.cn

The objectives of this study was to determine the effect of long-term fertilization on phosphorus (P) accumulation and run off in purple soil (Typic Purpli-Udic Cambosols) and provide a basic foundation for P fertilizer optimization in paddy field. A research was carried out by a 15 years‘ long-term fix experiment in Chongqing, China. The results showed that long-term P application resulted in P surplus in rice field of purple soil (Typic Purpli-Udic Cambosols) and moving downward from plough soil. The moving ability of P in soil profile was influenced by the amount of P fertilizer, type of organic manure and planting methods. The amount of P moving downwards increased with the increase of P fertilization rate. P of chemical P application combined with swine excrement treatment moved easily in soil than that of combined with straw on the condition of equivalent nutrient. Olsen-P content was 1.25~6.5mg·kg-1

higher in rice-rape rotation than in rice-wheat rotation and P moving capability was stronger in rice-rape rotation than in rice-wheat rotation. P moving downwards water bodies mainly happened in the first 10 days after paddy flooded water to transplant rice. P concentration of surface water was higher in the first 10 days after paddy transplanted than other times and later dropping sharply, after fertilization about 35 days, it was low and tended towards stability. TP concentration of surface water in every treatment differed greatly in 30 days after paddy transplanted, TP concentration of 1.5NPK+M treatment was highest, second was treatment of combining with swine excrement and the lowest was no P application treatment. TP concentration in rice-rape rotation was higher than rice-wheat rotation. Combining with swine excrement treatment increased the amount of soil P transporting and running off. Long-term application of P fertilizer, combined with swine excrement and rice-rape rotation all increased P surplus and the risk of P running off, so effective measures should be taken to prevent P running off in paddy-upland rotation system. In addition, it was forbidden to drain in the first 30 days after rice transplanted.

58

Poultry Litter Biochar for Enhancing Soil Fertility: Effects on Soil Water Retention

Susan Yi, University of Delaware, Department of Civil and Environmental Engineering, 166

DuPont Hall, Newark, DE, 19716, susanyi@udel.edu

Brandon Witt, University of Delaware, Department of Civil and Environmental Engineering, 166 DuPont Hall, Newark, DE, 19716,

bwitt@udel.edu Paul Imhoff, University of Delaware, Department of Civil and Environmental Engineering, 344A

DuPont Hall, Newark, DE, 19716, imhoff@udel.edu

Pei Chiu, University of Delaware, Department of Civil and Environmental Engineering, 344B DuPont Hall, Newark, DE, 19716,

pei@udel.edu

The pyrolysis of biomass produces renewable energy in the form of heat and biofuels, and, as a byproduct, biochar. Recent studies indicate that some biochars have a significant beneficial effect on the nitrogen cycle: biochar (1) has the ability to retain nitrogen within soils by enhancing ammonia and ammonium retention, (2) can reduce nitrous oxide emissions to the atmosphere and nitrate leaching from soil, and (3) enhance biological nitrogen fixation and plant utilization of nitrogen. While these benefits have been observed in some laboratory and field experiments, a mechanistic understanding of biochar‘s impact on the nitrogen cycle is lacking.

We study the impact of biochar produced from poultry litter (PL) on the nitrogen cycle, beginning with an examination of its effect on soil water retention and gas transport. The impact of PL biochar on soil wettability was examined with the water drop penetration test and contact angle measurements - performed on the biochar, a sassafras sandy loam soil, and a mixture of the biochar and soil. PL biochar was often hydrophobic; however, it could be rendered hydrophilic when mixed with deionized water at solid to liquid ratios of 1:20 and 1:200 for 24 hours. GCFID analysis of the eluent indicated leaching of organic compounds, which had a negligible effect on air-water interfacial tension. Capillary pressure saturation relationships were compared between soils with and without biochar and these results are reported.

59

Phosphorus Input, Crop Responses and Soil Phosphorus Accumulation in Vegetable Fields of China

Yan Zhengjuan, Liu Pengpeng, Li Yuhong, Chen Qing*

College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian, Beijing 100193, China

*Corresponding author: Tel: +86 -10-62733822, Fax:+86-10-62731016, qchen@cau.edu.cn

High economic profit of vegetable production and the rapid development of animal husbandry stimulated high input of organic manure in vegetable production of China. Animal manure i.e. poultry and pig manures, with relative high P ratio in contrast to low vegetable P uptake ratio, were the main type manures in vegetable production, however, neither could excessive manure application reduce the applied rate of compound fertilizer, nor excessive P input through manure inhibit the selection of high proportion of phosphorus in the formula of compound fertilizers. In the literatures including approximate 40 survey reports, several field trials, it was found that the total average P input per season were 1306.5 (13.1 folds of crop uptake) and 268.1 kg P2O5/ha (4.7 folds of crop uptake), respectively, in greenhouse and open-field of the main vegetable regions of China. Organic P application accounted for 54.3% and 44.0% of the total P input, respectively. Consequently, excessive P input resulted in serious P surplus. In fact, P deficiency was the ―bottleneck‖ for converting cereal field to vegetable field, the threshold of adequate P supply (soil Olsen-P) in rootzone were generally 28.5 mg P/kg, however, the threshold in greenhouse vegetable was much higher than that in open-field production due to low temperature, soil diseases, salinity and high nutrient level etc. Very high P surplus led to high soil P accumulation in vegetable field (i.e. over several hundred of Olsen P in greenhouse fields), which might cause soil degradation and water body eutrophication. The key to efficient use of P nutrient in vegetable field is to improve the spatial availability of soil P. Besides the control of total P input, the rotation including legume/cereal crops and the promotion of root system were other biological and agronomic ways to increase P use efficiency.

Keywords: Phosphorus input; manure; surplus; Olsen-P; Soil phosphorus accumulation; vegetable field; rootzone control; spatial availability.