Soil & Water Management - Bruce Atherton, NRCS - Bioreactors to Mitigate Nutrient Discharge in Field Drainage

Bruce Atherton, P.E.Agricultural EngineerNRCS, Ankeny, Iowa

Agribusiness Showcase & ConferenceFebruary 7, 2012

Subsurface Drainage & Water Quality

Subsurface Drainage and Water Quality

Review effects of agricultural subsurface drainage Review nutrient levels in streams, especially nitrates Review strategies to reduce nitrate export from field to

stream and the effectiveness of each Look at NRCS cost-share and payment rates Reminder of Conservation Compliance

BENEFITS OF CROPLAND DRAINAGE

Remove excess water Improve crop rooting

environment Enhanced soil warming Improved trafficabilty

More timely field operations Earlier planting date

Reduce soil compaction Increase nitrogen availability

and efficiency Save energy Reduce runoff and erosion Reduce flooding potential Increase yields and income

Bars Indicate Relative Crop Yield Increase with Drainage Improvement

Background Shading Indicates Reduction in Year-to-Year Variability in Crop Yields

Subsurface Drainage in Iowa

Estimates for Iowa

36 million acres of land

23 million acres of row crops

9 million acres with artificial subsurface drainage

(742,500 miles at 100 foot spacing)

6 million acres in 3000+ organized drainage districts

Source: Baker, et al. 2004. Subsurface Drainage in Iowa and the Water Quality Benefits and Problem

Environmental Effects of Subsurface Drainage

• Compared to undrained agricultural land, improved subsurface drainage can (at the field level)• Reduce the peak runoff rate 15 to 30% • Reduce the total surface runoff that leaves the site 29 to 65% • Reduce sediment losses by 16-65%• Reduce the loss of phosphorus up to 45% • Reduce the loss of soil-bound nutrients 30 to 50% • Increase NO3-N losses

Source: Zucker, L.A. and L.C. Brown (Eds.). 1998. Agricultural Drainage: Water Quality Impacts and Subsurface

Drainage Studies in the Midwest. Ohio State University Extension Bulletin 871. The Ohio State University.

Change in Nitrate Concentrations in Midwest Rivers

Source: Goolsby, D.A. and W.A. Battaglin. 2000. Nitrogen in the Mississippi Basin-Estimating Sources and Predicting Flux to the Gulf of Mexico

In the 20th century there were changes in:

• land use / cropping

• fertilizer use

• improved drainage

River Nitrate Levels(Concentration is important for drinking water suppliers)

Source: Mary Skopec, Ph.D., IOWATER & Stream Monitoring Coordinator, Iowa DNR. Personal Communicatoin, December 2011.

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EPA Drinking Water Standard Trendline

2002 estimated nitrate/nitrite loading:

960,000 metric tons(12th highest in 22 yrs)

Gulf Hypoxia(Load is also important)

Gulf Hypoxia Action Plan Nutrient Reduction Goals

Current (2003-2007) average hypoxic zone is 14,644 km2

Goal is 5,000 km2 hypoxic zone (5-yr average) Strategy is a target nutrient reduction of:

45% reduction in total nitrogen flux 45% reduction in total phosphorus flux

(Measured against average 1980 - 1996 levels)

Source: Draft Hypoxia 2008 Action Plan, November 9, 2007

Gulf Hypoxia Changes in Nutrient Loading

Annual loads from 2001-2005 time period(Measured against average 1980 - 1996 levels) 21% reduction in total nitrogen flux 12% increase in total phosphorus flux

Current load estimates by source Point sources - 22% of N loads, 34% of P loads Point sources - higher share than earlier estimates


Gulf Hypoxia Nutrient Reduction Strategies

USDA will place additional emphasis on conservation practices with high potential for reducing nutrient loadings, such as

nutrient management cover crops siting of wetlands on-farm drainage water management


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Corn-Soybean Rotation 150/160 lb-N/acre Application Rate

Variability in Drainage, Nitrate Concentration and Nitrate Loss

Source: Slide courtesy of Matt Helmers, Ph. D., ISU Extension Agricultural EngineerData based on a research study at Gilmore City, Iowa

Nutrient Reduction Strategies

• Nutrient management• Cropping changes• Cover crops

• Constructed Wetlands• Bioreactors

• Drainage design • Drainage water management

Photo Courtesy of IDALS

Photo by Lynn Betts, USDA-NRCSPhoto by Lynn Betts, USDA-NRCS

Photo courtesy The Ohio State University

Photo by Bruce Voights, Wright SWCD

Agronomic Strategies

Nutrient management Reduced tillage Cropping changes Cover crops

Nutrient management effects

Some NO3-N loss will occur even with no N application Increased soil NO3-N resulting from large N applications appears

to be buffered by large amount of NO3-N naturally present in soil In one Iowa study, NO3-N concentrations were not higher for fall

applied N Split N applications during the growing season have not shown

large or consistent reduction in NO3-N concentrations in drainage water

Source: Baker, et al. 2004. Subsurface Drainage in Iowa and the Water Quality Benefits and Problem. In: Proceedings of the Eighth International Drainage Symposium, March 21-24, 2004.

Impact of Nitrogen Application Rate


Nitrate-N Concentration as a Function of Nitrogen Application


Impact of Nitrogen Application Rate

~15% Reduction


Tillage Effects

Study of four tillage systems in NW Iowa• NO3-N concentrations in moldboard- and chisel-plowed fields

averaged 30-50% higher than for flat and ridged no-till fields. (C-Sb rotation)

• In continuous corn, losses from no-till fields were about the same as for plowed field because of increased flow.

Differences may be due to:• Change in volume and route of infiltration• Difference of N mineralization


Crop Effects

NO3-N concentration in shallow saturated soils

• 0.2 mg/L – native grass in RR right-of-way• >10 mg/L – row crop field < 20’ away

Studies in Iowa showed much reduced NO3-N concentrations for alfalfa, CRP, and small grains

A Minnesota study showed an 90% reduction in NO3-N leaching losses with CRP

Another study of alfalfa or alfalfa/grass vs. C-Sb rotation showed 96% reduction in NO3 lost in subsurface drains


Cover Crops Effects

Iowa study, C-Sb rotation, rye planted each year Canisteo and Nicollet soils in Boone Co.

• Significantly reduced subsurface drainage water NO3 concentrations and NO3 loads in all 4 years

• 4-year average reduction in NO3 concentration was 59%

• 4-year average reduction in NO3 load was 61%

• Corn yield reduction in 2002 but not 2004

• No Soybean yield reduction

Source: Kaspar et al. 2007. Rye Cover Crop and Gamagrass Strip Effects on NO3 Concentration and Load in Tile Drainage. J. Environ. Qual. 36:1503-1511.









Constructed Wetlands

Remove nitrogen through denitrification• Studies show average total nitrogen removal ranges

from 37% to 65%

Source: Appleboom, T.W., and J.L. Fouss. 2004. Methods for removing Nitrate Nitrogen from Agricutlural Draiange Waters: A Review and Assessment. ASABE Paper No. 062328. St. Joseph, MI: ASABE.

Photo by Bruce Atherton, Iowa NRCS

Constructed Wetlands Iowa Conservation Reserve Enhancement Program (CREP) Research at Iowa State University has shown that wetlands

meeting CREP requirements will remove 40-90% of the nitrate received

The area of these wetlands is 0.5 % to 2% of the contributing watershed area

Photo by Bruce Atherton, Iowa NRCS

Drainage Water TreatmentWoodchip Bioreactor

Source: Christianson, Laura and Matthew Helmers. 2011. Woodchip bioreactors for nitrate in agricultural drainage. Iowa State University Extension Publication. PMR 1008. Available at: https://store.extension.iastate.edu/ItemDetail.aspx?ProductID=13691.

Design by Richard Cooke, University of Illinois

Nitrate-nitrogen is removed from the drainage water by denitrification inwhich nitrate is converted to mostly nitrogen gas

https://store.extension.iastate.edu/ItemDetail.aspx?ProductID=13691

https://store.extension.iastate.edu/ItemDetail.aspx?ProductID=13691

Bioreactors

Several Bioreactors have been installed in Iowa, many with financial assistance from the Iowa Soybean Association

Bioreactors are eligible for NRCS funding assistance (EQIP)

Nitrate reduction varies from 10% to 90+%, averages ~35-40%

Still in research & demonstration stage










Golden Rule of Drainage

Only release the amount of water necessary to insure trafficable conditions for field operations and to provide an aerated crop root zone

any drainage in excess of this rule likely carries away nitrate and water that is no longer available for crop uptake - Attributed to Wayne Skaggs

Precision drainage?

Drain Design Modifications

Decrease drainage intensity• Wider spacing• Shallower depths

Drainage Water Management

Source: Appleboom, T.W., and J.L. Fouss. 2004. Methods for removing Nitrate Nitrogen from Agricutlural Draiange Waters: A Review and Assessment. ASABE Paper No. 062328. St. Joseph, MI: ASABE.

Conventional Drainage

Free Outlet

Hydrological modifications of subsurface (tile) drainage systems to reduce subsurface drainage from Iowa’s tile landscapes:-

Subsurface Drainage Types

Shallow Drainage Controlled Drainage

Subsurface (tile) Drainage System : Representation in DRAINMOD

Water table

Impermeable layer

Drain Drain

Evapotranspiration Evapotranspiration

Subsurface drainage Subsurface drainageVertical seepage

Surface runoffSurface runoff

Lateral seepage

Lateral seepage

Precipitation Precipitation

Shallow Drainage

Minnesota Research

15% reduction in nitrate loss As high as 40% on some plots 15-40% water conserved No yield changes observed

Source: Gary Sands, P.E.

Nitrate Loss & Drain Depth

Source: Illinois Drainage Guide (online). http://www.wq.uiuc.edu/dg/

Conventional Drainage

Free Outlet

Hydrological modifications of subsurface (tile) drainage systems to reduce subsurface drainage from Iowa’s tile landscapes:-

Subsurface Drainage Types

Shallow Drainage Controlled Drainage

Drainage Water Management(Controlled Drainage)

Since 1984, over 4000 water control structures affecting about 400,000 acres have been installed in North Carolina.

Conservative estimates based on results of research indicate that these systems, properly managed, reduced N losses to coastal streams and estuaries by 4 million pounds annually.

Research in North Carolina (1990-2010) showed: Controlled drainage plots on both sites experienced significant (10.4%) corn yield

increases compared to the free drainage plots. No significant change in wheat yields was observed under CD. Soybean yield increased in all years.

Research in the Midwest has failed to show significant yield increases

Source: C.A. Poole et al. 2011. The Effects of Drainage Water Management on Crop Yields in Eastern North Carolina. ASABE Paper No. 1111599. St. Joseph, MI: ASABE.

The water level control device place in a tile line. The area impacted is a function of the slope of the field. The flatter the field the greater the area impacted.

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Raised Water Table

Riser Boards (Adjustable)

Tile

Drainage DesignThe Influence of Slope

Image courtesy of Agri Drain Corp.

Typical layout of subsurface drainage system

Image courtesy of Agri Drain Corp.

Idealized drain layout for drainage water management (DWM)Drain laterals laid on contour to maximize area in management zone

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Drain Watertable

Seasonal Water Table Management

Source: Gary Sands, P.E.

Planting Lower water

table for trafficability

Growing season Raise to hold water, but manage for plant health

Harvest Lower water

table if needed for trafficability

Non-growing season Raise to near the surface

Seasonal Water Table Management

Source: Illinois NRCS

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Managing the Water TableISU Research – Crawfordsville, Iowa

Source: Helmers, Matt. July 2010. Personal Communication

Outlet Setting

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Source: Helmers, Matt. July 2010. Personal Communication

Managing the Water TableISU Research – Crawfordsville, Iowa

DWM Example of Area Controlled

Water Control structure set just below 1128 contour.

Shaded area includes the area between 1128 and 1130 contours.


Drainage Water Management - Drain layout at a Minnesota site

Source: Agriculture Drainage Management Drainage Coalition; http://www.admcoalition.com/

Drainage Water ManagementSoutheast Iowa Research

Drainage water management through controlled or shallow drainage significantly reduced overall drainage by 30 to 40%

Nitrate load reduction closely follows the drainage reduction Implies the nitrate load can be reduced 30-40%

Water table response was quick with drawdown to tile depth within 2 to 3 days after significant rain events

Source: Helmers, et al. 2010. Water Table Response to Drainage Water Management in Southeast Iowa ASABE Paper No. IDS-CSBE100138. St. Joseph, MI: ASABE.

Wetland-Reservoir-Subirrigation (WRSIS)

Source: http://www.ars.usda.gov/Research/docs.htm?docid=14999&page=9Accessed January 18, 2008.

A WRSIS is a water management system to collect subsurface drainage and runoff, treat this water in a constructed wetland, and store the treated water in a reservoir for subsequent use for subirrigation during drier parts of the growing season.

http://www.ars.usda.gov/Research/docs.htm?docid=14999&page=9

WRSIS Benefits


Potential benefits of this system inlcude:(1) enhanced crop yields, (2) reduced offsite release of nutrients, pesticides, and sediment, (3) additional wetland vegetation and wildlife habitat, (4) more carbon sequestration in soil, and possibly,(5) decreased flooding potential downstream

Marsh Foundation WRSIS site in Van Wert Co., Ohio


WRSIS Yield Benefits


As of 2006, at 3 sites, 1996-2006 WRSIS subirrigated yield increases for corn and soybeans, respectively, were :

30.8% and 26.0% during drier growing seasons

13.3% and 6.9% during near average to wetter growing seasons

18.1% and 13.0% overall.

Schematic of a WRSIS site in Fulton Co., Ohio


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Schematic of nitrogen transformation and retention in a riparian buffer.

Source: Slide provided by Dan B. Jaynes, USDA-ARS-National Laboratory for Agriculture and the EnvironmentJanuary 2012.

Question:

Could reconnecting tile flow to riparian buffers remove substantial amounts of nitrate before it reaches surface waters?




Induced interflow

b) Enhanced denitrificationa) Enhanced uptake

c) Surface discharge d) Channel slumping



Saturated Buffer Summary

•1st year shows re-saturating riparian buffers can remove all the nitrate that is diverted into them.•We were able to divert about 60% of the flow from a tile draining about 50 ac of field•The cost of the practice is comparable to other N removal practices•Practice shows potential of preventing > 11 million lbs of N from entering IA streams each year•Currently expanding study by re-saturating 3 new sites in each of IA, IL, and IN (CIG – ADMC).


Summary

Approach Nitrate Reduction

Limitations

Nutrient management

0 – 15% Most reductions already obtained

No-till vs. conventional (C-Sb)

30 – 50% Acceptance

No-till vs. conventional (C-C)

~ 0% No advantage

Alfalfa/Grass/CRP vs. row crop

~ 90% Economics

Rye cover crop > 50% Additional expense, tripsAllelopathic effects on cornTimeliness at harvest

Summary (Cont)

Approach Nitrate Reduction Limitations

Constructed Wetlands

37 – 65% Topography

Bioreactors 10 – 90% ExpenseMore research needed

Drain intensity (design)

~15% up to 40% TopographyNew systems only


~ 50% (but maybe not in Iowa)

TopographySeasonal flow

Saturated Buffers ~60% (one site, one year) Limited Research

NRCS Financial Assistance

Cover Crop Practice Code 340 Crops including grasses, legumes, and forbs planted for seasonal

cover and other conservation purposes.

EQIP payment rate for 2012 is about $19.99 (oats) to $27.08 (rye) per acre

Rates may be higher for historically underserved persons and for initiative projects.


Bioreactor Practice Code 747 A structure containing a carbon source (wood chips) to treat

subsurface drainage outflow.

EQIP payment rate for 2012 is about $4000 each Rates may be higher for historically underserved persons and for

initiative projects.


Drainage Water Management Plan Conservation Activity Plan - 130 Plan is completed by a certified Technical Service Provider (TSP)

who is paid by the farmer Each plan is for one field Plan includes

A topographic survey of the field Location of the control structures the controlled zones Description of when and how to adjust the stop boards

EQIP payment rate for 2012 is about $1400 - $1600 per plan Rates may be higher for historically underserved persons and for



Structure for Water Control Practice Code 587 Installation of a water control structure in a drainage system (for

example, an Agridrain inline control structure) Payment is for each structure EQIP payment rate for 2012 is about $1000 for a structure 10” or

smaller EQIP payment rate for 2012 is about $1400 for a structure 12” or

larger Rates may be higher for historically underserved persons and for



Drainage Water Management Practice Code 554 This is the annual management of the control structures in a field

with a drainage water management plan Farmer adjusts stop boards and records settings

EQIP payment rate for 2012 is about $5.05 per acre

Rates may be higher for historically underserved persons and for initiative projects.

Mississippi River Basin Healthy Watersheds Initiative

Mississippi River Basin Healthy Watersheds Initiative

13 state effort

$80,000,000 per year for 4 years (authorized)

In Iowa there are 13 projects in 6 watersheds Fiscal year 2010 - $1.35 million for 45 contracts

Fiscal year 2011 - $6 million obligated for 155 contracts

Farm Bill Compliance

• When producing an annual agricultural commodity, USDA program participants must apply an approved conservation system that meets the substantial reduction or no substantial increase definitions, (see NFSAM, Part 512, Subpart A, Paragraph 512.01(e).)

• To maintain eligibility, participants must also certify that they have not produced crops on converted wetlands after December 23, 1985, and did not convert a wetland after November 28, 1990, to make agricultural production possible.

• NRCS will determine whether land contains areas that are classified as a wetland type.

Ref: National Food Security Act Manual, Fourth Edition, January 2008. 510.02, 510.12

http://directives.sc.egov.usda.gov/M_180_512_A_01.htm

Wetland Delineation Process(abridged)

Producer requests wetland determination via form AD-1026

• Or, NRCS responds to a whistleblower complaint

NRCS personnel determine if sampling units in a field , either cropland or non-cropland, meet the definition of wetlands

• Hydrophytic vegetation, hydric soils, hydrology

The Food Security Act wetland type is determined. If site is altered by drainage, an exemption may be granted. Labels may include:

• W – Wetland or NW – Non-wetland

• PC – Prior converted cropland

• FW – Farmed wetland

• FWP – Farmed wetland pasture

Farmer is notified of decision and has a right to appeal

Allowable Maintenance Actions

Allowable Maintenance

(1) Maintenance or improvement of drainage systems is allowable on all prior converted (PC) cropland as long as adjacent wetlands are not adversely affected.

(2) On farmed wetland (FW) and farmed wetland pasture and hayland (FWP), manipulation that exceeds the scope and effect of the original manipulation will result in ineligibility for USDA program benefits.

Ref: National Food Security Act Manual, Fourth Edition, January 2008. 516.12

Contact information:Bruce Atherton, P.E. Agricultural EngineerUSDA-NRCS1513 N. Ankeny Blvd., Ste. 3Ankeny, IA 50023-4167Ph: 515-964-1883 Fax: 515-964-8613Email: [email protected]

USDA is an Equal Opportunity Provider and Employer

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Soil & Water Management - Bruce Atherton, NRCS - Bioreactors to Mitigate Nutrient Discharge in Field Drainage