Redmond Water Quality Proposal Version 2depts.washington.edu/esrm311/Autumn 2014/Documents 2014 Au/0… · artificial and natural rainfall events. For the overall study, which included

FIELD TEST OF COMPOST AMENDMENT TO REDUCE NUTRIENT

RUNOFF

FINAL REPORT

prepared by:

Robert B. Harrison

Mark A. Grey

Charles L. Henry

Dongsen Xue

UNIVERSITY OF WASHINGTON

COLLEGE OF

FOREST RESOURCES

Ecosystem Science and Conservation Division

Box 352100

Seattle WA 98195

206 685 7463 voice

206 685 3091 FAX

May 30, 1997

prepared for:

Phil Cohen

Effect of Compost on P Runoff Final Report page

2

City of Redmond

Public Works

Redmond, WA 98052


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TABLE OF CONTENTS

TABLE OF CONTENTS ............................................................................................................... 3

EXECUTIVE SUMMARY ............................................................................................................ 4

INTRODUCTION AND PROJECT OVERVIEW ...................................................................... 5

SITE, METHODS AND MATERIALS ........................................................................................ 6

Site Description and Construction ....................................................................................... 6

Soil and Compost Analysis .................................................................................................... 6

Plot Establishment and Fertilization .................................................................................... 7

Storm Simulation ................................................................................................................... 8

Runoff Characterization and Collection .............................................................................. 8

Runoff Analysis ...................................................................................................................... 8

RESULTS AND DISCUSSION ..................................................................................................... 9

Soil and Compost Analysis .................................................................................................... 9

Storm Hydrology .................................................................................................................. 10

Water Chemistry .................................................................................................................. 10

Hydrology and Water Chemistry Assimilation ................................................................. 13

SUMMARY AND CONCLUSIONS ........................................................................................... 16

Summary of Results ............................................................................................................. 16

Implications of Results ........................................................................................................ 17

Future Directions ................................................................................................................. 18


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EXECUTIVE SUMMARY

This project looked at the use of compost as an amendment to Alderwood series soil to

increase water-holding capacity, reduce peak flow runoff, and decrease phosphorus in runoff.

Seven 8 ft. x 32 ft. beds were constructed out of plywood lined with plastic and filled with

Alderwood subsoil or mixtures of soil and compost. These beds were located at the College of

Forest Resources Center for Urban Horticulture at the University of Washington. Samples were

taken over the period from March 7 to June 9, 1995. Compost amendment had the following

effects on physical water properties:

* Water-holding capacity was about doubled with a 2:1 compost:soil amendment.

* Water runoff properties were improved with the compost amendment, with the compost-

amended soil showing greater lag time to peak flow at the initiation of a rainfall event and

greater base flow in the interval following a rainfall event.

Water chemistry (total P, soluble-reactive P and nitrate-N) was measured for a series of

artificial and natural rainfall events. For the overall study, which included fertilizer treatments, the

following results were observed:

Runoff from the compost-amended soil had 24% lower average total P concentration (2.05 vs.

2.54 mg/L) compared to the Alderwood soil that did not receive compost amendment.

Soluble-reactive P was 9% lower in the compost-amended soil (1.09 vs 1.19 mg/L) compared

to the Alderwood soil that did not receive compost amendment.

Nitrate-N was 17% higher in the compost-amended soil (1.68 vs 1.39 mg/L) compared to the

Alderwood soil that did not receive compost amendment.

The water flow data from several storm events was coupled with the nutrient concentration

data to generate fluxes of nutrients from the plots. Results of these studys were variable, with

compost-amended soils lower in total P runof than unamended. When totals of fluxes are

summed, the compost-amended soils showed the following:

* 70% less total P,

* 58% less soluble-reactive P and

* 7% less nitrate in runoff compared to runoff from the till-only soil.

Differences in fluxes were attributed more to the changes in water flux rates than to water

chemistry, but both accounted for the lowered P with compost amentment. The results of this

study point out the promise of the use of organic amendments for improving water-holding

capacity, runoff properties and runoff water quality of Alderwood soils converted to turfgrass

from future development. The variability of results indicate a need for larger-scale field

confirmation (with replicated plots) of the results from these constructed research plots. Ideally,

any future study would include a turf established with other common commercially-utilized

methods, such as the practice of placing sod directly onto glacial till soil.


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INTRODUCTION AND PROJECT OVERVIEW

The College of Forest Resources (CFR) examined the effectiveness of using compost as a soil

amendment to increase surface water infiltration to reduce the quantity and/or intensity of surface

and subsurface runoff from land development projects. In addition compost amendment was

evaluated for its ability to reduce the transport of dissolved or suspended phosphorous (P) and

nitrogen (NO3) from drainage waters for the City of Redmond. The goal was to evaluate options

for improving the quality of water reaching Lake Samammish, Bear Creek and the Sammamish

River. Currently, due to the wide distribution and inherent stability of till soils in the region, most

residential housing developments are sited on the Alderwood soil series, which is characterized by

a compacted subsurface layer that restricts vertical water flow. When disturbed (and particularly

when disturbed with cut and fill techniques as with residential or commercial development),

uneven water flow patterns develop due to restricted permeability. This horizontal flow of water

on the surface and subsurface contributes to excessive overland flow, especially during storm

events, and transport of dissolved and suspended particulates to surface waters.

Research has demonstrated compost's effectiveness in improving the soil physical properties

of porosity, continuity of macropores, and water holding capacity which directly influence soil-

water relationships. It is clear that compost's chemical properties can also be valuable in some

cases, such as in complexing potentially harmful trace metals including copper, lead, and zinc.

Under this premise, the CFR examined the effectiveness of using compost to increase stormwater

infiltration and water holding capacity of these glacial till soils. Additionally, the CFR examined

whether or not increasing the infiltrative and retentive capacity of glacial till soils (Alderwood

series) can increase the contact with and retention of P and N by soil absorptive mechanisms, and

the production of P and N in surface and subsurface runoff by unamended and amended soils

during rainfall events.

The CFR utilized the existing Urban Water Resource Center (UWRC ) project site at the

University of Washington's Center for Urban Horticulture (CUH) for conducting the study. The

CFR utilized the UWRC design of large plywood beds for containing soil and soil-compost

mixes. These beds were located at the College of Forest Resources Center for Urban Horticulture

at the University of Washington. Water was supplied from a nearby existing water supply system

and used to simulate actual rainfall conditions. Simulated rainfall events of varying intensity were

scheduled to characterize infiltration rate, quantity of water flowing overland and subsurface,

quantity of water leaving study plots, and water quality leaving study plots. Samples were taken

over the period from March 7 to June 9, 1995.

The following paper describes the site, methods, results, and potential implications of these

studies.


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SITE, METHODS AND MATERIALS

Site Description and Construction

What was done. Working with the UWRC, the CFR utilized the existing site and associated

facilities at the University of Washington CUH. The system includes two different (different

sites) Alderwood till soils that were transported to the site, and several mixtures of the till soils

and compost mixtures readily available in the Seattle area. These mixtures include two control till

soils, a 2:1, 3:1 and 4:1 mixture (soil:compost by volume) of Cedar Grove fine compost:till soil, a

2:1 Cedar Grove coarse compost:till soil mixture, and a 2:1 GroCo compost:till soil mixture.

Figure M-1 shows the plot layout and treatments for the site. The soil and compost for this

study was mixed on an asphalt surface with a bucket loader and hauled and dumped into the plot

bays. The UWRC built the bays and installed the sprinkler and water monitoring system. A

system of collection buckets to allow sampling of runoff at intervals ranging from 15 minutes to

longer was installed as well.

Soil and Compost Analysis

Soil and soil/compost mixture samples were analyzed by the CFR analytical labs for the

following parameters:

1) total C,

2) total N,

6) bulk density,

7) particle density,

3) gravimetric water holding capacity (field capacity) moisture,

4) volumetric water holding capacity (field capacity) moisture,

5) total porosity,

8) particle size analysis, and

9) soil structure.

Samples were collected in August, 1994 from plot 1 (unamended Alderwood soil 1) and plot 2

(2:1 Cedar Grove fine compost:Alderwood soil 1). Analysis results are located in Appendix

Table 1a. These were characterized for all of the above properties. Samples were also collected in

December, 1994, but due to extremely wet conditions, it was not always possible to characterize

samples for all of the above properties.

Total C and N were determined using an automated CHN analyzer since they were considered

to be the primary measures of soil productivity in these soils. Bulk density was estimated using a


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coring device of known volume (bulk density soil sampler). The core was removed, oven dried,

and weighed. Bulk density was calculated as the oven dry weight divided by the core volume.

Particle density was determined by using a gravimetric displacement. A known weight of soil or

soil/compost mixture was placed in a volumetric flask containing water. The volume of

displacement was measured and Particle density calculated by dividing the oven dry weight by

displaced volume.

Gravimetric water holding capacity was determined using a soil column extraction method

that approximates field capacity by drawing air downward through a soil column. Soil or

soil/compost mixture was placed into 50 ml syringe tubes and tapped down (not compressed

directly) to achieve the same bulk density as the field bulk density measured with coring devices.

The column was saturated by drawing 50 ml of water through the soil column, then brought to

approximate field capacity by drawing 50 ml of air through the soil or soil/compost column.

Volumetric water holding capacity was calculated by multiplying gravimetric field capacity by

the bulk density. Total porosity was calculated by using the following function:

total porosity = 1- bulk density

particle densit y( ) x 100% (eq. 1)

Particle size distribution was determined both by sieve analysis and sedimentation analysis for

particles less than 0.5 mm in size. Due to the light nature of the organic matter amendment,

particle size analysis was sometimes difficult, and possibly slightly inaccurate. Soil structure was

determined using the feel method and comparing soil and soil/compost mixture samples to known

structures.

Plot Establishment and Fertilization

Plots were planted to a commercial turfgrass mixture during the Spring, 1994 season.

Fertilizer was added to all plots during plot establishment in the Spring of 1994 (16-4-8 N-P2O5-

K2O) broadcast spread over the study bays at the rate recommended on the product label (0.005 lb

fertilizer/ft2). The initial application resulted in an application of 0.023 lb of elemental P as

orthophosphate per plot or 0.000087 lb P/ft2. This resulted in an application of 0.20 lb of

elemental N as ammonium and nitrate (undetermined distribution) per plot or 0.00080 lb N/ft2.

Due to the poor growth of the control plots, and in order to simulate what would have likely

been done anyway on a typical residential lawn, an additional application of 0.005 lb/ft2 was made

to control plots on May 25, 1995. This helped to establish grass over a larger proportion of the


8

surface, which was quite bare. The compost-amended plots never appeared to need fertilizer

following establishment, and thus fertilization wasn't necessary to establish turfgrass.

Storm Simulation

Both surface and subsurface runoff were collected following seven simulated rainfall events.

To create uniform antecedent runoff conditions, some storm events were quickly followed by

another event. Simulated rainfall was applied at total amounts ranging from 0.76 to 2.46 inches

equivalent per storm, and rates ranging from 0.29 to 0.63 in/hour (Table M-1). The total amounts

and rates of rainfall during artificial events was estimated by placing collection tins across and

along the length of the plots. The amounts of water in the tins was measured at regular intervals

during plot irrigation.

Runoff Characterization and Collection

Runoff amounts and rates were measured for 15 minute intervals by use of tipping bucket type

devices attached to an electronic recorder. Each tip of the bucket was calibrated for each site and

checked on a regular basis to give rates of surface and subsurface runoff from all plots. There

appears to have been some movement of surface flow along the junction between the plot

containers and soil or soil/compost during heavy surface flow events, particularly for the soil-only

plots. There were also several instances where tipping buckets stuck during high rates of water

flow. These were fairly easily noted visually and by the data on the recorder (Table M-1).

Runoff was collected from bucket tips during 36 separate intervals by placing a collection

bucket at the base of the tipping bucket during each simulated rainfall event. Anywhere from 1 to

7 samples were taken for each storm event with intervals ranging from 15 minutes to 191 hours

(Table M-2).

Runoff Analysis

Runoff was analyzed by the CFR analytical laboratory for the following chemical species:

1) Soluble-reactive P (SRP),

2) Acid-hydrolyzeable phosphorus (AHP)

3) total Phosphorus (TP),

4) soluble nitrate (NO3)


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All work was done in accordance with University of Washington analytical laboratory QA/QC

procedures.

RESULTS AND DISCUSSION

Soil and Compost Analysis

The total C, total N, bulk density, particle density, gravimetric water holding capacity (field

capacity) moisture, volumetric water holding capacity (field capacity) moisture, total porosity,

particle size analysis, and soil structure of Alderwood soil and soil/compost mixtures is given in

Appendix 1 for the August, 1994 and December, 1994 samplings. Results show large changes in

the chemistry and physical properties of the soil/compost mixtures due to the compost amendment

(Appendix 1a, Appendix 1b).

The terminology used in industry and science for compost and soil properties is somewhat

inconsistent, so it will be explained quickly how calculations were made. First, percentages can be

given as % by weight or % by volume. In this report, percent by weight uses an oven-dried basis

for calculation. Volumes can change depending on handling, storage, moisture content and other

factors. As a final note the density (volume per unit weight) for compost is usually much lower

(i.e. 0.2-0.3 g/cm3) than for soil (i.e. 1.0-1.4 g/cm

3), so a weight percent change from compost

amendment will usually be much lower than a volume unit change, and moisture capacity based

on volume may be much different than moisture capacity based on weight.

Total C and organic matter was enhanced, increasing from 0.2-0.3% C (0.3-0.5% organic

matter) to about 2.4-2.8% C by weight (4.1-4.8% organic matter) with the compost amendment.

Total N was also enhanced, increasing from 0.04-0.12% to about 0.17-0.27% with the compost

amendment. Gravimetric field moisture capacity increased significantly from 19-29% to 35%

with the compost amendment. Volumetric field moisture capacity was also increased from 24 to

37% by the addition of compost.

Total porosity was increased from 19 to 39%. It appears that the measurement of porosity

might have been poor for the unamended sites, since this is extremely low for a soil. Bulk

density was decreased from about 1.3-1.9 to 1.1-1.3 g/cm3. Particle density was decreased from

about 2.3-2.5 to 2.0-2.1 g/cm3. Particle size analysis was not greatly affected by the compost

amendment. Soil structure, which is not a quantitative property, was also not greatly affected by

compost amendment.

Thus, there was a generally beneficial effect of the compost amendment in regards to nutrient

content as well as soil physical properties known to affect water relations in soils.


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Storm Hydrology

There are significant effects of the compost amendment on water relations in these soils. For

instance, Figure R-1a to R-4b show results of four storm simulations for periods starting April 25,

May 11, May 15 and May 25, 1995. These simulated storms ranged in total amounts from 1.4 to

4.8 inches, and in rates from 0.29 to 0.47 inches per hour. Though other events were sampled and

measured, there were problems with the waterflow collectors, and data is not presented here.

The first storm simulation clearly shows the general results, which were consistent throughout

the study periods. For instance, Figure R-1a shows the rainfall, runoff (subsurface + surface

flow), and storage for the period starting 8:30 AM April 25, 1995. The Y axis is given in liters

(per 15 minute period), and the y axis hours from start of event. Following the start of the rainfall

event, there is an increased lag time before significant runoff occurs (Figure R-1a and R-1b). The

compost-amended plot continues to store higher rates and total amounts of water for a longer

period of time. Following cessation of rainfall inputs, there are higher rates of runoff for a longer

period of time. Quicker runoff response to rainfall events is the classic response of hydrology to

urbanization, and this is clearly illustrated in Figure R-1a and R-1b. The total storage is also

increased with the compost amendment, increasing from about 300 to 500 liters, and the field

capacity is also increased from about 250 to 400 liters.

Numerical characteristics of the response hydrology are summarized in Table R-1 for

Simulation 1. Following the start of rainfall onto the sites at the rate of about 0.3 in/hour, it takes

the control unamended plot 1 approximately 30 minutes to respond with runoff > 0.01 in/hour

from an initial flow of nearly zero. The compost-amended site takes 1.0 hour or nearly twice as

long to respond with flow > 0.01 in/hour. It takes 0.75 hours from the start of the rainfall

simulation for flow to become > 0.1 in/hour in the unamended soil, while it takes 1.75 hours for

the compost-amended soil to increase to that rate, an increase of 1 hour compared to the

unamended site. In order for the runoff to reach 90% of input rate, it takes nearly 2.0 hours for the

unamended site compared to 5.25 hours for the compost amended site, an increase of 3.25 hours

compared to the control. This is an intense storm and results for moderate storms would likely

show similar results.

Following the cessation of rainfall, it takes 0.75 hours for runoff in the unamended site to drop

to < 10% of the rate of input, where it takes 1.5 hours for the compost-amended site, an increase

of 0.75 hours. It takes 1.75 hours following the cessation of rainfall for runoff in the unamended

site to drop to <0.01 in/hour, while it takes 6.5 hours for the compost-amended site, an increase of

4.75 hours.


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Similar results are seen with the additional three sampling periods, with storms of lesser total

amounts, including one series of natural rainfall events (Figures R-2a to R-4b). Compost-

amended soils consistently had longer lag times to response, longer times to peak flows, higher

base flows, higher total storage, and smaller total runoff than unamended soils. This indicates that

compost-amended soils have better water-holding and runoff characteristics than unamended

Alderwood soils and streamflow characteristics would likely benefit from an amendment made to

Alderwood soils in the region.

Water Chemistry

Caveats. We believe it is important to start with a cautionary note in terms of directly

comparing the concentrations of unamended with compost-amended plots in terms of the practical

use of compost vs. inorganic fertilizers in a field situation to achieve a desired turf. If there is a

minimum standard of aesthetic for the turf for a given area of land, whether it is compost-

amended or not, it is apparent from the visual appeal of the sites at CUH that more inorganic

fertilizer will be applied in the unamended vs. the compost-amended Alderwood soils to achieve

the same visual appeal. Following planting, compost-amended plots developed a dark green color

quickly, and achieved 100% coverage much more rapidly than unamended plots. At the end of

this study, the compost-amended sites were much better aesthetically, with a darker green color

and no bare spots. No soil can be seen through the grass. There are many bare spots with exposed

soil in the plots that did not receive compost amendment. The rates of growth of turf were also

greater even after a considerable period of time. The visual appeal of the compost-amended sites

was much greater during the duration of the study, although all sites did grow grass.

However, when inorganic fertilizer was applied initially, it was applied equally at all sites

since there was nothing but bare ground initially, and in addition, the standard of aesthetic is not

quantitative. Over time, however, it was apparant that it would be very difficult to achieve the

same visual appeal with inorganic fertilizer applied to Alderwood soil only in comparison to the

compost-amended Alderwood soil. Unfortunately, this reduces the utility of this study in

evaluating a compost-amended site that would not receive inorganic P fertilizers. We clearly

needed a comparative study of equal visual appeal. This was not achieved, since the compost-

amended sites were clearly visually superior.

Overall range of solution concentrations. The average solution analysis concentrations of

samples are given Table R-2, with each individual sample analyzed given in Appendix 2, and

averages of each plot in Appendix 3. It is obvious that there is a great deal of variation in P and N

chemistry in runoff from these results. For instance, the average total P (TP) concentration for all

samples analyzed was 2.29 mg/l while the minimum P was 0.07 and the maximum 21.0 mg/l


12

(Appendix 2, Appendix 3 and Table R-2). This represents a high degree of variation (greater than

100x) in concentration. This is not wholly unexpected in a system such as the one studied with

treatments ranging from surface runoff with high water flow in a very infertile, unfertilized glacial

till soil to surface and subsurface runoff in soils freshly fertilized with soluble NPK fertilizers.

Basic conclusions are as follows

1) The high amount of variation (S.D. generally > 100%) seen in these results makes drawing

specific and consistent conclusions with statistical significance difficult.

2) It was also not possible to directly compare compost-amended with unamended plots

statistically (i.e. by ANOVA), since there are only two control plots at the CUH.

The soluble-reactive P (SRP) concentration for all samples analyzed was 1.14 mg/l while the

minimum P was 0.01 and the maximum 7.02 mg/l (Appendix 2, Appendix 3 and Table R-2),

indicating that the SRP was generally a little less than half of the total for all samples (SRP/TP

ration for all samples = 0.42). The average SRP concentration measured is considerably above the

Water Quality recommendations for freshwater according to WAC 173-201 (1992), which is

0.100 for flowing water not discharging directly into a lake or impoundment. There is no standard

for total phosphorus or nitrate. .

The NO3-N concentration averaged 1.54 mg/l while the minimum NO3-N was 0.17 and the

maximum 9.14 mg/l (Appendix 2, Appendix 3 and Table R-2). Thus, the variation of solution

NO3-N was also quite high, ranging nearly 100x in concentration.

Averages-comparison of amended vs. unamended. For overall averages, there was not a

great deal of difference between runoff collected from compost-amended and unamended plots.

For instance, runoff solutions had TP concentration averages of 2.54 mg/l in unamended vs. 2.05

mg/l for the compost-amended plots, indicating that overall, the amended sites had lower total P.

This was true for SRP as well, with runoff averaging 1.19 mg/l in unamended vs. 1.09 mg/l for the

compost-amended plots (Table R-2). The OP was higher in compost-amended soils, averaging

1.29 mg/l in unamended vs. 0.85 mg/l for the compost-amended plots.

Runoff solutions had NO3-N concentration averages of 1.39 mg/l in unamended vs. 1.68 mg/l

for the compost-amended plots, indicating that overall, the amended sites had higher NO3-N

(Table R-2).

Storm events-comparisons. Since the most direct comparisons that can be made are between

plot 1 (unamended Alderwood soil 1) vs. plot 2 (2:1 Cedar Grove fine compost:Alderwood soil

1), and between plot 5 (unamended Alderwood soil 2) vs. plot 6 (2:1 GroCo compost:Alderwood

soil 2), the plots of runoff concentrations vs. time are grouped comparing plot 1 with 2 and plot 5

with 6. Though there is a great deal of variation in the data, as mentioned earlier, there are some


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trends in total P concentrations with time. It is also clear that the fertilization treatment in May

that fertilization has an immediate effect on the P concentration of runoff from these sites.

Figure R-5 and Figure R-6 show TP vs. event number (from Table M-2) for Plot 1 and 2

surface and subsurface runoff. The concentrations for collection intervals 1-7 are relatively low,

but the concentration of the control unamended increases greatly following fertilization with

organic fertilizer, increasing to 14.2 for the surface and 18.0 for subsurface runoff (Figure R-5 and

Figure R-6) collected during the 05/27/95--09:00-12:20 interval. The total P concentrations

decrease gradually over the following 2 weeks of collection and return to about their original

baselines. The compost-amended plots, which neither needed nor received fertilizer, also had

increases in TP concentrations, probably associated with increase organic matter decompostition

and release of mineral nutrients.

By the end of the study, the total P concentrations of solutions collected from surface and

subsurface runoff from plot 1 and 2 were nearly the same (Figure R-6). High concentrations

appeared to be associated with the fertilization treatment of unamended plot 1, and the P in these

samples was highly soluble. For instance, 60% of the total P in the surface runoff from the

05/27/95--09:00-12:20 collection interval from plot 1 was SRP and nearly 40% of the P in the

subsurface runoff was SRP.

The TP concentrations in plot 5 (unamended Alderwood soil 2) and plot 6 (2:1 GroCo

compost:Alderwood soil 2) show results very similar to those for plot 1 and 2. For instance,

Figure R-7 shows TP vs. event number (from Table M-2) for Plot 5 and 6 surface and subsurface

runoff. The concentrations are lower then 5 mg/l until after the second fertilization of control

plots, and then it increases rapidly (maximum >20mg/l) for the control plot 5 for several sampling

periods after that. The concentrations drop rapidly and by sampling period 32, the concentrations

of total P are below 5 mg/l again.

Soluble-reactive P (SRP) is the most bioavailable fraction of P analyzed in this study. SRP

concentrations are lower than total P concentrations for all samples taken at the same time, and

also generally lower overall. When plots 1 and 5 are fertilized, the SRP also increases greatly in

the unamended plot, and generally decreases back to previous levels after several weeks (Figure

R-8). The same general pattern of response to fertilization is seen in plot 5 (unamended

Alderwood soil 2), compared to plot 6 (2:1 GroCo compost:Alderwood soil 2). Following the

second fertilization of unamended plots on May 2, SRP concentrations increase abruptly for plot

5, and then decrease after several weeks of elevated SRP concentrations. Overall, concentrations

of SRP are lower for the compost-amended vs. control plots (Figure R-8 and R-9).

Nitrate concentrations varied considerably in these studies and there was no clear pattern.

There was no apparent increase in Nitrate concentration following the second fertilization of the


14

control plots on May 25, either, which is unexpected. Apparently, the control plots are nitrogen

and not phosphorus-limited in fertility, such that an increase in the availability of nitrogen does

not necessarily increase the solubility since the plants and microbes in the soil retain that added

nitrogen, and do not allow it to mineralize to nitrate. This variability in nitrate concentration can

be seen in Figure R-10 and Figure R-11.

Hydrology and Water Chemistry Assimilation

The hydrology data and phosphorus and nitrogen data was combined to estimate loss of SRP,

total P and nitrate from plots for periods of time where the hydrology and chemistry data were

considered to be adequate to calculate flux (i.e. no problems with tipping buckets, and no

problems with overflow of nutrient-solution collectors). Early problems with hydrology preclude

the use of some data for hydrology (as indicated in Table M-1), and all storms were not adequately

sampled for chemistry. Collection periods for which adequate data are available includes the

collection periods from May 15-16, May 25-26, May 30-June 3, and June 6-10.

Data were merged by applying the concentration of the solution (in mg/liter) collected by the

runoff volume (in liters) for surface and subsurface collectors for each 15-minute increment of

time. The amount of nutrient that is lost from the plot in this runoff was then summed and plotted

over time. Since there were problems with estimating surface vs. subsurface runoff in volumes,

and solution collection was volume-weighted, no separation of nutrient loss from surface vs.

subsurface runoff was attempted. The estimated nutrient production is thus mg per plot, and these

units are used in Figure R-12 to R-15.

May 15-16 Sampling Period. The data from the May 15-16 sampling period shows that

following establishment of plots 5 and 6 to turfgrass during the winter and spring of 1994-1995,

the nutrient output is quite low (Figure R-12). For instance, for a 30 hour period starting 8:00 AM

on May 15, 1995, only 25 mg of SRP, 493 mg of total P, and 959 mg of nitrate were lost as runoff

from plot 5 (unamended Alderwood soil 2), and 320 mg of SRP, 684 mg of total P, and 780 mg of

nitrate were lost as runoff from plot 6 (2:1 GroCo compost:Alderwood soil 2), despite the 1.8 in

of rainfall applied to the sites, and the large production of runoff (Figure R3a and R-3b). In these

events, the SRP is almost 10 times as high for the compost-amended vs. unamended, but the total

P is comparable. This may indicate that much of the P from the control site is particulate (it was

noted that control sites had higher suspended matter), while from the compost site it is soluble.

These total amounts of P are relatively small compared to runoff from the events following

fertilization of the plots.


15

May 25-26 Sampling Period. The effect of the May 25 fertilization is readily apparent in the

measured runoff for the May 25-26 event (Figure R-13). Note that the runoff production scale for

these events is nearly 20 times that of the May 15-16 sampling event. A total of 5,200 mg vs.

1,900 mg of SRP was produced from the unamended plot 5 compared to the compost-amended

plot 6 (Figure R-13). A total of 12,600 mg vs. 3,200 mg of total P was produced from the

unamended plot 5 compared to the compost-amended plot 6 (Figure R-13). A total of 17,500 mg

of total P was added with the amendment of May 15, so this represents over 72% of the original

fertilizer amendment running off with the first storm on plot 5. Thus, it appears that the

unamended plot has very little ability to retain fertilizer P during an intense storm event. Less

obvious is the reason why the unamended plot 6 also increased P production. This increase was

much less than that seen in plot 5. Bruce Jensen offered some insight into a possible reason when

he noted that semi-wild Canada geese living in the area seem to love eating grass on the compost-

amended plots, while ignoring the unamended plots. During these feedings they also leave a

considerable amount of droppings, which probably have high amounts of soluble inorganic

nutrients associated with them. Unfortunately, these factors make the comparisons of these sites

suspect. An additional explanation that may be likely is the increased mineralization of organic

matter as the weather warms and organic matter decomposition rates (that release mineral P)

increase.

The runoff of nitrate was almost identical for site 5 vs. site 6 (Figure R-13), with 2,052 mg for

site 5 vs. 2,219 mg for site 6 produced during the storm events. Nearly 160,000 mg of N was

added with the fertilization amendment, but there does not appear to be a significant effect of this

amendment on nitrate. Thought the fertilizer was not analyzed and no comparison of ammonium

vs. nitrate was given, it is likely that most of the nitrogen was in an ammonium form. This could

have been produced in the runoff in high concentrations. Since there was no NH4 analysis done

on the samples, it is unknown if this actually did occur.

May 30-June 3 Sampling Period. Samples were collected over longer periods of time

starting at the end of May (Figure R-14). Sampling was conducted during a 120 hour period

starting 8:00 AM on May 31, 1995 on 1 (unamended Alderwood soil 1) plot 2 (2:1 Cedar Grove

fine compost:Alderwood soil 1). A total of 392 mg of SRP, 1405 mg of total P, and 1209 mg of

nitrate were lost as runoff from plot 1, while 466 mg of SRP, 849 mg of total P, and 1184 mg of

nitrate were lost as runoff from plot 2. Note that an increasing amount of the P in the unamended

plot is insoluble, and probably of the particulate form.

The data from this sampling period shows the nutrient P concentrations and total runoff

following the fertilization event are dropping quickly in the control plot. Remember that 72% of

the total P was lost during the first 30 hours following fertilization during the May 25-26


16

simulated storms, so there may not be much of the original P left in these sites. In the case of plot

6, the geese were still visiting the site during this time, and this may affect the results due to their

droppings, which contain high amounts of P.

June 3-10 Sampling Period. A long-term collection of runoff was conducted from June 3-10

(Figure R-15). Sampling was conducted during a 180 hour period starting 10:00 AM on June 3,

1995 on plot 1 (unamended Alderwood soil 1), and plot 2 (2:1 Cedar Grove fine

compost:Alderwood soil 1). A total of 40 mg of SRP, 94 mg of total P, and 468 mg of nitrate

were lost as runoff from plot 1, while 42 mg of SRP, 61 mg of total P, and 386 mg of nitrate were

lost as runoff from plot 2. Most of the production of P and N from the compost-amended plot was

during periods well after the artificial storm events, whereas most of the nutrient production from

the unamended plot was during or immediately following the storm event.

These data show that nutrient production has dropped considerably compared to the storms of

May. For the control plot which received an additional fertilizer amendment after establishment,

this would point at the loss of soluble P due to loss and adsorption following the fertilizer

addition. It is uncertain why the production is lowering in the compost-amended plots, but it may

be due to an increasing demand for available nutrients by the rapidly growing grass in a system

that is now more depleted of available nutrients. Unfortunately, the high amount of varibility and

lack of suitable replication of plots in this study make conclusions difficult.

It should be noted that the artificial storms utilized in these studies represent intense rainfall

events of 25-100 year return intervals. It would be expected that the differences between the till-

only soil and the compost-amended till soil would be greater at less-intense rainfall events, though

the peak rates of runoff of both are likely to be reduced.

SUMMARY AND CONCLUSIONS

Summary of Results

Nutrient production from sites was highly variable, but following intense leaching during the

winter of 1994 and spring of 1995, concentrations and total runoff of P was slightly higher from

compost-amended sites. Nitrate concentrations and runoff were about the same. However, there

was insufficient grass growth in unamended sites, even following an establishment fertilization, so

an additional fertilizer addition was made. The compost-fertilized site was very attractive and

needed no fertilization. In fact, the initial establishment fertilization probably wasn’t necessary

either based on studies of turfgrass growth in compost-amended soils without inorganic

fertilization at the University of Washington on similar soils. Following the fertilizer addition in


17

the control plots, 72% of the P fertilizer added immediately ran off the site during the first storm

following fertilization, resulting in a 200-fold increase in P runoff with a single storm. The

fertilizer did seem to increase the rate of grass growth, and nutrient concentrations rapidly

decreased over time in the control sites. The limited results available from these studies point out

the necessity of conducting a field study that incorporates sufficient repetitions, time, and

fertilization regimes that establish similar turfgrass. Unfortunately, a lot of effort was spent on

development of methods of conducting this study, since none like has been conducted previously.

The results of these studies clearly show that compost amendment alters soil properties known

to affect water relations of soils, including the water holding capacity, porosity, bulk density, and

structure, as well as increasing soil C and N, and probably other nutrients as well. Results also

show that compost amendments affect water runoff patterns during and following storm events,

and runoff of nutrients from unamended vs. amended sites. In all cases, compost amendment

increased the lag time of response of a soil runoff hydrograph to a storm event, increased the time

to peak flow, decreased the rapidity of drop of the hydrograph following cessation of the storm

event, and increased the "base flow" in the period following the storm event. The amendment

increased the peak storage and field capacity of plots nearly 100%, and reduced the total runoff

depending on the intensity and duration of the storm event (i.e. small storms = little or no runoff;

large storms = almost complete runoff). Following one storm with another showed that

antecedent conditions were very important in determining total runoff from a particular storm

event.

These observations were true of both the Cedar Grove and GroCo amendments. However, the

GroCo:soil 2 combination appeared to have a much higher water holding capacity than the Cedar

Grove:soil 1 mixture. This is probably due to the fact that the GroCo is made with biosolids, and

contains much more finely divided and decomposed organic matter as well as flocculants

designed to precipitate suspended material from water during the water treatment process. GroCo

amendment also had a more pronounced effect on increasing lag times and base flows.

Implications of Results

Nutrient runoff was affected by compost amendment, but primarily from the lowering of total

runoff amounts and not due to lowering of nutrient concentrations in runoff. Compost-amended

turfgrass was uniformly beautiful, and required little or no fertilization, which is a definite

positive aspect of compost amendment. The poor quality of the unamended plots would likely

have resulted in addition nutrient application, and when we did this, almost all of the P fertilizer

ran off with the next storm event. This resulted in much more nutrient runoff from sites not


18

amended with compost compared to compost-amended sites. This may actually be the biggest

benefit of compost amendment...lack of need for further lawn fertilization.

Application of compost material similar to that in this study would be possible by applying 4

inches of compost onto the surface of an Alderwood soil and tilling to a total depth of 12 inches,

including the compost amendment (8 inches into the soil). This mixing would probably need to

be thorough and deep to achieve the conditions of this study, and this is not likely to be possible

with most existing equipment. However, if the compost is well incorporated into the soil, most of

the benefits of amendment seen in this study would likely be seen from a field application.

The results of this study clearly show that compost amendment is likely an effective means of

decreasing peak flows from all but the most severe storm events following very wet antecedent

conditions. An added benefit of amendments is an increased base flow in antecedent conditions

following storm events. The increases in water holding capacity with compost amendment shows

that storms up to 0.8 inches total rainfall would be well buffered in amended soils and not result in

significant peak flows, whereas without the amendment a storm about 0.4 inches total rainfall

would be similarly buffered.

If a significant percentage of till soils disturbed were amended with compost in this manner, it

would have this positive effect on hydrology. The absolute amount depends on many factors, but

it is clear that compost amendment is an excellent means of retaining runoff on-site and reducing

the rate of runoff from all but the most intense storm events. The effect of compost amendment

on total runoff amounts during the wettest parts of the winter would likely be minimal on these

Alderwood soils since there is very little transpiration during the winter. However, during the

early fall and late spring seasons, the additional water-holding capacity of the compost-amended

soils would result in additional transpiration from the plots and possibly lowered need for

irrigation. Despite the lack of probable effect on total runoff during the winter season, the effect

on storm peak flows would clearly be beneficial.

Future Directions

The resources of this study were largely consumed figuring out how to get these sampling

systems to work. Although there will always be similar problems in such studies, a lot more

stands to be gained from additional work on the CUH sites. For instance, a range of medium-

intensity simulated storms needs to be run, and longer-term evaluations could be made since all

plots are likely to change in chemistry and structure over time. Two critical questions need to be

answered:

1) Is the compost amendment permanent?


19

2) Will the properties of the unamended site improve with time?

If these question could be answered utilizing these sites, the long-term effect of the amendment

could be evaluated.

In addition, a series of field trials would ideally be created, with the area of compost-amended

vs. unamended evaluated from runoff into a small catchment. Whether or not such a site exists is

not easily answered here, but such a test of the utilization of compost would be the ideal means to

test its effect on runoff quantity and quality. Ideally, any future study would include a turf

established with other common commercially-utilized methods, such as the practice of placing

sod directly onto glacial till soil.


20

Table M-1. Storm Simulation Summary characteristics†

Start Plots Start dur- Averagedate studied time ation depth Rate Comments¥

–– h –– –– in –– –– in/h ––April 26 1 & 2 930 8 2.46 0.31April 27 1 & 2 930 8 2.33 0.29

§ May 5 1 & 2 900 1.5 0.95 0.63 Plot 1 bucket overflowed§ May 6 1 & 2 1430 2 0.89 0.45

May 13 1 & 2 900 3 1.42 0.47 Natural storm on previous day

May 16 5 & 6 930 3 1.04 0.35 Gutters coveredMay 17 5 & 6 1000 2 0.76 0.38 Gutters covered

May 25 5 & 6 1200 6 2.06 0.34 Gutters coveredMay 26 5 & 6 1200 6 2.03 0.34 Gutters covered

§ May 28 1 & 2 900 6 1.90 0.32 Buckets stuck on both plots!!! Gutters covered

§ May 30 1 & 2 1000 6 1.85 0.31 Plot 1 bucket stuck???§ May 31 1 & 2 1000 6 1.87 0.31 Gutters covered

June 9 1 & 2 1000 3 Gutters covered

† data from Kyle Kolsti, UW Center for Urban Water Resources¥ hydrology data highlighted in italics had one or more problems and was deleted from consideration in the hydrology results section§ storm data not analyzed due to problems noted in "Comments"


21

Table M-2. Summary of Run Collection Times

Field Collector placed Collector taken Sampling durationRun On Off (hours)

1 03/07/95--10:30 03/15/95--09:00 1912 04/25/95--09:00 04/26/95--09:00 24.03 04/27/95--10:00 04/28/95--11:00 25.04 05/01/95--10:18 05/03/95--18:00 565 05/04/95--09:30 05/08/95--09:30 966 05/08/95--09:30 05/12/95--09:00 957 05/12/95--09:00 05/15/95--09:00 728 05/15/95--09:00 05/15/95--12:45 3.89 05/15/95--12:45 05/15/95--13:15 0.510 05/15/95--13:15 05/16/95--10:10 20.911 05/16/95--10:14 05/16/95--12:15 2.012 05/16/95--12:15 05/16/95--12:30 0.313 05/16/95--12:30 05/16/95--13:00 0.514 05/16/95--13:00 05/24/95--12:00 19115 05/24/95--12:05 05/25/95--11:30 23.416 05/25/95--11:45 05/25/95--15:20 3.617 05/25/95--15:30 05/25/95--18:06 2.618 05/25/95--18:06 05/25/95--18:21 0.219 05/25/95--18:21 05/26/95--21:15 26.920 05/26/95--21:15 05/26/95--21:30 0.321 05/26/95--21:30 06/03/95--10:10 18122 05/27/95--09:00 05/27/95--12:20 3.323 05/27/95--12:20 05/27/95--15:15 2.924 05/27/95--15:15 05/27/95--15:46 0.525 05/27/95--15:46 05/27/95--21:10 5.426 05/27/95--21:10 05/31/95--09:55 8527 05/31/95--10:00 05/31/95--16:30 6.528 05/31/95--16:30 06/03/95--10:10 6629 05/27/95--21:10 05/31/95--09:55 8530 05/31/95--10:00 05/31/95--16:30 6.531 05/31/95--16:30 06/03/95--10:10 6632 06/03/95--10:10 06/06/95--19:52 8233 06/06/95--19:52 06/09/95--10:00 6234 06/09/95--10:00 06/09/95--20:10 10.235 06/09/95--20:10 06/10/95--20:16 24.136 06/09/95--10:00 06/10/95--20:16 34.3


22

Table R-1. Hydrological characteristics of simulated rainfall

additionalhydrologic control compost lag with

characteristic unamended amended compost

––––––––– simulation 1, storm 1 –––––––––total input 2.33 in 2.46 in

rainfall rate 0.28 in/h 0.30 in/hrunoff > 0.01 in/hour 0.50 h 1.00 h 0.50 h

runoff > 0.1 in/hour 0.75 h 1.75 h 1.00 hrunoff rate > 90% input rate 2.00 h 5.25 h 3.25 hrunoff < 10% of input rate† 0.75 h 1.50 h 0.75 h

runoff < 0.01 in/hour 1.75 h 6.50 h 4.75 h––––––––– simulation 1, storm 2 –––––––––

total input 2.09 in 2.29 inrainfall rate 0.26 in/h 0.29 in/h

runoff > 0.01 in/hour 0.25 h 0.50 h 0.25 hrunoff > 0.1 in/hour 0.50 h 1.00 h 0.50 h

runoff rate > 90% input rate 0.75 h 1.25 h 0.50 hrunoff < 10% of input rate† 0.75 h 1.50 h 0.75 h

runoff < 0.01 in/hour 1.75 h >2.00 h


23

Table R-2. Summary statistics for solution chemistry analyses

analyzed in laboratory derived measures

total Acid Occluded Organic

reactive digested Total Nitrate- P P

P P P nitrogen (ACP-TP) (TP-ACP)

Treatment SRP ACP TP NO3-N OCP OP

–––––––––––––––– average concentration (mg/l) –––––––––––––––––––average (treated and control) 1.14 1.51 2.29 1.54 0.24 1.06

control unamended 1.19 1.56 2.54 1.39 0.25 1.29compost amended 1.09 1.46 2.05 1.68 0.22 0.85

control unamended lower 1.04 1.22 2.07 1.57 0.13 0.99compost amended lower 1.22 1.59 2.43 1.75 0.24 1.11

control unamended upper 1.40 2.06 3.17 1.16 0.43 1.71compost amended upper 0.91 1.25 1.53 1.57 0.19 0.45


24

8'

32'

control soil 1

soil 1

soil 1

soil 1

2:1 CG fine

2:1 CG coarse

4:1 CG fine

soil 2control

soil 2

soil 2

2:1 GroCo

3:1 CG fine

weather station

1 2 4 876

5

3

2'

8'

1'

16'

2'

5'

9'

4'

Detail of Soil Sampling Scheme

Figure M-1. University of Washington Center for Urban Water Resources compost amendment research site layout.


25

-40

0

40

80

120

160

0 5 10 15 20 25 30 35

Figure R-1a. Comparison of intervals of rainfall, runoff, surface flow, subsurface flow and storage volumes for plot 1 (control) and 2 (amended) for sequential rainfall events starting April 25, 1995.

Inte

rval

flo

ws

(liter

s/h

ou

r)

Plot 1 Control unamended

-40

0

40

80

120

160

200

0 5 10 15 20 25 30 35

Hours from start of event

Inte

rval

flo

ws

(liter

s/h

ou

r)

Plot 2 Compost amended

start 8:30 AM April 25, 1995


Rainfall

Runoff

Surface flow

Subsurface flow

Storage


26

Figure R-1b. Comparison of total rainfall input, cumulative runoff, and net storage for plot 1 (control) and 2 (amended) for sequential rainfall events starting April 25, 1995.


0

100

200

300

400

500

600

0 5 10 15 20 25 30 35

To

tal

sto

rag

e (l

iter

s)

compost-amended

control unamended

To

tal

flu

x (

lite

rs)

0

500

1000

1500

2000

2500

3000

control unamended

compost-amended

total runoff

control unamended

compost-amended

total rainfall

control unamended

compost-amended

rainfall storage

start 8:30 AM April 25, 1995


Water balance for storm event

Rainfall Runoff

unamended amended unamended amended

–––––– liters –––––– –––––– liters ––––––

total liters per plot 2,780 2,997 2,491 2,658

percent runoff 90 89

percent retention 10 11

inches storm event 4.60 4.96

inches runoff 4.12 4.40

inches retention 0.48 0.56


27

0

20

40

60

80

100

120

140

160

0 5 10 15 20 25

-60

-40

-20

0

20

40

60

80

100

120

0 5 10 15 20 25

Figure R-2a. Comparison of intervals of rainfall, runoff, surface flow, subsurface flow and storage volumes for plot 1 (control) and 2 (amended) for rainfall event starting May 11, 1995.





Inte

rval

flo

ws

(lit

ers/

ho

ur)

Inte

rval

flo

ws

(lit

ers/

ho

ur)

start 2:00 PM May 11, 1995

Rainfall

Runoff

Surface flow

Subsurface flow

Storage


28

0

200

400

600

800

1000

1200

0 5 10 15 20 25

0

100

200

300

400

500

600

0 5 10 15 20 25

control unamended

compost-amended

total runoff

control unamended and compost-amended

total rainfall

control unamended

compost-amended

rainfall storage

To

tal

sto

rag

e (l

iter

s)T

ota

l fl

ux

(li

ters

)

Figure R-2b. Comparison of total rainfall input, cumulative runoff, and net storage for plot 1 (control) and 2 (amended) for sequential rainfall events starting May 11, 1995.


Rainfall Runoff


–––––– liters –––––– –––––– liters ––––––

total liters per plot 1,081 1,081 740 639






start 2:00 PM May 11, 1995




29

0.0

10.0

20.0

30.0

40.0

50.0

0 5 10 15 20 25 30

0.0

10.0

20.0

30.0

40.0

50.0

0 5 10 15 20 25 30

Rainfall

Runoff

Surface flow

Subsurface flow

Storage






Inte

rval

flo

ws

(liter

s/hour)

Inte

rval

flo

ws

(liter

s/hour)

start 8:00 AM May 15, 1995


30


Rainfall Runoff


–––––– liters –––––– –––––– liters ––––––

total liters per plot 1,041 1,081 798 347






0

200

400

600

800

1000

1200

0 5 10 15 20 25 30

0

100

200

300

400

500

600

700

800

0 5 10 15 20 25 30

start 8:00 AM May 15, 1995

control unamended

compost-amended

total runoff

control unamended

compost-amended

rainfall storage

Tota

l st

ora

ge

(liter

s)T

ota

l fl

ux (

lite

rs)





total rainfall


31

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

0 5 10 15 20 25 30 35 40

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

0 5 10 15 20 25 30 35 40

Rainfall

Runoff

Surface flow

Subsurface flow

Storage






Inte

rval

flo

ws

(liter

s/h

our)

Inte

rval

flo

ws

(liter

s/h

our)

start 11:00 AM May 25, 1995


32


Rainfall Runoff


–––––– liters –––––– –––––– liters ––––––

total liters per plot 2,432 2,432 1,749 1,214






0

500

1000

1500

2000

2500

0 5 10 15 20 25 30 35 40

0

200

400

600

800

1000

1200

1400

0 5 10 15 20 25 30 35 40

start 11:00 AM May 25, 1995

control unamended

compost-amended

total runoff

control unamended

compost-amended

rainfall storage

Tota

l st

ora

ge

(liter

s)T

ota

l fl

ux (

lite

rs)





total rainfall


33

T

ota

l P

con

cen

trati

on

(m

g/L

)

Figure R-5. Total P concentration of plot 1 (control unamended) and plot 2 (compost-amended).

Event number (see Table R-1 for sampling durations).

0

5

10

15

20

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36

subsurface

surfacePlot 1 control unamended

Plot 2 compost amended

Treatments

subsurface

surface


34

Figure R-6. Total P concentration following fertilization of plot 1 (control unamended) and plot 2 (compost-amended).


Tota

l P

con

cen

trati

on

(m

g/L

)

subsurface



Treatments

subsurface

surface

0

5

10

15

20

21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


35

T

ota

l P

con

cen

trati

on

(m

g/L

)

0

5

10

15

20

25

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


Figure R-7. Total P concentration of plot 5 (control uname nded) and plot 6 (compost-amended).

subsurface



Treatments

subsurface

surface

plots 1 & 5 fertilized


36

S

olu

ble

Rea

ctiv

e P

ho

sph

ate

(m

g/L

)

0

2

4

6

8

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

Figure R-8. Soluble reactive phosphate concentration of plot 1 (control unamended) and plot 2 (compost-amended).



subsurface



Treatments

subsurface

surface


37

0

2

4

6

8

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

So

lub

le R

eact

ive

Ph

osp

ha

te (

mg/L

)


Figure R-9. Soluble reactive phosphate concentration of plot 5 (control unamended) and plot 6 (compost-amended).


subsurface



Treatments

subsurface

surface


38

Figure R-10. Total NO3-N concentration following fertilization of plot 1 (control unamended) and plot 2 (compost-amended).


Tota

l N

O3-N

con

cen

trati

on

(m

g/L

)

0

1

2

3

4

5

6

7

8

9

10

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


subsurface



Treatments

subsurface

surface


39

0

1

2

3

4

5

6

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

To

tal N

O3

-N c

on

cen

tra

tio

n (

mg/L

)


Figure R-11. Total NO3-N concentration following fertilization of plot 5 (control unamended) and plot 6 (compost-amended).


subsurface



Treatments

subsurface

surface


40

0

50

100

150

200

250

300

350

0 5 10 15 20 25 30

0

100

200

300

400

500

600

700

0 5 10 15 20 25 30

0100200300400500600700800900

1000

0 5 10 15 20 25 30

Time from start of first storm event (hours)


till soil only

till with compost amendment


Figure R-12. Measured runoff of total P, SRP and NO3-N from May 15-16 storm simulation for plots 5 and 6

till soil only


till soil only


To

tal

Ph

osp

ho

rus

flu

x

(mg

per

plo

t)S

olu

ble

Ph

osp

hat

e fl

ux

(m

g p

er p

lot)

Nit

rate

-N f

lux

(m

g p

er p

lot)

493

684

25

320

959

780

start 8:00 AM May 15, 1995

start 8:00 AM May 15, 1995

start 8:00 AM May 15, 1995


41

Nitra

te-N

flu

x

(mg p

er p

lot)


0

500

1000

1500

2000

2500

0 5 10 15 20 25 30 35 40

2,219

2,052

Figure R-13. Measured runoff of total P, SRP and NO3-N from May 25-26 storm simulation for plots 5 and 6

till soil only


start 11:00 AM May 25, 1995

0

1000

2000

3000

4000

5000

6000

0 5 10 15 20 25 30 35 40

5,189

1,880


Solu

ble

Pho

sph

ate

flux

(m

g p

er p

lot) till soil only


start 11:00 AM May 25, 1995

Tota

l P

ho

sph

oru

s fl

ux

(m

g p

er p

lot)

0

2000

4000

6000

8000

10000

12000

14000

0 5 10 15 20 25 30 35 40

12,657

3,257


till soil only


start 11:00 AM May 25, 1995


42

050

100150200250300350400450500

0 20 40 60 80 100 120

0

200

400

600

800

1000

1200

1400

1600

0 20 40 60 80 100 120

0

200

400

600

800

1000

1200

1400

0 20 40 60 80 100 120


till soil only


Figure R-14. Measured runoff of total P, SRP and NO3-N from May 30-June 3 storm simulation for plots 1 and 2.

till soil only


till soil only


To

tal

Ph

osp

ho

rus

flu

x

(mg

per

plo

t)S

olu

ble

Ph

osp

hat

e fl

ux

(m

g p

er p

lot)

Nit

rate

-N f

lux

(m

g p

er p

lot)

1405

849

392

466

1209

1184

Time from start of first storm event (hours)start 8:00 AM May 31, 1995

start 8:00 AM May 31, 1995


43

05

10

15202530

354045

0 20 40 60 80 100 120 140 160 180

0102030405060708090

100

0 20 40 60 80 100 120 140 160 180

050

100150200250300350400450500

0 20 40 60 80 100 120 140 160 180

94

61

40

42

468

386



till soil only



Figure R-15. Measured runof f of total P, SRP and NO3-N from June 6-10 storm simulation for plots 1 and 2

till soil only


till soil only


To

tal

Ph

osp

ho

rus

flux

(m

g p

er p

lot)

Solu

ble

Ph

osp

hate

flu

x

(mg

per p

lot)

Nit

rate

-N f

lux

(mg

per p

lot)

start 10:00 AM June 3, 1995




44

Appendix 1a. S um mary of soil an alys is data for fie ld pl ots . Sampl ed Au gust, 1994. (note that sample s for the August analysis were taken a ccording to Figure M-1 sam pling sche me).

Sampled in August, 1994Field Field Particle Size Analysis soil structure by

total total Capacity Capacity Total Bulk Particle < 2mm parts percentage visual and feelPlot and rep C N g/g ml/ml Porosity Density Density 2-0.02 0.02-0.005 0.005-0.002 <.002 method

% by weight % % % g/cm3 g/cm3 % % % %

Plot 1, rep 1 0.2 0.12 20 28 48 1.37 2.63 76.3 12.5 1.3 10.0 single grain / weak granularPlot 1, rep 2 0.3 0.14 18 22 52 1.22 2.54 76.3 11.3 3.8 8.8 single grain / weak granularPlot 1, rep 3 0.3 0.13 18 21 56 1.15 2.64 76.3 12.5 1.3 10.0 single grain / weak granularPlot 1, rep 4 0.3 0.15 18 24 42 1.38 2.39 75.0 13.8 3.8 7.5 single grain / weak granularPlot 1, rep 5 0.2 0.12 16 20 49 1.28 2.53 76.3 13.8 2.5 7.5 single grain / weak granularPlot 1, rep 6 0.3 0.10 16 22 46 1.35 2.50 76.3 13.8 1.3 8.8 single grain / weak granularPlot 1, rep 7 0.5 0.12 16 20 52 1.23 2.54 76.3 13.8 1.3 8.8 single grain / weak granularPlot 1, rep 8 0.2 0.11 28 35 50 1.26 2.54 76.3 12.5 1.3 10.0 single grain / weak granularPlot 2, rep 1 2.2 0.26 37 41 47 1.12 2.12 73.8 12.5 6.3 7.5 single grain / weak granularPlot 2, rep 2 2.6 0.27 39 39 56 0.98 2.23 77.5 10.0 5.0 7.5 single grain / weak granularPlot 2, rep 3 3.4 0.28 34 33 52 0.95 1.97 77.5 10.0 5.0 7.5 single grain / weak granularPlot 2, rep 4 2.7 0.25 32 36 49 1.14 2.25 77.5 10.0 5.0 7.5 single grain / weak granularPlot 2, rep 5 2.8 0.24 33 37 47 1.14 2.13 77.5 10.0 5.0 7.5 single grain / weak granularPlot 2, rep 6 2.0 0.22 32 35 53 1.07 2.29 73.8 12.5 6.3 7.5 single grain / weak granularPlot 2, rep 7 2.5 0.30 46 49 48 1.06 2.03 76.3 10.0 6.3 7.5 single grain / weak granularPlot 2, rep 8 4.5 0.36 27 30 44 1.14 2.05 73.8 12.5 6.3 7.5 single grain / weak granular

amended average 2.8 0.27 35 37 50 1.08 2.13 75.9 10.9 5.6 7.5no compost average 0.3 0.12 19 24 49 1.28 2.54 76.1 13.0 2.0 8.9


45

Appe ndix 1b. S um mary of soil an alys is data for f ie ld pl ots . Sampl e d De ce m be r, 1994.

Caution: sampling of these sites was done under less than ideal conditions when the soils was highly saturated.This could easily lead to compaction of these sandy-textured soils when sampling for bulk density and affect any porosity-related analys is

Sampled December 13, 1994Field Field Particle Size Analysis soil structure by

total total Capacity Capacity Total Bulk Particle < 2mm parts percentag e visual and feelSample designation C N g/g ml/ml Poros ity Density Density 2-0.02 0.02-0.005 0.005-0.002 <.002 method

% % % % % g/cm3 g/cm3 % % % %plot 1 BD, control 0.2 0.02 19 1.97 2.33 single grain / weak granular

plot 2 BD, CGfine2:1 3.1 0.20 41 1.16 1.99 single grain / weak granularplot 3 BD, CGcoarse2:1 3.0 0.23 38 1.45 2.05 single grain / weak granular

plot 3 Grab, CGcoarse2:1 3.1 0.23 46 82 9 2 7 single grain / weak granularplot 4 Grab, CGfine4:1 1.8 0.13 24 72 18 7 3 single grain / weak granular

plot 5 Grab, control 0.1 0.05 29 82 12 3 3 single grain / weak granularplot 6 Grab, Groco2:1 1.2 0.06 35 78 15 4 3 single grain / weak granular

plot 7 Grab, CGfine3:1 2.2 0.16 34 79 15 5 1 single grain / weak granularamended average 2.4 0.17 35 39 1.30 2.02 82 12 3 3

no compost average 0.2 0.04 29 19 1.97 2.33 78 14 5 4


46

Appendix 2. Laboratory analyses for water samples analyzed in the study.

analyzed in laboratory derived measurestotal Acid Occluded Organic

Date reactive digested Total Nitrate- P Pfield upper (U) analysis P P P nitrogen Ac-P - TR-P T-P - Ac-P

Sample plot lower (L) run† reported TR-P Ac-P T-P NO3-N Oc-P Or-P

––––––––––––––––––––––––––––– mg/L ––––––––––––––––––––––––––––––––––––––––– 1-L-0 1 L 0 3/10/95 0.48 0.51 0.75 n.d. 0.03 0.241-L-1 1 L 1 3/27/95 0.06 0.07 0.23 n.d. 0.00 0.161-L-2 1 L 2 5/3/95 0.07 i.s. 0.07 n.d. i.s. i.s.1-L-3 1 L 3 5/3/95 0.03 i.s. 0.07 n.d. i.s. i.s.1-L-4 1 L 4 5/3/95 0.06 i.s. 0.11 n.d. i.s. i.s.1-L-5 1 L 5 5/15/95 0.06 0.19 0.80 0.79 0.12 0.621-L-6 1 L 6 5/15/95 0.03 0.06 0.15 1.00 0.03 0.101-L-7 1 L 7 5/15/95 0.03 0.06 0.10 0.81 0.03 0.041-L-22 1 L 22 6/9/95 7.02 7.11 18.02 1.30 0.09 10.911-L-23 1 L 23 6/9/95 3.61 3.81 4.49 1.43 0.20 0.681-L-24 1 L 24 6/9/95 2.49 2.71 3.42 1.18 0.22 0.711-L-25 1 L 25 6/9/95 0.61 0.83 1.17 1.40 0.23 0.331-L-27 1 L 27 6/9/95 3.12 3.57 4.53 1.09 0.45 0.961-L-28 1 L 28 6/9/95 0.22 0.35 0.37 1.07 0.12 0.021-L-30 1 L 30 6/9/95 0.08 0.14 0.21 2.39 0.06 0.071-L-31 1 L 31 6/9/95 0.07 0.36 0.53 9.14 0.28 0.171-L-32 1 L 32 6/9/95 0.13 0.16 0.35 0.52 0.03 0.191-L-33 1 L 33 6/12/95 0.12 0.13 0.24 4.35 0.01 0.111-L-36 1 L 36 6/12/95 0.14 0.17 0.30 2.42 0.03 0.131-U-1 1 U 1 3/27/95 i.s. i.s. 0.76 n.d. i.s. i.s.1-U-2 1 U 2 5/3/95 0.03 i.s. 0.22 n.d. i.s. i.s.1-U-3 1 U 3 5/3/95 0.08 i.s. 0.42 n.d. i.s. i.s.1-U-4 1 U 4 5/3/95 0.05 i.s. 0.38 n.d. i.s. i.s.1-U-5 1 U 5 5/15/95 0.06 0.08 0.19 0.81 0.02 0.111-U-6 1 U 6 5/15/95 0.11 0.12 0.29 0.81 0.01 0.17


47





––––––––––––––––––––––––––––– mg/L ––––––––––––––––––––––––––––––––––––––––– 1-U-7 1 U 7 5/15/95 0.03 0.06 0.23 0.95 0.03 0.171-U-22 1 U 22 6/9/95 5.53 5.68 14.24 1.57 0.15 8.571-U-23 1 U 23 6/9/95 3.45 4.14 5.69 0.69 0.69 1.551-U-24 1 U 24 6/9/95 2.84 3.30 4.06 1.31 0.47 0.751-U-27 1 U 27 6/9/95 1.54 1.76 2.33 2.42 0.22 0.571-U-28 1 U 28 6/9/95 0.20 1.35 2.03 0.60 1.16 0.68

1-U-30.31 1 U 30-31 6/9/95 2.20 2.35 2.87 0.49 0.16 0.521-U-32 1 U 32 6/9/95 0.14 0.35 0.40 0.44 0.20 0.051-U-33 1 U 33 6/12/95 0.11 0.14 0.26 1.42 0.03 0.121-U-36 1 U 36 6/12/95 0.17 0.33 0.44 1.05 0.16 0.112-L-1 2 L 1 3/27/95 0.19 0.19 0.57 n.d. 0.01 0.382-L-2 2 L 2 5/3/95 0.36 i.s. 0.43 n.d. i.s. i.s.2-L-3 2 L 3 5/3/95 0.43 i.s. 0.52 n.d. i.s. i.s.2-L-4 2 L 4 5/3/95 0.48 i.s. 0.53 n.d. i.s. i.s.2-L-5 2 L 5 5/15/95 0.41 0.43 0.54 0.87 0.02 0.112-L-6 2 L 6 5/15/95 0.30 0.38 0.55 0.91 0.08 0.172-L-7 2 L 7 5/15/95 0.24 0.45 0.62 1.01 0.21 0.172-L-22 2 L 22 6/9/95 1.00 1.25 1.51 1.71 0.25 0.252-L-23 2 L 23 6/9/95 0.53 0.75 0.79 1.40 0.23 0.032-L-24 2 L 24 6/9/95 0.46 0.67 0.94 1.23 0.22 0.272-L-25 2 L 25 6/9/952-L-26 2 L 26 6/9/95 0.40 0.75 1.01 1.07 0.35 0.252-L-27 2 L 27 6/9/95 0.55 0.69 0.80 1.84 0.14 0.122-L-28 2 L 28 6/9/95 0.52 0.77 0.83 1.93 0.25 0.062-L-29 2 L 29 6/9/95 0.36 0.55 0.61 0.74 0.19 0.06


48





––––––––––––––––––––––––––––– mg/L ––––––––––––––––––––––––––––––––––––––––– 2-L-30 2 L 30 6/9/95 0.37 0.46 0.60 2.16 0.09 0.142-L-31 2 L 31 6/9/95 0.30 0.40 0.51 1.99 0.10 0.112-L-32 2 L 32 6/9/95 0.28 0.33 0.46 7.82 0.05 0.142-L-33 2 L 33 6/12/95 0.56 0.58 0.62 2.83 0.02 0.042-L-36 2 L 36 6/12/95 0.35 0.41 0.46 0.43 0.07 0.052-U-1 2 U 1 3/27/95 i.s. i.s. 0.81 n.d. i.s. i.s.2-U-2 2 U 2 5/3/95 0.45 i.s. 1.11 n.d. i.s. i.s.2-U-3 2 U 3 5/3/95 0.15 i.s. 0.30 n.d. i.s. i.s.2-U-4 2 U 4 5/3/95 0.20 i.s. 0.57 n.d. i.s. i.s.2-U-5 2 U 5 5/15/95 0.24 0.31 0.32 0.89 0.07 0.012-U-6 2 U 6 5/15/95 0.03 i.s. 0.26 0.80 i.s. i.s.2-U-7 2 U 7 5/15/95 0.11 0.21 0.32 0.92 0.11 0.112-U-22 2 U 22 6/9/95 2.32 2.79 3.85 1.43 0.47 1.062-U-23 2 U 23 6/9/95 0.58 0.73 0.77 1.17 0.15 0.042-U-24 2 U 24 6/9/95 0.52 0.69 1.03 1.30 0.17 0.352-U-27 2 U 27 6/9/95 1.20 1.40 1.53 1.21 0.20 0.132-U-28 2 U 28 6/9/95 0.31 0.52 0.53 0.56 0.20 0.02

2-U-30.31 2 U 30-31 6/9/95 0.25 0.33 0.46 0.55 0.08 0.132-U-32 2 U 32 6/9/95 n.s . n.s . n.s . n.s . n.s . n.s .2-U-33 2 U 33 6/12/95 0.64 0.78 0.81 3.64 0.14 0.032-U-36 2 U 36 6/12/95 0.35 0.37 0.55 2.24 0.02 0.193-L-1 3 L 1 3/27/95 0.59 0.63 0.93 n.d. 0.04 0.313-L-4 3 L 4 5/3/95 0.32 i.s. 0.69 n.d. i.s. i.s.3-L-32 3 L 32 6/9/95 1.04 1.28 1.37 1.03 0.24 0.103-U-1 3 U 1 3/27/95 0.54 0.59 1.69 n.d. 0.04 1.10


49





––––––––––––––––––––––––––––– mg/L ––––––––––––––––––––––––––––––––––––––––– 3-U-4 3 U 4 5/3/95 0.59 i.s. 1.76 n.d. i.s. i.s.3-U-32 3 U 32 6/9/95 0.60 0.63 0.85 ND 0.03 0.225-L-1 5 L 1 3/27/95 0.19 0.20 0.44 n.d. 0.01 0.245-L-4 5 L 4 5/3/95 2.56 i.s. 3.30 n.d. i.s. i.s.5-L-8 5 L 8 5/15/95 0.01 0.10 0.27 1.29 0.09 0.175-L-9 5 L 9 5/15/95 0.01 0.10 0.41 1.15 0.09 0.315-L-10 5 L 10 5/15/95 0.05 0.14 0.89 1.42 0.09 0.755-L-11 5 L 11 5/15/95 0.11 0.12 0.28 1.38 0.02 0.165-L-12 5 L 12 5/15/95 0.12 0.30 0.43 1.74 0.18 0.145-L-13 5 L 13 5/15/95 0.08 0.10 0.83 1.16 0.02 0.735-L-14 5 L 14 5/15/95 0.14 0.14 0.81 1.39 0.00 0.665-L-15 5 L 15 6/9/95 1.48 1.58 2.60 1.05 0.10 1.025-L-16 5 L 16 6/9/95 4.01 4.31 7.08 1.25 0.31 2.775-L-17 5 L 17 6/9/95 1.96 2.21 3.01 0.82 0.25 0.805-L-18 5 L 18 6/9/95 2.05 2.36 3.51 0.54 0.31 1.155-L-19 5 L 19 6/9/95 1.68 1.86 2.53 0.51 0.18 0.685-L-20 5 L 20 6/9/95 4.86 5.42 12.86 0.94 0.56 7.445-L-32 5 L 32 6/9/95 0.46 0.50 0.69 0.78 0.05 0.195-L-34 5 L 34 6/12/95 0.15 0.19 0.33 1.42 0.03 0.145-L-35 5 L 35 6/12/95 0.22 0.29 0.33 1.27 0.07 0.045-U-1 5 U 1 3/27/95 0.09 0.10 0.36 n.d. 0.01 0.265-U-4 5 U 4 5/3/95 0.16 i.s. 0.26 n.d. i.s. i.s.5-U-8 5 U 8 5/15/95 0.03 0.24 0.66 1.38 0.21 0.43

5-U-11.14 5 U 11–14 5/15/95 0.03 0.51 0.99 0.95 0.49 0.485-U-15 5 U 15 6/9/95 1.53 1.87 2.94 2.69 0.34 1.07


50





––––––––––––––––––––––––––––– mg/L ––––––––––––––––––––––––––––––––––––––––– 5-U-16 5 U 16 6/9/95 6.22 8.64 21.00 2.46 2.42 12.365-U-17 5 U 17 6/9/95 2.62 3.11 4.33 0.17 0.49 1.225-U-18 5 U 18 6/9/95 5.95 6.19 15.49 0.29 0.24 9.305-U-19 5 U 19 6/9/95 n.s . n.s . n.s . n.s . n.s . n.s .5-U-20 5 U 20 6/9/95 3.49 5.20 5.85 0.97 1.71 0.655-U-32 5 U 32 6/9/95 0.86 0.97 1.17 1.08 0.11 0.205-U-34 5 U 34 6/12/95 0.19 0.49 0.54 0.82 0.31 0.055-U-35 5 U 35 6/12/95 0.15 0.39 0.42 2.11 0.24 0.036-L-1 6 L 1 3/27/95 2.17 2.26 13.78 n.d. 0.09 11.516-L-4 6 L 4 5/3/95 0.08 i.s. 0.42 n.d. i.s. i.s.6-L-8 6 L 8 5/15/95 1.27 2.01 3.19 2.77 0.75 1.186-L-9 6 L 9 5/15/95 1.47 2.13 3.31 2.58 0.66 1.186-L-10 6 L 10 5/15/95 2.01 2.21 3.76 2.36 0.20 1.556-L-11 6 L 11 5/15/95 0.88 0.93 1.53 1.93 0.05 0.606-L-12 6 L 12 5/15/95 1.85 1.99 2.31 1.67 0.14 0.326-L-13 6 L 13 5/15/95 1.74 2.42 3.50 1.95 0.68 1.086-L-14 6 L 14 5/15/95 2.87 2.89 5.48 2.38 0.02 2.596-L-15 6 L 15 6/9/95 2.52 2.54 4.51 1.36 0.02 1.976-L-16 6 L 16 6/9/95 0.88 1.07 1.78 1.94 0.19 0.716-L-17 6 L 17 6/9/95 0.56 0.82 1.12 0.52 0.26 0.306-L-18 6 L 18 6/9/95 1.91 2.08 2.85 0.34 0.17 0.776-L-19 6 L 19 6/9/95 3.71 3.93 5.63 0.44 0.22 1.706-L-20 6 L 20 6/9/95 4.81 5.02 11.49 2.02 0.20 6.476-L-21 6 L 21 6/9/95 4.83 6.83 11.58 1.32 2.00 4.766-L-32 6 L 32 6/9/95 1.97 2.04 2.12 0.52 0.06 0.09


51





––––––––––––––––––––––––––––– mg/L ––––––––––––––––––––––––––––––––––––––––– 6-L-34 6 L 34 6/12/95 2.15 2.45 2.60 1.94 0.30 0.156-L-35 6 L 35 6/12/95 2.41 2.51 2.67 2.78 0.10 0.166-U-1 6 U 1 3/27/95 0.64 0.67 1.53 n.d. 0.03 0.876-U-4 6 U 4 5/3/95 0.77 i.s. 2.07 n.d. i.s. i.s.6-U-8 6 U 8 5/15/95 0.63 1.23 2.34 2.73 0.60 1.11

6-U-11.14 6 U 11–14 5/15/95 0.85 0.99 1.31 1.94 0.15 0.326-U-15 6 U 15 6/9/95 1.76 2.14 2.71 5.04 0.39 0.576-U-16 6 U 16 6/9/95 1.56 1.86 2.60 0.55 0.30 0.746-U-17 6 U 17 6/9/95 1.41 1.79 2.53 0.23 0.38 0.746-U-18 6 U 18 6/9/95 0.72 0.92 1.12 2.76 0.20 0.206-U-19 6 U 19 6/9/95 0.91 1.07 3.06 0.94 0.16 1.986-U-20 6 U 20 6/9/95 n.s . n.s . n.s . n.s . n.s . n.s .6-U-32 6 U 32 6/9/95 1.71 1.98 2.08 1.51 0.27 0.106-U-34 6 U 34 6/12/95 2.40 2.65 2.85 1.17 0.25 0.206-U-35 6 U 35 6/12/95 4.08 4.13 4.28 1.34 0.06 0.15

† see Table R-1 for explanation of ru ns; runs th at co ntain more th an one n umber are continu ous thro ugh several run s


52

Appendix 3. Summary statistics f or solution chemistry analyses




P P P nitrogen Ac-P - TR-P T-P - Ac-P

Sample plot U/L TR-P Ac-P T-P NO3-N Oc-P Or-P

–––––––––––––––– average concentration (mg/l) –––––––––––––––––––control 1 L 0.97 1.26 1.89 2.06 0.12 0.96control 1 U 1.10 1.64 2.18 1.05 0.27 1.11

amended 2 L 0.42 0.57 0.68 1.86 0.14 0.15amended 2 U 0.52 0.81 0.88 1.34 0.16 0.20amended 3 L 0.65 0.95 1.00 1.03 0.14 0.20amended 3 U 0.58 0.61 1.43 n.d. 0.04 0.66control 5 L 1.12 1.17 2.26 1.13 0.14 1.02control 5 U 1.78 2.52 4.50 1.29 0.60 2.37

amended 6 L 2.11 2.56 4.40 1.70 0.34 2.06amended 6 U 1.45 1.77 2.37 1.82 0.25 0.63

–––––––––––––––– minimum concentration (mg/l) ––––––––––––––––––control 1 L 0.03 0.06 0.07 0.52 0.00 0.02control 1 U 0.03 0.06 0.19 0.44 0.01 0.05



–––––––––––––––– maximum concentration (mg/l) –––––––––––––––––control 1 L 7.02 7.11 18.02 9.14 0.45 10.91control 1 U 5.53 5.68 14.24 2.42 1.16 8.57




53

Appendix 3. Summary statistics f or solution chemistry analyses




P P P nitrogen Ac-P - TR-P T-P - Ac-P

Sample plot U/L TR-P Ac-P T-P NO3-N Oc-P Or-P ––––––––––––––––––––– standard deviation ––––––––––––––––––––––

control 1 L 1.8 2.0 4.2 2.3 0.1 2.7control 1 U 1.7 1.9 3.6 0.6 0.3 2.4

amended 2 L 0.2 0.3 0.3 1.8 0.1 0.1amended 2 U 0.6 0.8 0.9 0.9 0.1 0.3amended 3 L 0.4 0.5 0.3 0.1 0.1amended 3 U 0.0 0.0 0.5 n.d. 0.0 0.6control 5 L 1.5 1.6 3.2 0.3 0.1 1.8control 5 U 2.3 2.9 6.8 0.9 0.8 4.3


–––––––––––––––– number of samples analyzed –––––––––––––––––––control 1 L 19 16 19 14 16 16control 1 U 15 12 16 12 12 12

amended 2 L 19 16 19 15 16 16amended 2 U 14 10 15 11 10 10amended 3 L 3 2 3 1 2 2amended 3 U 3 2 3 n.d. 2 2control 5 L 18 17 18 16 17 17control 5 U 12 11 12 10 11 11

amended 6 L 19 18 19 17 18 18amended 6 U 12 11 12 10 11 11