The Effect of Compost Application and Plowing on
Phosphorus RunoffCharles S. Wortmann
Department of Agronomy and HorticultureNutrient Management for Soil Productivity
and Water Quality Protection
Phosphorus in fresh surface waters
P is often most limiting nutrient to the growth of aquatic vegetation
Agricultural land is a major source of P♦ Greater losses with high soil test P, e.g.
where much manure has been applied♦ Manure P excretion is increasing as diet P
increases due to feeding by-products
Several field factors affect P loss♦ Site factors, e.g. soil test P and P application♦ Transport factors, e.g., erosion and runoff
Relative importance of total P vs. dissolved P entering waters♦ Aquatic vegetation uses dissolved P♦ Much runoff P is not dissolved P, but may
become available with time♦ Need to be concerned about total P loss
Phosphorus in fresh surface waters
Research at the UNL – ARDC
1998 - 2006
Objectives
Determine the effects on management practices on runoff, sediment loss, and P loss
During the years of application, 1999-2001 The residual effects during 2001 to 2004 Residual effects during 2004 to 05 and
effect of plowing extremely high P soil Residual effects of 2006-07 and effects of
vegetative barriers
Effects during the years of application
Composted feedlot manure was applied annually for 3 years to meet the N need of irrigated corn
Two compost types were used♦ Low P compost: 670 lb/A P applied ♦ High P compost: 1025 lb/A P applied
The plots were disked
Compost effect on soil test P (Bray-P1)
Depth, inches
Hi-P compost
Lo-P compost
No compost
0-2 779 380 16
2-4 307 154 9
4-8 53 37 10
8-12 38 26 10
Results: Runoff and erosion, 99-01 Runoff volume and sediment loss were greatly reduced by compost application during the years of application.
Volume of runoff during 1999 to 2001
0
0.5
1
1.5
2
2.5
3
3.5
Compostapplied
Nocompost
Low-Pcompost
High-Pcompost
Ru
no
ff, a
cre
-in
ch
es
Sediment loss during 1999 to 2001
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Compostapplied
Nocompost
Low-Pcompost
High-Pcompost
Se
dim
en
t lo
ss
, t/A
Runoff and erosion: 01-04
The residual effect of compost applied 1-3 yr previously was reduced runoff and sediment loss.
Residual effect on runoff loss
0
0.5
1
1.5
2
2.5
3
3.5
Low Pcompost
High Pcompost
No compost
Ru
no
ff, A
cre
-in
ch
es
Residual effect on sediment loss
0
0.05
0.1
0.15
0.2
0.25
0.3
Low Pcompost
High Pcompost
No compost
Se
dim
en
t lo
ss
, T/A
c
Runoff and erosion: 04-05
The residual effect of compost at 4 – 5 yr after application♦ Slightly reduced runoff♦ Greatly reduced erosion
The effect of plowing♦ Reduced runoff♦ Slight increase in
sediment loss
Runoff volume
0
0.2
0.4
0.6
0.8
1
1.2
No compostapplied
Compostapplied
Compostapplied,plowed
Ru
no
ff, a
cre-
inch
Sediment loss
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
No compostapplied
Compostapplied
Compostapplied, plowed
Sed
imen
t lo
ss, t
/acr
e
P loss during years of application: ‘99-01
Compost application
1. P concentration in runoff much higher.
2. P loss was increased.
Bio-available P concentration, 1999-2001
0
0.5
1
1.5
2
2.5
Compostapplied
Nocompost
Low-Pcompost
High-Pcompost
P c
on
cen
trat
ion
, pp
m
Bio-available P (FeO test) loss
0
0.5
1
1.5
2
2.5
3
3.5
Compostapplied
Nocompost
Low-Pcompost
High-Pcompost
Ava
ilab
le P
loss
, lb
/A
01-04. Runoff P concentrations were very high 1-3 yr following compost application.
0
2
4
6
8
10
12
High Pcompost
Low Pcompost
Control
Ru
no
ff P
co
nc
en
tra
tio
n, p
pm
Dissolved P
Total P
01-04. Runoff P concentrations were very high 1-3 yr following compost application.0
2
4
6
8
10
12
High Pcompost
Low Pcompost
Control
Ru
no
ff P
co
nc
en
tra
tio
n, p
pm
Dissolved P
Total P
0
1
2
3
4
5
High Pcompost
Low Pcompost
Control
P lo
ss
, lb
/ac
re
Dissolved P
Total P
Runoff P loss was greater with compost applied, but not so much given the difference in soil test P.
2004-05
Soil P levels remained very high where compost had been applied 4 years before
Plowing greatly reduced P at the soil surface.
0
2
4
6
8
10
12
0 400 800 1200 1600
Total soil P, ppm
Soil
dept
h, in
ch
02468
1012
0 100 200 300 400 500
Bray-P1, ppm
Soil
dept
h, in
ch
No compost
Compost
Compost-plowed
2004-05 P loss The residual effect of
compost at 4 – 5 yr after application♦ Much more dissolved
P loss♦ About 100% more
total P loss
The effect of plowing♦ Greatly reduced
dissolved and total P loss
0
0.4
0.8
1.2
1.6
2
No compostapplied
Compostapplied
Compostapplied,plowed
P lo
ss, l
b/a
cre Dissolved P
Total P
Phase IV, 2006-2007
Continued study of residual effects
Vegetative filter strips occupying 1 or 4% of the plot area
Summary
Effects of composted manure application persisted during, and for 5 years after, application♦ Greatly increased soil test P♦ Increased runoff P concentration♦ Reduced volume of runoff and erosion♦ Increased runoff P loss
Summary
Runoff P loss was more affected by change in erosion and runoff rates compared to soil test P
Excessive amounts of P can be applied with little loss if there is little erosion and runoff.
Summary
Plowing soil with excessively high surface P reduced♦ runoff with no increase in erosion♦ P concentration in runoff, and♦ P loss.♦ However, erosion needs to be prevented.
Well-placed vegetative filter strips occupying 1% of the land area are reducing runoff and P loss
P index development
A comparison of 5 PIs from the Midwest.
Differences evaluated considering research results
J. Soil Water Conserv. Developed P index for
Nebraska together with NRCS
Site/management factors
Soil P levels P application practices:
time, rate and method of application
Management practices such as tillage, cover crops, conservation practices, etc.
Transport factors Runoff Erosion: rainfall,
snowmelt and irrigation
Distance from center of ‘field’ to a stream, water body, etc.
•Erosion > runoff >> soil test P >Erosion > runoff >> soil test P > distance to water body if within 300 ft > P application practice
Results from Nebraska P Index: scores and ratings
Erosion
rate, t/A
Soil Bray-1 P, ppm
20 100 250 500
2 0.7, L 1.2, L 2.1, M 3.7, M
Results from Nebraska P Index: scores and ratings
Erosion
rate, t/A
Soil Bray-1 P, ppm
20 100 250 500
2 0.7, L 1.2, L 2.1, M 3.7, M
8 2.4, M 3.7, M 6.0, H 10.1, H
Results from Nebraska P Index: scores and ratings
Erosion
rate, t/A
Soil Bray-1 P, ppm
20 100 250 500
2 0.7, L 1.2, L 2.1, M 3.7, M
8 2.4, M 3.7, M 6.0, H 10.1, H
16 4.7, M 7.0, H 11.3, H 18.4, VH
Erosion calculatorErosion (t/ac) = 12.5* LU * CP * ((K–
0.32)*0.5+0.32)/.32 * SF * R/135 * T * I
•LU = Land use
•CP = Conservation practice
•K = Soil erodibility
•SF = Intermediate slope factor
•R = County rainfall factor
•T = Tillage factor
•I = Irrigation
y = 1.13x + 0.38
R2 = 0.89
0
5
10
15
20
0 5 10 15 20
RUSLE2
Ero
sio
n E
sti
ma
tor
Reducing Risk of Phosphorus Pollution of Surface Waters in Crop-Ethanol-Livestock Ecosystems of the Midwest
C. Wortmann ([email protected]), C. Shapiro, D. Tarkalson, Dept. Agronomy & HorticultureH. Nourdenni, Chemical Engineering G. Erickson, Animal ScienceT. Franti, D. Schulte, Bio-systems EngineeringD. Jose, Agricultural EconomicsK. Brunkhorst, Nebr. Corn Board
USDA-CSRESS Managed Ecosystems/Nebraska Corn Board
P reduction project: feeding beef a ration of 40% bi-products results in 100% more P excretion
(and >75% more NH3 volatilization)
P removal from ethanol stream
Composting vs. stock-piling feedlot manure
Development of decision guide
Research on bulk reduction and N loss with composting
Effect of vegetative buffers on P runoff
Setback distance ….
Effect of non-application (setback) distance to concentrated water flow.
Watersheds: GIS and stakeholders Linking GIS, watershed
model, and index tools with local knowledge♦ Develop BMP targeting
criteria for producers/ advisors for pollutants
♦ GIS linked with simple tools (e.g. RUSLE1, modified P index) for use at field level with producers/stakeholders
Heartland Regional Water
Use
Our Heartland approach Focus areas
♦ 2004 P management♦ 2005: N management♦ 2006: Pesticide
management♦ 2007: Targeting the
application of BMPs in landscapes
Activities♦ Regional research
roundtable♦ Regional training
workshop♦ Develop or enhance
extension resources Extension circulars Web site On-line lessons In-state training
activities
Heartland ….
2007 Heartland NPM Workshop
Targeting the application of BMPs in landscapes
June 5-7 in Nebraska City
http://websoilsurvey.nrcs.usda.gov
http://websoilsurvey.nrcs.usda.gov