The full proceedings paper is at: http://www.extension.org/72770 Throughout the Puget Sound region of Northwest Washington, impacted and poorly managed agriculture has repeatedly been advanced as a leading contributor to surface and ground water pollution. The purpose of this study was to develop and field test different manure application strategies and support real-time Application Risk Management (ARM) tools to minimize the transport of manure nutrients (N, P) and fecal coliform (FC) via runoff and leaching.

1. Implementation of a
Progressive Manure
Application Management
(ARM) System to Protect
Watersheds from Agricultural
Runoff and Leaching Events
Nichole Embertson, Ph.D.
Whatcom Conservation
District
Waste to Worth, Seattle, WA
April 2, 2015

3. Protecting Puget Sound Watersheds
from Agricultural Pollution Using a
Progressive Manure Application
Risk Management (ARM) System
 A method of assessing and
mitigating the runoff and leaching
risk associated with manure
application on a temporal (timing)
and spatial (location) scale year-
round.N. Embertson, S. Cox, C. Clark, and G.
Boggs

4. 4 R’s of Nutrient Management
4 R’s Nutrient
Management
(NRCS)
Right Time
Right Rate
Right
Source
Right
Placement

5. Application Risk Management
 You want to apply, so what should you do?
1. Determine agronomic rate
2. Identify optimal fields (field risk map)
3. Determine current conditions:
o Manure Spreading Advisory (MSA)
o Seasonal Manure Setbacks
4. Assess field and fill out ARM Worksheet
5. Apply and monitor fields
Do this assessment year round!

6. Identify Low Risk Fields
Runoff Risk Rating
(October-June)
Leaching Risk Rating
(June-October)

7. Manure
Spreading
Advisory
 Real-time
 Auto-update from
NOAA
 Runoff risk
 Soil leaching risk
layer May 2015
~100
pageviews per
month
www.whatcomcd.org/M
SA

8. Runoff Risk Ratings (Jan-May)

9. ARM
Worksheet
 Fill out
Worksheet
Forecast
Field Conditions
Protective
Measures
 Send to WCD
 Runoff Risk by
field and day
 Recordkeeping &

10. ARM Worksheet Parameters
 Precipitation 24 h
 Precipitation 72 h
 Soil type
 Soil moisture
 Water table depth
 Forage density
 Forage height
 Field surface
condition
 Manure application
equipment
 Waterbody adjacent
 Application setback
 Buffer width
 Risk Rating

11. Nutrient Management Plan
Guidance
https://sites.google.com/site/wadairypla

12. ARM Field Measurements
 Provide field data to:
Better understand nutrient cycling
Determine risk level of fields
Tune risk values/thresholds in
Worksheet
Validate MSA
 Data collection to be completed: April
2015

13. Site Characteristic
 6 paired 5 acre plots
 All plots in grass/forage production
 2 treatments:
 CON = Conventional application
timing
 ARM = Application Risk
Management
 2 Soil types:
 Silt Sandy loam (4 plots) – Deep,
well drained, low runoff, not
saturated

14. Field Testing Parameters
Surface Water: FC, NO3, NH4, P, Temp,
pH
Soil Water: NO3, NH4, TN, TP, pH
Groundwater: NO3, NH4, TN, TP, Cl
Soil: NO3, NH4, TN, TP, pH, OM, Cond,
temp, moisture
Forage: NO3, N, P, K, yield, height, density
Manure: NO3, NH4, TN, TP, pH, rate
Meteorological: Precip, temp

15. Field Evaluation Setup

16. Forage Yield
- Yield was 10-
40% greater when
early season (Jan)
application was
made (sand).
- Yield increase
was due to forage
density (25%↑),
not height.
- Silt had delayed
response in yield.
- Late fall
application on silt
lead to greater
spring yield.
0.00
0.50
1.00
1.50
2.00
2.50
Spring - Sand Spring - Silt Summer -
Sand
Summer - Silt Fall - Sand Fall Silt
Yield(ton.acre)
p<0.05
CON
ARM

17. Soil Phosphorous
0
50
100
150
200
250
300
350
400
450
500
10/6/2011
11/6/2011
12/6/2011
1/6/2012
2/6/2012
3/6/2012
4/6/2012
5/6/2012
6/6/2012
7/6/2012
8/6/2012
9/6/2012
10/6/2012
11/6/2012
12/6/2012
1/6/2013
2/6/2013
3/6/2013
4/6/2013
5/6/2013
6/6/2013
7/6/2013
8/6/2013
9/6/2013
10/6/2013
11/6/2013
12/6/2013
1/6/2014
2/6/2014
3/6/2014
4/6/2014
5/6/2014
6/6/2014
7/6/2014
8/6/2014
9/6/2014
10/6/2014
11/6/2014
12/6/2014
1/6/2015
2/6/2015
P1(Bray)(mg/kg)
CON12
CON24
CON36
ARM12
ARM24
ARM36

18. Soil Nitrate
 Nitrate trended with soil temperature (dashed
line)
 Late application (October) on sandy soil
yielded higher fall/winter nitrate levels

19. Groundwater Nitrate

20. Surface Runoff
- Surface
grab
samples
- Manure
application
setbacks
prevented
manure
runoff into
stream
- No
correlation
between FC
and NH4-N,
NO3, P, or
TN
Manure Application
Event

21. General Conclusions
 Nitrate leaching in the fall/winter is
determined by nitrogen application in the fall
(Sept-Oct)
 Irrigation can push N/nitrate in soil profile in
summer
 Runoff is a factor for rain events on limiting
(saturated) soils in spring
 Soil type has big influence on runoff and
leaching potential/magnitude
 Manure N conversion/availability varies
throughout the year and challenges 4Rs

22. ARM Outcomes
 Develop customized manure application
strategies for farms
 Optimize manure application timing by soil
type to minimize losses
 Create real-time management tools to help
make nutrient management decisions
 Number of dairies in Whatcom with full ARM
plan : 35% (~12,200 acres)

23. Questions?
Nichole M. Embertson, Ph.D.
Nutrient Management and Air Quality Specialist
Whatcom Conservation District
O: (360) 526-2381 x 126
E: NEmbertson@WhatcomCD.org
www.WhatcomCD.org
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