http://www.extension.org/67629 To meet Chesapeake Bay Total Maximum Daily Load requirements for agricultural pollution, conservation districts and farmers are tasked with implementing best management practices (BMPs) that reduce farm losses of nutrients and sediment. The importance of the agricultural industry to the regional economy highlights the need for determining cost-effective BMP solutions given the geographical and operational characteristics of these farms. This study evaluated both the environmental risk and farm profitability of common farm-level management practices for three major farm types in the region: crop, tractor-based ("English") dairy, and horse-drawn ("Amish") dairy.

1. Farm-System Modeling to Evaluate
Environmental Losses and Management
Practice Cost-Effectiveness
Andy McLean, Tamie Veith, Al Rotz,
Jim Hamlett, Jim Shortle
USDA-ARS Pasture Systems and Watershed
Management Research Unit & The
Pennsylvania State University

2. Loadings to the Chesapeake Bay
Agriculture dominates all
other sectors for nutrient and
sediment contributions
57%
45%
70%Legend
Agriculture
Point Source
Forest
Developed

3. Study Region
Chesapeake Bay
Susquehanna River
Dauphin County
Lebanon County
Lancaster
County

4. Most Beneficial Practices as
Determined by Regional Studies
Rank Lancaster County
Informal Study (2004)
CBC (2004) Cost-effective
strategies for the Bay
1 Nutrient management plan Wastewater Treatment Plant Upgrades
2 Cover crops Diet and Feed Adjustments
3 Management advice Traditional Nutrient Management
4 Structural field practices Enhanced Nutrient Management
5 Conservation tillage Conservation Tillage
6 Implement farm conservation
plan
Cover Crops
7 Cultural field practices (crop rotation, etc.)
8 Develop farm conservation plan
9 Grass buffers, 15-ft
10 Animal waste system

5. Objective
Simulate representative farming
systems for this region to determine
the environmental benefit of
management practices and determine
their economic value to the producer

6. Baseline Descriptions
Crop Farm
Old Order Amish
Dairy
Contemporary
Dairy
400 ha (1000 ac)
4 yr rotation
C-SB-C-SB/WW
Primarily no-till
Import poultry manure
& some starter fertilizer
100 cows
120 ha (300 ac)
8 yr rotation
2(Cg)-2(Cs/WW)-4(Hay)
Primarily no-till
Low grain to forage
50% rented fields
50 cows
24 ha (60 ac)
8 yr rotation
4(Cs/WW)-4(Alfalfa)
Conventional-till
High grain to forage
Horse-drawn methods

7. Practices Investigated
Farm Management Cropping Strategies
Nutrient Management
Treatment Strategies
Tillage (conv., mulch, no)
Strip cropping
Manure storage (4, 6, 12 month)
Manure reallocation among crops
Manure application
(broadcast, immediate incorp.) Field-edge grass buffer
Crop conversion
(50% silage to grazed pasture)
Cover Crop
(mulch winter grain)
Double Crop
(harvest winter grain)
Dietary P (100%, 120% of NRC)
Dietary N (100%, 110% of NRC)
Tests against prior methods

8. Integrated Farm System Model
(IFSM)
Soil
Establish
Crop Harvest
Storage
AnimalManure
Grazing
Volatile loss
Exported manure
Purchased feed,
bedding, etc.
Feed sold
Volatile
loss
Fixed
nutrients
Volatile loss
Purchased
fertilizer
Runoff &
Leaching loss
Milk and
animals
Engine exhaust

9. Challenges of Modeling an Amish
Dairy Farm
Machinery Differences
 Machine specifications
 Operational efficiency
 Power requirements
 Costs
 Horses vs. Tractors
Corn Harvest

10. Challenges of Modeling an Amish
Dairy Farm
Operational Differences
 Labor requirements
 Timing of operations
 Representing horses

11. BASELINE RESULTS

12. Yield Comparison (t DM/ha)
IFSM
Crop
IFSM
Cont.
Dairy
NASS
District
Cons.
Corn grain 8.7 (2.0) 7.8 (1.6) 5.9 – 7.9 8.5
Corn silage — 16 (2.3) 16 16 – 21
Soybeans 2.8 (0.3) — 2.2 – 2.7 2.9
Small grain 4.2 (0.4) 1.8 (0.2) 3.0 – 3.9 5.2
Alfalfa — 9.4 7.7 11 – 13.5

13. Operational Timing (day of year)
IFSM
Crop
IFSM Cont.
Dairy
District
Cons.
Corn plant 129 116 110
Corn harvest 284-289 247-286 283
Wheat plant 297 309 293
Wheat harvest 183-184 118-116 176-186
Soybean plant 133 130
Soybean harvest 289-294 288-298
Hay harvest 4 cuttings 3-5 cuttings

14. Amish Dairy
Labor Requirements (hour)
IFSM Total
Labor
Extension
Estimate
Corn planting 65 99
Hay harvest 71 60
Corn silage harvest 335 270
Small grain planting 55 40
Manure handling 349 360

15. Avg. Nutrient Loss (kg/ha-yr)
IFSM
Crop
IFSM
Contemp.
Dairy
IFSM
Amish
Dairy
Chesapeake
model
N volatilized 10.4 69.2 122.7
N leaching 29.7 20.8 44.8
N denitrified 16 14.5 35.3
P runoff
(sed+sol)
1.2 0.4 1.7 0.19-0.84
P buildup 8.9 -4.6 28.2
Erosion 2132 294 2381 1424-2376

16. MANAGEMENT PRACTICE
PERFORMANCE

17. -100
-50
0
50
100
150
200
250
300
PercentChange
-50
0
50
100
150
200
PercentChange
Phosphorus Runoff Sediment Runoff
Crop Farm

18. -25
-20
-15
-10
-5
0
5
10
15
20
25
PercentChange
-40
-20
0
20
40
60
80
100
120
140
PercentChange
Nitrogen Leaching Return to Management
Crop Farm

19. -50
0
50
100
150
200
250
300
350
400
PercentChange
-50
0
50
100
150
200
250
300
350
400
450
PercentChange
Phosphorus Runoff Sediment Runoff
Contemporary Dairy

20. -50
0
50
PercentChange
-10
0
10
20
PercentChange
Nitrogen Volatilization Nitrogen Leaching
Contemporary Dairy

21. -15
-10
-5
0
5
10
15
20
PercentChange
Return to Management
Contemporary Dairy

22. -100
-75
-50
-25
0
25
PercentChange
-75
-50
-25
0
25
PercentChange
Phosphorus Runoff Sediment Runoff
Amish Dairy

23. -50
-25
0
25
PercentChange
-5
0
5
10
15
20
PercentChange
Nitrogen Volatilization Nitrogen Leaching
Amish Dairy

24. -100
-75
-50
-25
0
25
PercentChange
Return to Management
Amish Dairy

25. Amish Dairy
• No-till
• Pasturing
• Strip cropping
• Cover cropping (baseline)
Contemporary Dairy
• Cover cropping
• Nutrient management
• Strip cropping
• No-till (baseline)
Crop Farm
• Cover cropping
• Double cropping
• No-till
• Strip cropping
• Grass buffer
Best environmental practices for
each farm?

26. Most profitable management
practices for each farm
Amish Dairy Farm
• Double cropping
• Mulch tillage
Contemporary Dairy
Farm
• Nutrient management
• Reduced manure storage
Crop Farm
• Cover cropping
• Double cropping
• Nutrient management
• Reduced tillage

27. Distributions Across 25 Years of Weather
Nitrogen loss
Phosphorus loss
Farm profit

28. Cost Effectiveness
Phosphorus loss Nitrogen loss

29. Conclusions
 Most management practices have a nutrient
tradeoff - at least as they are modeled in this study
 Farm operation/strategy/location may have a
significant impact on which practices are best
 Double cropping shows great potential
 Cost-effective reductions from ―low-hanging
fruit‖
 Corn appears to be water limited, not nutrient
limited, therefore we may be over-applying nutrients to
corn
 Profitability and the environment benefited from
transferring manure nutrients from corn to small grain

30. Application of Results
 Provide a basis for recommendations by
conservation district officials and policymakers
 Hopefully encourages farmers to experiment with
these practices

31. USDA
Pasture Systems and Watershed
Management Research Unit
University Park, Pennsylvania
Agricultural Research Service