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Farm System Modeling to Evaluate Environmental Losses, Profitability, and BMP Cost-Effectiveness
This document discusses farm-system modeling to evaluate nutrient and sediment contributions to the Chesapeake Bay from agriculture, highlighting effective management practices. It ranks strategies based on cost-effectiveness, identifying practices like nutrient management plans and cover crops as beneficial to both the environment and producers. The study concludes that management practices have nutrient tradeoffs and emphasizes the potential of double cropping and effective manure nutrient application.
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Farm System Modeling to Evaluate Environmental Losses, Profitability, and BMP Cost-Effectiveness
- 1. Farm-System Modeling toEvaluate 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 theChesapeake 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 SusquehannaRiver Dauphin County Lebanon County Lancaster County
- 4. Most Beneficial Practicesas 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 systemsfor this region to determine the environmental benefit of management practices and determine their economic value to the producer
- 6. Baseline Descriptions Crop Farm OldOrder 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 ManagementCropping 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 SystemModel (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 Modelingan Amish Dairy Farm Machinery Differences Machine specifications Operational efficiency Power requirements Costs Horses vs. Tractors Corn Harvest
- 10. Challenges of Modelingan Amish Dairy Farm Operational Differences Labor requirements Timing of operations Representing horses
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- 12. Yield Comparison (tDM/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 (dayof 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
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- 20. -50 0 50 PercentChange -10 0 10 20 PercentChange Nitrogen Volatilization NitrogenLeaching Contemporary Dairy
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- 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 practicesfor 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 25Years of Weather Nitrogen loss Phosphorus loss Farm profit
- 28. Cost Effectiveness Phosphorus lossNitrogen loss
- 29. Conclusions Most managementpractices 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 andWatershed Management Research Unit University Park, Pennsylvania Agricultural Research Service
Editor's Notes
- #2 Mike Hubler and Larry Baum from the Dauphin County Conservation District and officials at the Lancaster and Lebanon County Conservation Districts helped categorize and characterize farms.
- #3 Source of PA nutrient loadings, as calculated by the Chesapeake Bay Model
- #4 Study region is 3 counties on East side of Susquehanna River. Loadings drain to river and straight down into Bay.~2500 farmsThe larger farms are feed crop farms (corn/soybean). Average farm size = 40 ha But median = 20 haThe green (good) N area is mountain top forest.
- #6 Need to properly characterize current and suggested management impacts at the FARM level.If practice changes aren’t economically feasible, or practical with available labor, then they aren’t going to be implemented well and the anticipated pollution reduction will be overstated.
- #7 Define and characterize categories of farms for Dauphin, Lancaster, and Lebanon Counties of Southeastern PA, so that farms typical of theregion may be represented in IFSM.Simulate current farm conditions as baseline models
- #8 Apply BMP scenarios to the baseline farm models to evaluate BMP impact on nutrient/sediment losses and farm profitability.4 categories of BMPs investigated, based (roughly) on EPA’s “core four” BMP list. (i.e., the types that EPA has identified as necessary to meet goals)
- #9 Process-based, farm-scale Outputs are annualaverages over 25 years varying weather Simulates the economics of farm operations- costs, revenues, profit (return)Simulates flow of nutrients in and out of farm boundaries
- #13 Yields compared well with NASS and local conservation officialsTable 1. Yield comparison (tDM ha-1) based on USDA-NASS (2012) reports, conservation district estimates, and IFSM simulations*. * USDA-NASS (2012): 10-yr averages; Conservation District (personal communication): estimates of recent past; IFSM 25-yr mean (SD).# USDA-NASS = hay; IFSM = 2 cuts hay, 2 cuts silage.
- #14 Also evaluated operational performance of farms (timing of operations, labor requirements)
- #15 And
- #18 Graphs show percentage change from baseline for select scenariosHighlighted scenarios seemed to be the most cost-effective overall for each farm typeCC = Corn (200 ha) and soybeans (200 ha) are only cash crops. A cover crop of winter rye is grown on 100% of the corn land (200 ha) after corn harvest and killed in the spring before soybean planting.100% CC = (100% soybean land has a winter rye cover crop. 100% of corn land is cover cropped with grass. Cover crops are killed in the spring.)
- #28 Nitrogen:Contemporary Dairy seems to be more consistent but less precise (wider ranges, all centered around roughly the same median) than the crop farm. BUT the crop farm y-axis has a 20t range and the dairy y-axis range is only 10t
- #33 Distribution and density of agricultural land, elevation, and physiographic regions within a representative subregion of the study area (PennDOT 2012, USDA 2002).
- #36 A variety of sources were used to gather data and to evaluate model output, to make sure that we were accurately representing these specific farm types in southeastern PA.
- #37 Output parameters evaluated for determining the impact of the change in management practice
- #41 SPARROW estimated loadings from agricultural sources delivered to streams and rivers in the Bay watershed (1997 conditions)Total N: red category = 6 to 33 kg/ha/yrP: red = 0.2 to 0.85 kg/ha/yrSed: red = 30 to 238 Mg/km = 3,000 to 23,800 t/ha (or 300 to 2,380 kg/ha)http://stat.chesapeakebay.net/?q=node/130&quicktabs_10=1&quicktabs_15=1