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![Fossil Energy Inputs [GJ ha-1 yr-1],
2008-2014
2-Year
Rotation
3-Year
Rotation
4-Year
Rotation
Fuel for Operations 2.6 2.0 1.8
Fertilizer 5.5 0.9 0.9
Herbicide 0.4 0.3 0.2
Seed Production 0.3 0.3 0.3
Grain Drying 1.5 1.0 0.8
Total Energy Costs 10.3 4.5 3.9
About 0.6 barrels of oil equivalent = about 25 gallons diesel equivalent per acre](https://image.slidesharecdn.com/liebmanswcsjuly2017-170816130613/75/Evaluation-of-Contrasting-Crop-Rotation-Systems-19-2048.jpg)
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Evaluation of Contrasting Crop Rotation Systems
This document summarizes research on crop rotations in Iowa. A 2-year corn-soybean rotation is compared to 3-year and 4-year rotations that include oats, red clover, and alfalfa. The longer rotations require more labor but use 86-96% less nitrogen fertilizer and 97% less herbicide. Soil quality improves with longer rotations, which also have similar or higher yields compared to the 2-year system. Integrating livestock through manure application provides nitrogen to the crops and improves the economics and environmental sustainability of the farming system.
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Evaluation of Contrasting Crop Rotation Systems
- 1. Sustainable agriculture “Sustainable agricultureis the production of food, fiber, and fuel using farming techniques that protect the environment, public health, human communities, and animal welfare. This form of agriculture enables us to produce a sufficient amount of healthful food now without compromising the ability of future generations to do the same.” Evaluation of Contrasting Crop Rotation Systems Using Multiple Performance Criteria Matt Liebman Iowa State University
- 2. Iowa, 2015: 2.5 billionbushels of corn harvested 554 million bushels of soybean harvested 2.2 million cattle, 46.6 million hogs & pigs, 12.5 billion eggs marketed 4.0 billion gallons of ethanol produced http://www.nass.usda.gov/Statistics_by_State/Iowa/Publications/Annual_Statistical_Bulletin/2016/ http://iowarfa.org/resource-center/statistics/
- 3. A SIMPLIFIED, HOMOGENEOUSLANDSCAPE Corn and soybean in Iowa: 63% of total land area, 82% of cropland Wright County, 2014 583 sq. miles (1,509 sq. km.) Yellow = corn Green = soybean USDA-NASS Cropland Data Layer
- 4. Hatfield et al.,2009, JSWC Alfalfa and other hay crops Small grains Large reduction in area planted to small grains, alfalfa, and other hay crops within the Raccoon River Basin from 1949 through 1997.
- 6. Challenges in Midwesternsystems related to low crop diversity and decoupled crop and livestock production • Soil erosion • Water quality degradation via nutrient and pesticide emissions • Herbicide resistant weeds • New crop diseases • Reductions of wildlife populations, including monarch butterflies, bees and other pollinators
- 7. Can cropping systemdiversification and crop-livestock integration: • reduce reliance on synthetic fertilizers, pesticides, and fossil energy? • maintain or increase crop productivity and profitability? • improve important indicators of environmental performance?
- 8. 2-year rotation: corn-soybean(cash grain) 3-year rotation: corn-soybean-oat/red clover (green manure) 4-year rotation: corn-soybean-oat/alfalfa-alfalfa (hay) 36 plots, 18 m x 84 m each, all phases of system present every year 2001 and 2002: base-line sampling / 2003-2005: start-up period 2006-present: mature period
- 9. Management practices 2-year rotation3-year and 4-year rotations Manure None 16 Mg/ha before corn Synthetic N fertilizer 112 kg N/ha at planting plus sidedress None at planting, but with sidedress option Herbicides Broadcast in corn and soybean phases Banded with interrow cultivation in corn and soybean phases Tillage Chisel plow after corn Moldboard plow after clover and alfalfa, chisel plow after corn
- 10. Mean annual mineralN fertilizer and herbicide use, 2006-2016 N fertilizer Herbicides Rotation 2-year 3-year 4-year 2-year 3-year 4-year kg N/ha kg a.i./ha Corn 170 33 27 1.33 0.07 0.07 Soybean 2 2 2 1.63 0.12 0.12 Oat -- 2 2 -- 0 0 Alfalfa -- -- 2 -- -- 0 Rotation av. 86 12 8 1.48 0.06 0.05 Reduction -86% -91% -96% -97%
- 11. Mean yields, 2006-2016 Sources:Liebman et al. 2008; Davis et al. 2012; Hunt et al. 2017 Yield, Mg/ha Rotation Corn Soybean Oat Alfalfa 2-year 12.0 b 3.16 c --- --- 3-year 12.4 a 3.56 b 3.33 b --- 4-year 12.6 a 3.76 a 3.51 a 9.18
- 12. Mean weed biomassin 2006-2016 was low in the corn and soybean phases of each system. Weed growth was greater in oat and alfalfa phases. Within columns, means followed by different letters are significantly different. Weed biomass, kg/ha Rotation Corn Soybean Oat Alfalfa 2-year 2 b 3 b --- --- 3-year 15 a 20 a 76 a --- 4-year 9 ab 8 b 72 a 58
- 13. Rotation effects onsoybean in 2010 during SDS epidemic: Longer rotations were healthier 3-year rotation 2-year rotation Measurements by L. Leandro, ISU Plant Pathology & Microbiology Photo courtesy of L. Miller
- 14. Longer rotations: lower SDSincidence, reduced SDS severity, higher soybean yield. Leandro et al. (in press)
- 15. SOIL HEALTH Large reductionin abundance of Fusarium virguliforme DNA per gram of soil in longer rotations Leandro et al. (in review) C: corn S: soybean 2: 2-yr rotation 4: 4-yr rotation Note log scale
- 16. Soil Quality Indicatorsin Corn (0-20 cm) Rotation Particulate organic matter carbon Microbial biomass carbon Potentially mineralizable nitrogen mg POM-C cm-3 soil μg C g-1 soil mg PMN cm-3 soil 2-year 1.90 b 312.6 b 31.2 b 3-year 2.31 a 388.7 ab 40.4 a 4-year 2.19 a 472.2 a 37.3 ab Sources: Lazicki et al., 2016; King and Hofmockel, 2017 Soil managed with longer rotations had more POM-C, greater microbial biomass, and higher PMN.
- 17. Tomer & Liebman(2014) Mean NO3-N concentrations in water samples collected under each cropping system, 2004-2011
- 18. Estimated Sheet andRill Erosion (RUSLE2) Mg per hectare per year 2-year rotation: 2.64 3-year rotation: 2.25 (-15%) 4-year rotation: 1.75 (-34%)
- 19. Fossil Energy Inputs[GJ ha-1 yr-1], 2008-2014 2-Year Rotation 3-Year Rotation 4-Year Rotation Fuel for Operations 2.6 2.0 1.8 Fertilizer 5.5 0.9 0.9 Herbicide 0.4 0.3 0.2 Seed Production 0.3 0.3 0.3 Grain Drying 1.5 1.0 0.8 Total Energy Costs 10.3 4.5 3.9 About 0.6 barrels of oil equivalent = about 25 gallons diesel equivalent per acre
- 20. Hunt et al.2017 Freshwater ecotoxicological potential of herbicides, 2008-2016, USEtox model
- 21. Input costs weretaken from ISU Extension’s annual report “Costs of Crop Production in Iowa,” and from local businesses. Machinery operation and labor costs were based on field notes and ISU’s “Estimating field capacity of farm machines.” Grain and hay prices were taken from marketing year averages provided by the Iowa office of the USDA National Agricultural Statistics Services. Subsidy payments and insurance pay-outs were not included in revenue figures. Manure was assumed to be generated by on-farm or near-by livestock and without cost for the material, but with labor and machinery costs for spreading. Analyses were conducted for 2008-2016 data. Economic Analyses Cost and Price Assumptions
- 22. Labor and economics,2008-2016 Rotation 2-year 3-year 4-year Labor inputs (hr/ha) 1.7 c 3.0 b 3.5 a Gross returns ($/ha) 1699 a 1507 b 1576 b Costs of production (with labor, but not land, $/ha) 872 a 625 c 684 b Profits (returns to land and management, $/ha) 827 a 882 a 892 a Diversity greater labor requirements, lower gross returns, lower costs, similar profits Hunt et al. 2017 and unpublished data
- 23. The cost ofmanure • Our primary analyses assumed that there were labor and machinery costs for spreading manure, but that there was no cost for the material itself. • How much could a crop farmer using the 3-year or 4-year rotations pay for manure and still match the profitability of the 2-year rotation, which didn’t receive manure? • 3-year rotation: $8.55/Mg (fresh weight) • 4-year rotation: $13.48/Mg (fresh weight)
- 24. Increasing cropping systemdiversity and reintegrating crop and livestock production can balance productivity, profitability, and environmental health Hunt et al. 2017. Env. Sci. & Tech., doi:10.1021/acs.est.6b04086 Davis et al. 2012. PLoS ONE, doi:10.1371/journal.pone.0047149
- 25. Special thanks to: •C. Chase • A. Davis • M. Fiscus • J. Hill • N. Hunt • D. James • A. Johanns • A. King • P. Lazicki • L. Leandro • D. Sundberg • M. Tomer • M. Wander • M. Woods
- 27. 2011 Wright County,Iowa 0 1.42 2.84 4.26 miles LandOCoverOCategories DbyOdecreasingOacreage-O AGRICULTURE Corn Soybeans GrasslandOHerbaceous Alfalfa OtherOHay/NonOAlfalfa Oats WinterOWheat SweetOCorn Sod/GrassOSeed Fallow/IdleOCropland DblOCropOWinWht/Soybeans Rye Clover/Wildflowers Switchgrass NON-AGRICULTURE* Developed/OpenOSpace WoodyOWetlands DeciduousOForest Developed/LowOIntensity HerbaceousOWetlands OpenOWater Produced by CropScape - http://nassgeodata.gmu.edu/CropScape * Only top 6 non-agriculturecategroies are listed. A SIMPLIFIED, HOMOGENEOUS LANDSCAPE Corn and soybean in Iowa: 63% of total land area, 82% of cropland Wright County, 2011 583 sq. miles (1,509 sq. km.) Yellow = corn Green = soybean USDA-NASS Cropland Data Layer
- 28. How are agriculturalsystems affected by low crop diversity and decoupled crop and livestock production?
- 30. Yield reduction formajor crops grown in shortened rotations or monoculture Crop Yield decline Barley (Hordeum vulgare) 11-19% Corn (Zea mays) 7-36% Oilseed rape (Brassica napus) 3-25% Potato (Solanum tuberosum) 10-30% Rice (aerobic) (Oryza sativa) 19-54% Soybean (Glycine max) 8-20% Sugarcane (Saccharum spp.) 3-50% Sweet potato (Ipomoea batatas) 21-57% Wheat (Triticum aestivum) 9-20% Bennett et al. (2012) Biological Reviews 87: 52-71
- 31. Why do reductionsin crop diversity lead to lower yields? (1) Build-up of plant pathogens, nematodes, insect pests, & weeds (2) “Deleterious rhizosphere microorganisms” (3) Autotoxicity (allelopathy) (4) Degradation of soil physical and chemical properties Bennett et al. (2012) Biological Reviews 87: 52-71
- 32. Source: Janssen (1984),Plant & Soil 76:297-304, as cited in Magdoff & Weil (2004) Effects of 25 years of cropping practices and fertilizer and manure applications on soil properties MinN: mineral N fertilizer; GM: green manure; AnMan: animal manure and pasture ley Soil property Management/amendments MinN MinN + GM MinN + GM + AnMan BD (g cm3) 1.50 1.45 1.35 Total SOM (Mg/ha) 78.4 81.9 86.9 Young SOM (Mg/ha) 6.2 11.0 15.2 Old SOM (Mg/ha) 72.2 70.9 71.7 Total N (Mg/ha) 4.0 4.4 4.6 Mineralized N from young SOM (Mg/ha) 34 74 108 Mineralized N from old SOM (Mg/ha) 26 26 26
- 33. Diversification includes theintegration of crops and livestock: Composted manure is applied to red clover and alfalfa, before corn, in the 3-year and 4-year rotations. N added by clover and alfalfa through biological nitrogen fixation N, P, K, and other nutrients recycled through manure application
- 34. Managing weeds inlonger rotations with diverse tactics Asynchronous harvests Banded Stubble clipping & hay removal CultivationBand spraying
- 35. Nitrogen Fertility Management inContrasting Rotation Systems Rotation Corn 2-year 112 kg N/ha applied at planting with additional N side-dressed according to soil test results 3-year and 4-year (Legume residues + manure) No fertilizer N applied at planting N side-dressed according to test results
- 36. Tillage: In the 3-yearand 4-year rotations, red clover and alfalfa are incorporated with a moldboard plow in the fall preceding corn production. Moldboard plowing is not used in the 2-year rotation.
- 37.
- 38. Management practices foroat • Soybean residue disked or field cultivated. • Ground is then cultipacked. • Oat (IN09201) sown with JD 1520 drill @ 80 lbs/acre with red clover @ 12 lbs/acre or alfalfa @ 15 lbs/acre. • Row spacing: 7.5”. • Average oat density: 22 plants per square foot. • Direct harvest of grain with a JD 9450 combine. • Straw raked, baled, and removed. • Grain stubble mowed 5 to 6 weeks later for weed control. • September alfalfa hay harvest possible when moisture is sufficient.
- 39. Mean oat yield,2006-2016 Rotation system Yield, bu/acre @ 14% moisture 3-year, oat with red clover 93 ± 3.2 4-year, oat with alfalfa 98 ± 3.3 p = 0.0011 Average test weight: 35 lb/bu Range: 33 to 38 lb/bu
- 40. Red clover growingin oat stubble
- 41. Sustainable agriculture “Sustainable agricultureis the production of food, fiber, and fuel using farming techniques that protect the environment, public health, human communities, and animal welfare. This form of agriculture enables us to produce a sufficient amount of healthful food now without compromising the ability of future generations to do the same.” Seeding-year red clover
- 42. Second-year alfalfa yield 4.1± 0.14 tons/acre, mean ± SE
- 43. Average Nitrogen Contentof Legumes in October, 2006-2013 Shoots Roots (to 12”) Total lb N/acre Red clover (1st year) 112 43 155 Alfalfa (2nd year) 47 74 121 Average N content of composted manure applied at 7 tons/acre: 101 lbs N/acre
- 44. Mean annual mineralN fertilizer and herbicide use, 2006-2016 N fertilizer Herbicides Rotation 2-year 3-year 4-year 2-year 3-year 4-year lb N/acre lb a.i./acre Corn 152 29 24 1.18 0.06 0.06 Soybean 2 2 2 1.45 0.10 0.10 Oat -- 2 2 -- 0 0 Alfalfa -- -- 2 -- -- 0 Rotation av. 77 11 7 1.32 0.05 0.04 Reduction -86% -91% -96% -97%
- 45. Mean yields, 2006-2016 Crop2-year 3-year 4-year Corn (bu/acre) 192 b 198 a 201 a Soybean (bu/acre) 47 c 53 b 56 a Oat (bu/acre) --- 93 b 98 a Alfalfa (tons/acre) --- --- 4.1 Sources: Liebman et al. 2008; Davis et al. 2012; Hunt et al. 2017
- 46. Mean weed biomassin 2006-2016 was low in the corn and soybean phases of each system. Weed growth was greater in oat and alfalfa phases. Crop phase 2-year: Corn-Soybean 3-year: Corn-Soybean- Oat/Red Clover 4-year: Corn-Soybean- Oat/Alfalfa- Alfalfa lb/acre Corn 2 b 13 a 8 ab Soybean 3 b 18 a 7 b Oat/legume --- 68 a 64 a Alfalfa --- --- 52 Within rows, means followed by different letters are significantly different.
- 47. SDS incidence SDSseverity Large reduction in soybean sudden death syndrome in longer rotations Leandro et al. (in press)
- 48. Estimated Sheet andRill Erosion (RUSLE2) Tons per acre per year 2-year rotation: 1.18 3-year rotation: 1.00 (-15%) 4-year rotation: 0.78 (-34%)
- 49. Labor and economics,2008-2016 Rotation 2-year 3-year 4-year Labor inputs (hr/acre) 0.7 c 1.2 b 1.4 a Gross returns ($/acre) 688 a 610 b 638 b Costs of production (with labor, but not land, $/acre) 353 a 253 c 277 b Profits (returns to land and management, $/acre) 335 a 357 a 361 a Diversity greater labor requirements, lower gross returns, lower costs, similar profits Hunt et al. 2017 and unpublished data
- 50. Crop 2-year 3-year4-year Corn (bu/acre) 192 b 198 a 201 a Soybean (bu/acre) 47 c 53 b 56 a Oat (bu/acre) --- 93 b 98 a Alfalfa (tons/acre) --- --- 4.1 Mean Yields, 2006-2016 Sources: Liebman et al. 2008; Davis et al. 2012; Hunt et al. 2017.
- 51. Mean annual mineralN fertilizer use, 2006-2016 Rotation 2-year 3-year 4-year lb N/acre Corn 152 29 24 Soybean 2 2 2 Oat -- 2 2 Alfalfa -- -- 2 Rotation average 77 11 7 Reduction -86% -91%
- 53. Diversified rotations hadhigher corn yields
- 54. 2-yr vs. 3-yrand 4-yr: p=0.0069; average increase of 4% 3-yr vs. 4-yr: p=0.6871 191 198 199 Hunt et al. (2017)
- 55. • Caused bya soilborne fungus - Fusarium virguliforme • Root infection causes root rot and poor root vigor • Leaf symptoms caused by fungal toxins moved from roots to leaves • Disease favored by cool, wet weather • Yield losses can be severe Sudden Death Syndrome
- 56. Diversified rotations hadhigher soybean yields
- 57. 2-yr vs. 3-yrand 4-yr: p<0.0001; average increase of 19% 3-yr vs. 4-yr: p=0.1408 47 55 57 Hunt et al. (2017)
- 58.
- 59. Estimated Sheet andRill Erosion (RUSLE2) Tons per acre per year 2-year rotation: 1.18 3-year rotation: 0.92 (-22%) 4-year rotation: 0.71 (-40%)
- 60. Hunt et al.(2017) Freshwater ecotoxicological potential of herbicides, 2008-2016, USEtox model
- 61. Input costs weretaken from ISU Extension’s annual report “Costs of Crop Production in Iowa,” and from local businesses. Machinery operation and labor costs were based on field notes and ISU’s “Estimating field capacity of farm machines.” Grain and hay prices were taken from marketing year averages provided by the Iowa office of the USDA National Agricultural Statistics Services. Subsidy payments and insurance pay-outs were not included in revenue figures. Manure was assumed to be generated by on-farm or near-by livestock and without cost for the material, but with labor and machinery costs for spreading. Analyses were conducted for 2008-2016 data. Economic Analyses Cost and Price Assumptions
- 62. Economic performance, 2008-2016 Rotationsystem 2-year 3-year 4-year Gross returns ($/acre) 688 a 618 b 642 ab Costs of production (including labor, but not land, $/acre) 353 a 269 b 289 b Profits (returns to land and management, $/acre) 335 a 349 a 353 a Diversity lower gross returns, lower costs, similar profits Hunt et al. (2017) and A. Johanns, unpublished data