Cover Crops For Midwest Farming Systems Jeremy Singer Research Agronomist
Outline Discuss cover crop effects on water quality. Review current crop demographics. Discuss options for managing agricultural landscapes.
Nitrate Trends Nitrate-N Concentration (mg/l) 12 10 8 6 4 2 Raccoon River Basin 0 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year Hatfield et al., unpublished
Nitrate Loads N Load (Mg) 25000 20000 15000 10000 5000 Raccoon River Basin DOY 1-90 DOY 91-180 DOY 181-270 DOY 271-366 0 1970 1975 1980 1985 1990 1995 2000 2005 Year Hatfield et al., unpublished
Fertilizer Application 340000 320000 Raccoon River Basin N Fertilizer Applied (Mg) 300000 280000 260000 240000 220000 200000 180000 160000 140000 1975 1980 1985 1990 1995 2000 2005 Year Hatfield et al., unpublished
Change in Animal Production 3000000 Raccoon River Livestock Production 2500000 Livestock Numbers 2000000 1500000 1000000 500000 Cattle Hogs 0 1960 1970 1980 1990 2000 2010 Year National Agricultural Statistics Service
Change in Land Use 1000000 Raccoon River Basin 800000 Area (ha) 600000 400000 200000 Small Grain Alfalfa & Hay Crops 0 1940 1950 1960 1970 1980 1990 2000 Year National Agricultural Statistics Service
Observations Nitrate losses are a small part of total N applied. Nitrate losses per acre are small but sufficient to cause high nitrate concentrations. Change in small grain and hay area is the most significant factor (r=-0.76).
Implications Develop integrated solutions that include land use changes across the watershed. Reintroduce small grain and hay acres into the watershed to change the water use and nitrate patterns.
140 Precipitation Drainage Approximate ET for corn 120 Water budget (mm) 100 80 60 40 20 0 January February March April May June July August September October November December Monthly distribution of precipitation, drainage, and approximate evapotranspiration for fifteen years at the project site (Helmers et al. 2005, ASAE)
Rotation and Nitrogen Crop system Nitrate-N lost, 4-yr total kg ha -1 Continuous corn 217 Corn-soybean 204 Soybean-corn 202 Alfalfa 7 CRP 4 Randall et al. (1997) J. Environ. Qual.
Cover Crops Cover crops are planted to provide soil cover, which can then function to: reduce soil erosion, increase water infiltration, decrease water runoff, conserve soil water, increase soil organic matter, reduce soil compaction, reduce nitrate leaching, supply nitrogen to subsequent crops, suppress weeds, attract beneficial insects, and other functions.
Table 1. Literature summary of percent reduction in N leaching losses due to rye or ryegrass winter cover crops. Adapted in part from Meisinger et al., 1991. Reference Location Cover Crop % Reduction in N leaching Morgan et al., 1942 Connecticut, U.S. Rye 66 Karraker et al., 1950 Kentucky, U.S. Rye 74 Nielsen & Jensen, 1985 Denmark Ryegrass 62 Martinez & Guirard, 1990 France Ryegrass 63 Staver & Brinsfield, 1990 Maryland, U.S. Rye 77 McCracken et al., 1994 Kentucky, U.S. Rye 94 Wyland et al., 1996 California, U.S. Rye 65-70 Brandi-Dohrn et al., 1997 Oregon, U.S. Rye 32-42 Ritter et al., 1998 Delaware, U.S. Rye 30 Kladivko et al., 2004 Indiana, U.S. Winter wheat 61 + less fert. Jaynes et al., 2004 Iowa, U.S. Rye 62 Strock et al., 2004 Minnesota, U.S. Rye 13
Table 2. Literature summary of percent reduction in total P losses in runoff due to barley, winter wheat, or legume winter cover crops. Adapted from Sharpley et al., 1991. Reference Location Cover Crop % Reduction in Total P Losses in Runoff Angle et al., 1984 Maryland, U.S. Barley 92 Langdale et al., 1985 Georgia, U.S. Rye 66 Pesant et al., 1987 Quebec, Canada Alfalfa/timothy 94 Yoo et al., 1988 Alabama, U.S. Wheat 54
Erosion Example Rill Erosion Rates in April Following No-Tillage Soybean g m -2 s -1 3 2.5 2 1.5 1 0.5 0 Rye Oat Control 1997 1998 Kaspar et al., 2001, J. Soil Water Conserv.
Cumulative annual nitrate-n load of drainage water for 2002-2005 Annual nitrate-n load (kg/ha) 90 80 70 60 50 40 30 20 10 40.4 81.1 33.9 Control Rye Cover Crop 47.2 23.0 34.4 11.2 11.1 50.8 19.8 0 2002 2003 2004 2005 Avg. Kaspar et al., In Press
Annual nitrate-n concentration (mg/l) 30 25 20 15 10 5 Average annual flow-weighted nitrate-n concentration of drainage water for 2002-2005 19.1 5.8 24.7 11.8 Control Rye Cover Crop 19.8 9.3 21.6 21.3 8.0 8.7 0 2002 2003 2004 2005 Avg. Kaspar et al., In Press
Total Nitrate-Nitrogen Lost 2002-2005 Treatment Nitrate-N lost, 4-yr total kg ha -1 Corn-Soyb w. Rye 79 Corn-soybean 201 Kaspar et al. (in revision) J. Environ. Qual.
Soybean Yield Following a Rye Cover Crop Soybean Yield (bu/ac) 75.0 70.0 65.0 60.0 55.0 50.0 45.0 40.0 35.0 Boyd 2006 Boyd 2005 Boyd 2004 Boyd 2003 Boyd 2002 Kelly 2005 Kelly 2003 AERC 2006 AERC 2005 AERC 2004 Rye CC Check AERC Avg 2003 Kaspar et al., unpublished
Corn Yield Following a Rye Cover Crop 230.0 226 Rye CC Check 220.0 217 214 210.0 209 210 209 208 Corn Yield (bu/ac) 200.0 190.0 195 193 198 189 192 194 202 189 192 200 185 185 185 184 182 180.0 177 176 176 173 170.0 Boyd 2006 Boyd 2005 Boyd 2004 Boyd 2003 Kelly 2006 Kelly 2004 Kelly 2002 AERC 2006 AERC 2005 AERC 2004 AERC 2003 AERC 2002 Avg Kaspar et al., unpublished
Corn Yield Generally, corn yield is not lowered following small grain cover crops if planting is delayed about 10 to 14 days after cover crop termination. A successful approach balances cover crop growth and timely corn planting for greater cover crop biomass.
Cover Crop Survey Results 3500 producers in IL, IN, IA, and MN. 36% response rate. 18% had ever used cover crops. 11% used cover crops within past 5 years. 8% planted cover crops on their farm in the fall of 2005 (only on 6% of land). Greater use in IL and IN. 80% using conservation practices. 43% using conservation practices with cost sharing, 57% w/out. Singer et al., In Review
Survey Results Con t Respondents replied minimum payment $23/acre to plant cover crops. 56% said they would use cover crops with cost-sharing. Additional research could target cover crop placement. Singer et al., In Review
The Challenge To develop systems that protect the soil, capture nutrients, and provide other ecosystem services in a narrow fall establishment window To increase adoption through costsharing, cash value, or other short-term added value benefits
Soybean Yield 70 60 50 23% 15% 55 46 45 52 60 65 bu/acre 40 30 2004 2005 20 10 0 4-row 2-row Check Singer et al., 2007 Agron J
Living Mulches Reasonably large body of scientific papers published on living mulches (LM). Most LM systems are corn-based.
Table 1. Living mulch (LM) species used in agronomic crop production. Crop LM Species Corn grain and silage Alfalfa, Italian ryegrass, kura clover, white clover/mixed grasses, subterranean clover, tall fescue, Kentucky bluegrass, orchardgrass, smooth bromegrass, crimson clover, birdsfoot trefoil, crownvetch, chewings fescue, ladino white clover (14) Soybean Tall fescue, subterranean clover, winter rye (3) Winter wheat White lupin, white clover, kura clover (3) Forage sorghum Alfalfa, reed canarygrass (2)
Corn Yield 250 9% 215 229 220 200 190 33% 196 182 bu/acre 150 100 153 138 46% 119 127 81 2004 2005 2006 67 50 0 Kura Alfalfa K-A-ORCH Check Singer, unpublished
Soybean Yield 80 70 64 69 60 50 25% 28% 48 50 50 59 bu/acre 40 42 40 56% 37 2004 2005 2006 30 26 20 17 10 10 0 Kura Alfalfa K-A-ORCH Check Singer, unpublished
Rainfall 9 8 8.18 7 6.76 6.16 Inches 6 5 4 4.38 3.59 4.87 4.1 5.56 5.19 2004 2005 2006 3 2 2.15 1.96 1 0.81 0 May June July August
2005 Forage Yield 6 5 4 tons DM/acre 3 2 1 0 Kura Alfalfa K-A-Orch ND alfalfa Singer, unpublished
Drainage Water Quality at Gilmore City Drainage Research Facility Impact of kura clover on nitratenitrogen concentration in subsurface drainage water Kura clover planted in spring 2005 Corn will be planted in these plots in 2007 N application rate to be determined likely 75 lbs-n/acre Compare nitrate-nitrogen concentration to pasture treatment and corn/soybean conventional treatments Treatment Corn/soybean 75 (C/S 75) Corn/soybean 125 (C/S 125) Kura clover Pasture/forage N-Application Rate to Corn (lbs- N/acre) Spring application 75 125 No fertilizer No fertilizer Source: M. Helmers - unpublished
Preliminary Drainage Water Quality Data Nitrate-nitrogen concentration (ppm) 20 18 16 14 12 10 8 6 4 2 0 C/S 75 C/S 125 Kura Clover 2005 2006 Pasture/Forage In 2006, statistically significant difference in N-concentration between C/S treatments (at both rates) and the kura and pasture treatments. Source: M. Helmers - unpublished
Questions? singer@nstl.gov 515-294-5502