Crop Rotation or Continuous Corn? Agronomic Considerations Joe Lauer University of Wisconsin-Madison Wisconsin Fertilizer, Aglime & Pest Management Conference Madison, WI January 16, 2008 1
Crop rotation plan for Monticello Thomas Jefferson, like other enlightened farmers, took a scientific approach to farming with the help of his son-in- law, Thomas Mann Randolph (1768-1828), who managed much of Jefferson's land after marrying Martha "Patsy" Jefferson in 1790. Jefferson's s careful consideration of a workable method of crop rotation for Monticello -- an innovative practice at the time -- demonstrates his interest in scientific farming.
Continuous corn? Or rotate in 2008? Wisconsin Corn Acreage Source: USDA-NASS Crop Acres Total Acres 5000 Corn For Grain Corn For Silage Soybeans Forage Alfalfa 12000 4500 Hay Other Oats Wheat All Total 4000 10000 3500 3000 2500 2000 1500 1000 500 8000 6000 4000 2000 0 1970 1975 1980 1985 1990 1995 2000 2005 2010 0 3
Million Bushels 500 400 300 200 100 0-100 Continuous corn, or rotate in 2008? Wisconsin Corn Use Sources: USDA-NASS NCGA: The World of Corn 450 437 429 400 425 403 404 408 348 392 363 368 354 91 333 121 105 330 137 164 206 194 216 203 175 180 142 152 72 110 149 165 70 175 190 202 199 225 190 196 193 190 207 204 199 202 204 198 190 145 116 56 73 27 27 0 0 0 2 2 2 2 2 2-35 -82-37 -51-73 -96-94 -99-81 -62-64 -91-81 -82-85 -108 Ending stocks Residual/Exports Feed Ethanol Corn production 4
Overview The Rotation Effect What is it? Interactions to watch out for 5
Crop Rotation The Rotation Effect What is it? Universal management practice Proven management decision that increases crop yields Currently, increased economic benefit for monoculture Rotation Effect The effect of all conditions, other than N, supplied by legumes in a rotation (Baldock et al. 1981) Other non-legume crops can provide benefits as well (Robinson, 1966; Langer and Randall, 1981; Crookston et al., 1988) Additional benefits of rotating crops All production inputs can be optimized Typical problems associated with monoculture are not apparent. Mechanism for effect is unknown
The rotation effect lasts two years increasing corn grain yield 10 to 19% for 1C and 0 to 7% for 2C 200 Corn Yield Response Following Five Years of Soybean 1987-2006 /acre) 180 178 179 Control treatments averaged across tillage treatments at Arlington, WI. Grain Yield (bushels/ 160 140 162 155 156 155 151 120 18% 19% 7% 3% 3% 3% A A B CD C CD D 100 Source: Lauer CS 1C 2C 3C 4C 5C Cont. Cropping Sequence C= Corn, S= Soybean, Number = consecutive year of corn
The rotation effect lasts two years increasing soybean grain yield 10 to 20% for 1S and 8% for 2C Grain Yield (bushels/ /acre) 70 60 50 40 30 20 54 Soybean Yield Response Following Five Years of Corn 59 53 50 50 10% 20% 8% 2% 1% -1% 1987-2006 Control treatments averaged across tillage treatments at Arlington, WI. 48 49 10 B A B C CD D CD 0 Source: Lauer CS 1S 2S 3S 4S 5S Cont. Cropping Sequence C= Corn, S= Soybean, Number = consecutive year of soybean
A one year break using soybean reduces the rotation effect in the second phase (NS to CC) Grain Yi ield (bushe els/acre) 220 200 180 160 140 120 Corn Yield Response to Crop Rotation 1998 to 2000 215 218 214 200 192 Control treatments averaged across tillage treatments at Arlington, WI. 201 192 12 % 14% 4% 0% 11% 5% A A B B A B B 100 Source: Lauer Cropping Sequence C= Corn, S= Soybean, Number = consecutive year of corn
At least two break years are needed to measure a response in the second crop phase Corn Yield Response to Crop Rotation Grain Yi ield (bushe els/acre) 180 173 170 169 164 161 160 160 156 157 153 140 10 16 12 7 5 18 8 16 10 120 % % % % % % % % % 1990-2004 Control treatments at Lancaster, WI. 146 CD AB BC D DE A CD AB CD E 100 Source: Stanger and Lauer, 2008 Cropping Sequence A= Alfalfa, C= Corn, O= Oat, S= Soybean, W=Wheat
Adding a third crop does not increase corn grain yield, but does improve soybean grain yield 220 Corn and Soybean Yield Response to Crop Rotation Corn 70 Corn Grain Yield (bushels/ /acre) 200 180 160 140 120 200 Soybean 192 192 56 59 57 60 173 46 50 40 30 16% 11% 11% 22% 28% 24% A A A B B B AB C 20 Soybean Grain Yield (bushels/ /acre) 100 Source: Lauer CS CSW CWS CC CS CSW CWS SS Cropping Sequence C= Corn, S= Soybean, W=Wheat 10 2004-2006: Values averaged across seed fungicide treatments at Arlington, WI.
Management Decision Interactions with Rotation Significant Tillage N rate CR Insecticide CR Variant = NS (need all the time) Environment Non-significant Plant density Row spacing Modern hybrids versus old hybrids Modern hybrids can handle continuous corn
Modern corn hybrids and management practices have the same rotation response as older hybrids and practices Corn Yield Response Following Five Years of Soybean Grain Yiel ld (bushels s/acre) 220 200 180 160 140 120 159 160 Cycle 1: 1987-1996 1996 Cycle 2: 1997-2006 210 213 Control treatments averaged across tillage treatments at Arlington, WI. Transgenic hybrids used since 1998. 191 145 138 139 138 19 19 8 3 4 3 % % % % % % 134 183 185 185 16 18 6 1 2 2 % % % % % % A A B CD C CD D A A B C BC C C 181 100 Source: Lauer CS 1C 2C 3C 4C 5C Cont. CS 1C 2C 3C 4C 5C Cont. Cropping Sequence C= Corn, S= Soybean, Number = consecutive year of corn
Tillage does not affect corn yield the first year following soybean, but improves yield 5% in the second year, and 9% in the third year No tillage response is observed in the second cycle Corn Yield Response Following Five Years of Soybean d (bushels s/acre) Grain Yiel 200 180 160 140 177 180 178 179 166 158 162 163 163 148 150 147 Conventional tillage No tillage Control treatments during 1987-2006 at Arlington, WI. 160 143 152 139 194 194 120-1% 1% 5% 9% 9% 9% 12% 9% 0% A A A A B C BCDE BC D BCDE C E A B C C 100 Source: Lauer CS 1C 2C 3C 4C 5C CC 1987-1997- Cropping Sequence 1996 2006 C= Corn, S= Soybean, Number = consecutive year of corn
N fertilization response increases in 2C and 3C of the rotation, so err on the high side of the recommended N application range Grai n yield (bu ushels/acre e) 170 150 130 110 90 70 Corn Yield Response to N Following Five Years of Soybean Average of Tillage Treatments 159 160 Arlington, WI 1987 to 1994 Low N 149 Rec N 143 145 137 139 139 133 119 108 106 106 104 7% 7% 22% 27% 30% 31% 28% BC A B A F B G DE G CD G CDE G E 50 CS 1C 2C 3C 4C 5C CC Source: Lauer Cropping Sequence C= Corn, S= Soybean, Number = consecutive year of corn
Rotation is more important in stress environments Yield Advantag ge of Rotat ted Corn (% %) 50 40 30 20 10 0-10 Weed outbreaks and species shifts Brown stem rot (Races A and B) Soybean cyst nematode Corn rootworm variant Control Treatments of CS and CC Arlington and Lancaster, WI 1985 2006 (n= 65) y = -0.21x + 46.45 R² = 0.38 40 60 80 100 120 140 160 180 200 220 Source: Lauer, unpublished Continuous Corn Yield (bu/acre)
Conclusions Mechanism for rotation effect is unknown Hypothesis #1: One factor causes effect. Hypothesis #2: Multiple factors cause effect and risk of expression depends upon the environment. The rotation effect lasts at most two years increasing grain yield 10 to 19% for 1C and 0 to 7% for 2C. At least two break years are needed to measure a response in the second continuous cropping year. A one year break using soybean reduces the rotation effect in the second continuous year. Adding a third crop does not improve corn yield, but does improve soybean yield. Tillage does not affect yield the first year following soybean, but improves yield 5% in the second year, and 9% in the third year. N fertilization response increases in 2C and 3C of the rotation, so err on the high side of the N application range. Modern corn hybrids and management practices have the same rotation response as older hybrids and practices. Crop rotation is even more important in stress environments. Continuous- versus rotated-corn results in yield advantages of 5 to 30% for rotatedcorn.
Jorge Cusicanqui Heather Darby Palle Pedersen Trenton Stanger Zhe Yan Justin Hopf Kent Kohn Thierno Diallo Keith Hudelson John Gaska Tim Wood Dwight Mueller Darwin Frye Johnny Pendleton Ed Oplinger Paul Carter Roger Higgs Larry Bundy Funding Sources: Wisconsin Corn Promotion Board, Wisconsin Corn Growers Association, Wisconsin Soybean Association, Wisconsin Soybean Marketing Board, Seed Companies, USDA-Hatch Photo by Justin Hopf
Thanks for your attention! Questions? 2008 Corn Conferences Rice Lake January 10 Richland Center January 22 Johnson Creek January 21 January 24-25, 25 2008 Kalahari Resort Wisconsin Dells, WI 19