ARS | Publication request: EVALUATION OF 2- AND 4-YEAR CROP ROTATIONS WITH FOUR MANAGEMENT STRATEGIES IN MINNESOTA

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 20, 2003
Publication Date: June 20, 2003
Citation: Porter, P.M., Huggins, D.R., Perillo, C.A., Quiring, S.R., Crookston, R.K. Organic and other management strategies with two- and four-year crop rotations in Minnesota. Agronomy Journal. 2003. v. 95. p. 233-244.

Interpretive Summary: In the USA, the corn-soybean rotation is dependent on high levels of off- farm inputs such as pesticides and fertilizers. Little research data exists comparing conventional production practices with practices involving reduced off-farm inputs and expanded rotations. Two field trials initiated in 1989 near Lamberton MN evaluated a 2-yr corn-soybean rotation and a 4-yr rcorn-soybean-oat/alfalfa-alfalfa rotation under four management strategies The four management strategies involved zero(ZI), low(LI), high(HI), and organic(OI)inputs. One trial (V1) was on land with a history of no fertilizer and pesticide usage. The other trial (V2) was on land with a history of conventional fertilizer and pesticide usage. From 1993 through 1999, corn yield in the 2-yr HI strategy was 8.96 Mg ha-1 in V1 and 8.72 Mg ha-1 in V2. Corn yield in the 4-yr HI strategy was 4 percent less than in the 2-yr HI strategy in V1, whereas in V2 the yields were not different. Soybean yield in the 2-yr HI strategy was 2.90 Mg ha-1 in V1 and 2.74 Mg ha-1 in V2. Soybean yield in the 4-yr compared with the 2-yr HI strategy was 3 percent greater in V1 and 6 percent greater in V2. These results suggest soybean was more responsive than corn to the expanded rotation length in the HI strategy. Corn yield in the 4-yr OI strategy compared with the 2-yr HI strategy was 9 percent less in V1 and 7 percent less in V2, while soybean yield in the 4-yr OI strategy compared with the 2-yr HI strategy was 19 percent less in V1 and 16 percent less in V2. By comparing yields of the 2-yr and 4-yr rotations for each management strategy, this research documents off-farm inputs mask beneficial yield effects of the expanded crop rotation.

Technical Abstract: In the USA, the corn-soybean rotation is dependent on high levels of external inputs. Little research exists comparing conventional production practices with practices involving reduced external inputs and expanded rotations. Two trials initiated in 1989 near Lamberton MN evaluated a 2-yr corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation and a 4-yr corn-soybean-oat (Avena sativa L.)/alfalfa (medicago sativa L.)-alfalfa rotation under four management strategies. The four management strategies were zero(ZI), low(LI), high(HI), and organic(OI)inputs. One trial (V1) was on land with a history of no fertilizer and pesticide usage. The other trial (V2) was on land with a history of conventional fertilizer and pesticide usage. From 1993 through 1999, corn yield in the 2-yr HI strategy was 8.96 Mg ha-1 in V1 and 8.72 Mg ha-1 in V2. Corn yield in the 4-yr HI strategy was 4 percent less than in the 2-yr HI strategy in V1, whereas in V2 the yields were not different. Soybean yield in the 2-yr HI strategy wa 2.90 Mg ha-1 in V1 and 2.74 Mg ha-1 in V2. Soybean yield in the 4-yr compared with the 2-yr HI strategy was 3 percent greater in V1 and 6 percent greater in V2. These results suggest soybean was more responsive than corn to the expanded rotation length in the HI strategy. Corn yield in the 4-yr OI strategy compared with the 2-yr HI strategy was 9 percent less in V1 and 7 percent less in V2, while soybean yield in the 4-yr OI strategy compared with the 2-yr HI strategy was 19 percent less in V1 and 16 percent less in V2. By comparing yields of the 2-yr and 4-yr rotations for each management strategy, this research documents external inputs mask beneficial yield effects of the expanded crop rotation.