- Agronomic: corn, soybeans, wheat, hay
- Animal Production: feed/forage
- Crop Production: crop rotation, application rate management, ridge tillage
- Education and Training: farmer to farmer
- Farm Business Management: whole farm planning, farm-to-institution, agricultural finance
- Pest Management: biological control, physical control, cultivation
- Soil Management: soil analysis
An experiment was started in 1991 to establish a crop rotation system where four single crop production components (ridge tillage; 3-crop wheat-corn-soybean; narrow (15′ wide), alternate strips; and legume interseeding) could be studied as an integrated farming system. The rotations (continuous corn, corn-soybean, wheat-corn-soybean where the wheat is interseeded with either Nitro alfalfa, vetch, or nothing) were set up in 1991 on a Webster clay loam (Typic Haplaquoll) on the Lynn Sorenson farm in Freeborn Co. In 1992, nitrogen rates of 0, 40, 80, and 120-lb/A were applied to corn following soybean, wheat, wheat + alfalfa, and wheat+ vetch to determine the N credit due to fixation by the legumes. Band applications of reduced rates of herbicide were applied to both corn and soybean. Mechanical weed control and ridge building were accomplished through cultivation. Yields and grain moisture of wheat, corn and soybean were taken in 1992 to evaluate the border vs. inside row effects of the strips, the interseeded legumes, and the response to N as effected by the cropping systems. Data on vetch and alfalfa yields, weed seedbank counts, root ratings and lodging to evaluate corn rootworm (CRW), tunnel counts to assess European corn borer (ECB) damage, and soybean cyst nematode (SCN) egg counts were taken. Yield data obtained in this second year, based on the assumption that the center two rows of a 6-row strip or the center 7 rows of the 21-row wheat strip represent a “whole-field” yield, showed: (1) 4% higher corn yields and 14% lower soybean yields compared to a “whole-field” average when grown in alternate strips and (2) 7% higher corn yields, 5% lower wheat yields, and 8% lower soybean yield when grown in the 3-crop strip rotation compared to a “whole-field.” Excessive spring re-growth of Nitro alfalfa and hairy vetch resulted in significant competition to the corn, resulting in stunted early growth, delayed maturity, and 20% lower corn yield compared to following wheat without a legume. Pest evaluation showed very little evidence of CRW or ECB activity. Soybean cyst nematode populations were considerably lower in the 3-crop system (no soybeans in 1991 or 1992) compared to those systems that included soybean in either 1991 or 1992. Weed counts indicated substantially more small grass and broadleaf weeds in corn following wheat in the 3-crop system compared to corn following soybean in the 2-crop rotation.
1) Determine the production and economic impact of wheat introduced into a conventional corn-soybean alternate strip rotation in a ridge tillage system.
2) Determine the potential of this 3-crop rotation to minimize insect, nematode, and weed pressures and thus reduce pesticide use.
3) Determine the effect of interseeding legumes with wheat on the potential fertilizer N savings, N availability to corn, and economics in a ridge tillage system.
4) Measure the border row vs. inside row effects of each crop on yield, pest incidence, N utilization, land utilization, and production economics.
5)Evaluate the ability of potential soil tests to predict available soil N for corn following soybeans and following wheat with and without interseeded legumes.