Submitted to: Soil/Water Research, Progress Report
Publication Type: Research Notes
Publication Acceptance Date: February 12, 1999
Publication Date: N/A
Interpretive Summary: Crop rotation improves soil structural stability, increases crop water use efficiency, increases soil organic matter levels, improves nutrient use efficiency, provides better weed control, and disrupts insect and disease cycles. Research conducted previously at the Eastern South Dakota Soil and Water Research Farm has demonstrated that mineral nutrient accumulation and grain yield were greater in corn grown under annual rotation with soybean than in corn grown in monoculture. We were interested in determining whether a corn-soybean-wheat/alfalfa-alfalfa rotation would have similar beneficial effects on soil fertility and crop mineral nutrition. Our experimental objectives were to investigate the effects of complex crop rotation on soil fertility and corn mineral nutrient composition. Understanding the complex interactions of soils, plants, and management practices is a first step towards development of agricultural systems that sustain food and fiber production.
Technical Abstract: Crop rotation treatments were established in the 1990 growing season at the Eastern South Dakota Soil and Water Research Farm near Brookings, SD. Treatments were a continuous corn monoculture (CC), a corn-soybean rotation (CS) and a corn- soybean-wheat/alfalfa-alfalfa rotation (CSGL). Soil samples (0 to 12 inches depth) were taken at the 6th leaf stage of corn crop development (June 12, 1998) using a soil auger. Soil water at the one to two foot depth was also measured using a neutron probe on June 5, 1998. Corn leaves were sampled for dry weight and mineral nutrient concentration when shoot development reached the 6th leaf stage (June 12, 1998). The CSGL rotation treatment had significantly higher levels of NO3-N and Fe as well as lower levels of P than the CC monoculture. Corn plants following alfalfa in the CSGL rotation had significantly higher N and Fe concentrations than plants following soybean (CS) or corn (CC). The lower soil P level seen after alfalfa was not accompanied by decreased leaf P concentrations in the corn crop. Our data show a beneficial effect of crop rotation on soil N and Fe fertility as well as on corn mineral nutrition early in the growing season. A mechanistic understanding of this beneficial effect could be used as a basis to help design and evaluate more diverse crop rotations that sustain soil and crop productivity.