No-tillage soybean performance in cover crops for weed management in the western Corn Belt

M. M. Williams; D. A. Mortensen; J. W. Doran

ABSTRACT:

Frequency of soil moisture depletion and subsequent crop yield reduction resulting from water use by cover crops is unclear. Effects of cover crop residues and imgation on soybean emergence, canopy volume, grain yield, and soil moisture in eastern Nebraska were determined. Cover crop treatments included five common species and a bare soil control. Precipitation treatments included rainfed conditions and weekly irrigation events of 18 mm (0.7 in) in June and July. Above-normal May rainfall in 1995 and 1936 resulted in similar percent volumetric soil water contents (%VSWC) in the surface 15.2-cm (6.0-in) soil layer. Soybean emergence was unaffected by residue dry matter levels below 3,170 kg/ha (2,830 lb/ac) . Early-emon soybean growth was similar across all treatments; however, cover crop biomass greater than 2,170 kg/ha (1,940 lb/ac) reduced soybean canopy volume 33 to 44% during mid-season droughts. Yields were highest when stand densities were maintained and weed were suppressed. This research develops a greater understanding of how cover crop residues influence soybean performance, ultimately reducing reliance on postemergent herbicide use for weed control in no-tillage systems.

Footnotes

Martin M. Williams II is graduate research assistant, and David A. Mortensen is professor, Department of Agronomy, University of Nebraska-Lincoln, Lincoln, Neb.; and John W. Doran is soil scientist with the US. Department of Agriculture's Agricultural Research Service (USDA-ARS), Lincoln, Neb. They thank R Drijber, J. Lindgurist, and A. Martin for discwsion, and E. Anderson, G. Lesoing, and D. Radach for technical assistance. This research was a joint project of the University of Nebraska Agricultural Research Division and the USDA-ARS Journal series no. 12043.
Copyright 2000 by the Soil and Water Conservation Society

This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.