Effects of Annual Weeds on the Growth and Yield of Soybeans¹

Abstract

Synopsis In 15 experiments, yield reductions of soybeans in weed‐infested plantings averaged 3.7 bushels per acre or approximately 10% of weed‐free beans when weeds were grown the entire season. Foxtail reduced bean yields slightly less than smartweed or velvet leaf. Dry matter yield of above ground parts of soybeans and weeds combined approximated that of weed‐free beans alone. Effects of rainfall are discussed. Possible effects of uncontrolled factors are recognized.