Competitive Relationships in Variable Weed and Soybean Stands¹

Abstract

Synopsis Growth of annual weeds increased markedly and bean yield reductions became more severe with soybean stands of less than 9 to 11 plants per foot of row. Bean yield reductions were more severe when weeds were left until or after stage 7 (early August). With moderate weed infestations and moisture deficits during the growing season, soybean yield reductions were less than with adequate moisture. Foxtail and smartweed infestations reduced bean yields about equally. Dry matter yields of above‐ground plant parts of soybeans and weeds together were slightly higher than that of weed‐free beans.