Interference between velvetleaf (Abutilon theophrasti Medic.) and soybean (Glycine max (L.) Merr.) II. Population dynamics

Summary Two field experiments were conducted to determine the effect of changes in Abutilon theophrasti and soybean population numbers through the growing season on soybean dry weight and seed yields. Whether in mixtures or monoculture, the rate of mortality of both species was constant through the growing season. In general, the greater the initial population of either species the greater the rate of mortality through the growing season. Evidence presented supports the hypothesis that A. theophrasti has the adaptive ability of differential mortality at different populations when in mixed stands with soybean and when grown alone and that soybean lacks this ability when mixed with A. theophrasti. This results in smaller, less productive, individual soybean plants.