Repeated Biomass Removal Affects Soybean Resource Utilization and Yield

Abstract

Soybean [Glycine max (L.) Merr.] producers in many regions of the USA are confronted with significant yield losses because of crop damage from white‐tailed deer (Odocoileus virginianus). Our objectives were to quantify soybean resource utilization and yield responses to variety, row spacing, and simulated repeated biomass removal. Field research was conducted in 2000 and 2001 on a Quakertown silt loam soil (fine‐loamy, mixed, mesic Typic Hapludult) near Pittstown, NJ. Biomass removal during early vegetative and vegetative/reproductive growth extended the soil wetness duration index on average by 1.5 and 2.9 d compared with the control from the 0‐ to 30‐ and 30‐ to 60‐cm soil depths in 2000 and by 5.1 and 2.1 d in 2001. Biomass removal during early vegetative growth delayed pod maturity up to 7 d compared with the control, but biomass removal during reproductive growth hastened pod maturity by as much as 3 d. Averaged across row spacing and biomass removal, variety ‘APK394NRR’ yielded 12 and 24% lower than ‘93B53’ in 2000 and 2001. In 2000, averaged across variety and biomass removal, the 20‐ and 41‐cm row widths yielded 19 and 16% less than the 76‐cm row width. Averaged across variety and row spacing, all biomass removal treatments lowered yield compared with the control except the midvegetative/early reproductive treatment in 2001 (661 vs. 663 g m−2). The greatest yield reductions occurred (up to 89%) when biomass was removed repeatedly during vegetative and reproductive growth. Management implications for soybean producers include variety selection and row spacing to diminish the effects of deer damage.