Notes and Unique Phenomena

Timing, intensity, and frequency of biomass removal PREDICTING YIELD LOSS IN affects soybean yield. Yield reduction is less sensitive INDETERMINATE SOYBEAN FROM to biomass removal during vegetative growth because soybean can develop new leaf area that can compensate POD DENSITY USING SIMULATED for temporarily reduced assimilatory capacity. Singer DAMAGE STUDIES (2001) reported that yield reductions in indeterminate soybean from removing the top third of the plant at V5 were less than biomass removed at R4. Although J. W. Singer,* R. W. Malone, D. W. Meek, indeterminate soybean vegetative growth occurs until and D. Drake R5, creating new leaf area that increases assimilatory capacity directly competes with reproductive sink deAbstract mand. Fehr et al. (1977) reported that yield of determiDeveloping relationships between seed yield and pod density can nate cultivars was affected more than indeterminate be useful for predicting yield loss in soybean [Glycine max (L.) Merr.] from 100% defoliation when defoliation occurred from damaged by deer (Odocoileus virginianus). The objectives of this R2 through R6. However, average yield loss from halfresearch were to (i) develop a modeling tool using differences between plant cutoff was similar for determinate (33%) and indebiomass removal treatments and controls for pod density and seed terminate (34%) cultivars, but there was a significant yield to quantify yield loss and (ii) assess the tool using double crossinteraction with growth stage (Fehr et al., 1977). validation. Model development using linear and polynomial exponen-