Analysis of growth and efficiency of water use by soybeans, beans and weeds

Abstract

The objective of this study was to evaluate the efficiency of uptake and use of water by cultures of soybeans, Glycine max, Glycine max (L.) Merril, beans, Phaseolus vulgaris L. and the weed species Euphorbia heterophylla (resistant and susceptible to ALS enzyme inhibiting herbicides), Bidens pilosa and Desmodium tortuosum, as well as to evaluate the routing of photoassimilates and the length of their cycles. None of the weed species evaluated completed a cycle before the bean harvest, which was the plant that used the water furnished at the beginning of the cycle most efficiently. B. pilosa was the species that directed the greatest proportion of photoassimilates into root formation during the vegetative phase. Soybeans presented the highest daily biomass accumulation rates and highest water use efficiency during the whole cycle. D. tortuosum was the most efficient weed species in capturing and using water in the vegetative phase, whereas B. pilosa was after flowering. E. heterophylla biotypes were competitively equivalent