Alteration of period before the interference of soybean on presence of volunteer corn

Abstract

The aim of this work was to characterize the onset of weed interference in two soybean cultivars, with different growth cycle, under two conditions of corn plants infestation. The experimental design was split plot design composed by two factors: periods of coexistence of soybean with corn (no coexistence, coexistence during 14, 28 and 42 days after sowing (DAS) and throughout the soybean cycle) and  two corn densities: 10 plants m^-2 and 30 plants m^-2. The cultivar Fundacep 63RR had its growth altered in period equal or longer than 42 DAS with no relation to corn populations. The reduction in grain yield of soybean occurred at 28 DAS for 10 plants m^-2 density and 14 DAS for 30 plants m^-2. The cultivar Fundacep 59RR changed its morphological characteristics in period equal or longer than 28 DAS. With 30 plants m^-2 of corn the height and number of soybean branches changed at 60 DAP. For the same cultivar, the yield loss started at 42 DAS for 10 plants m^-2 of corn and 28 DAP for 30 plants m^-2