Effects of barnyardgrass on rice plants at different levels of nitrogen and phosphorus fertilizers

Abstract

Two out-of-door experiments were carried out in boxes having 47 kg of soil to determine the effects of Echinochloa crus-galli (L.) Beauv. (barnyardgrass) on growth and yield of rice plants. The following variables were studied in a factorial combination: nitrogen fertilization x barnyardgrass population density, and phophate fertilization x barnyardgrass population density. The results showed that fertilizations (N or P₂O₅) had not influenced the interaction weed x crop. At all densities, the weed reduced the phytomass, tillering, number and weight of panicles of rice plants. All growth parameters of rice plants were decreased with increasing weed density and a linear regression was the best fit for these results.