Influence of weed management practices on soil microbial populations, soil nutrient status and biological yield of aerobic rice (Oryza sativa L.)

Abstract

Herbicide application has become a major breakthrough in agricultural productivity in the whole world since its benefit has been overwhelming over the years. Nevertheless, its harmful impact on the non-target soil microorganisms which plays important role in organic matter decomposition, N and nutrient recycling. The herbicides used in rice grown under aerobic condition may affect the biological equilibrium of the soil and thus affect the nutrient status, health and productivity of the soil. To study the effect of herbicides on soil microbial population in aerobic rice cultivation, a field experiment was carried out at the Zonal Agricultural Research Station (ZARS), University of Agricultural Sciences, GKVK, Bengaluru during 2017 to study the effect of different weed management practices on soil microbial population, soil chemical properties, available soil nutrients and biological yield of aerobic rice. Eleven weed management treatments were attemptedviz.,stale seedbed techniques, different mulching practices, application of pre and post-emergence herbicides, intercultivation and hand weeding. The results showed that there was no ill effect from different weed management treatments on the soil microbial population viz., fungi, bacteria and actinomycetes after harvest of rice. The reduced weed density and dry weight in the superior treatments reduced the loss of nutrients from soil thus helped in improving the soil available nutrient status after harvest. All weed management practices in combination with herbicides registered markedly higher biological yield over the weedy check. Introduction