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
