Tamil Nadu Rice Research Institute, Aduthurai-612 101, India.
Application of herbicide influences the soil biological activity. The effect of use of pre-emergence herbicide, pendimethalin at 1.0 kg/ha on soil bacteria, fungi and actinomycetes was investigated in 5 cm surface soil at 0, 90, 180 days after herbicide application and at harvest under various irrigation methods. These were inhibitory to soil microflora. Generally thc population of microflora was high both under drip and surface system of irrigations. The populations of bacteria. fungi and actinomycetes were higher under hand hoeing and weeding and unweeded check as compared to herbicide treated plots in the initial stage of crop growth. The microbial population was subsequently restituted in herbicide treatment.
