Effect of cotton crop-residue management practices and levels of nitrogen and potassium on rice (Oryza sativa) and succeeding blackgram (Phaseolus mungo) in rice–blackgram cropping system

A field experiment was carried out at Agricultural College and Research Institute, Madurai, during the winter (rabi) seasons of 2000 and 2001, to study the effect of cotton (Gossypium sp.) crop residue management practices and levels of inorganic fertilizer N and K on rice (Oryza sativa L.) and succeeding blackgram (Phaseolus mungo L.) in rice–blackgram cropping system. Incorporation of cotton stalks @ 5 tonnes/ha with Trichoderma viride in rice crop significantly improved the growth parameters, yield attributes and yield of rice. Maximum residual effect was observed with the incorporation of cotton stalks @ 5 tonnes/ha + Trichoderma viride, that resulted in the marked improvement in the growth, yield attributes and yield of succeeding blackgram. Similar yield trend was seen by increasing levels of N and K fertilizers in rice and blackgram.