Production potential, soil health, water productivity and economics of rice (Oryza sativa)-based cropping systems under different nutrient sources

A field experiment was conducted during 2004–05 to 2008–09 at Jabalpur, Madhya Pradesh to study the effect of chemical fertilizers, organic manures (ONM) and integrated (50:50) nutrient management (INM) practices on the production potential, soil fertility, water productivity and economics of 4 rice (Oryza sativa L.)- based cropping systems involving durum wheat (Triticum durum Desb.)-sunhemp (Crotolaria juncea L.), potato (Solanum tuberosum L.)-okra (Abelmoschus esculentus L.), berseem (Trifolium alexandrium L.) and vegetable pea (Pisum sativum L.) and sorghum (Sorghum bicolor L. Moench). The productivity of crops in these cropping systems was higher when chemical fertilizer was used compared to ONM or INM in all the years of experimentation. In the initial years, ONM recorded a significant reduction in yield. Of the different rice based cropping systems, rice-potato-okra gave the highest rice equivalent (REs), while rice-wheat-GM gave the least REs. At the end of 5 cropping cycles, application of organic manures resulted in higher soil organic carbon, available N, P and K than the chemical fertilizers. Maximum beneficial micro-organisms were recorded under organic nutrient management (ONM) after completion of 5 crop cycles and the bulk density of soil was also lowered significantly in ONM. The B:C ratio was higher for chemical fertilizers in case of rice-durum wheat-green manuring (3.6) and rice-potato-okra (3.1) due to lesser cost of cultivation.