Performance of soybean (Glycine max)-based cropping sequences under organic, inorganic and integrated nutrient supply systems in a Vertisols

Experiments were conducted at Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh during 2004–05 to 2008–09 (five years) with the objective to develop efficient crop and soil management options for organic farming and their after effects on productivity and sustainability of 4 soybean {Glycine max (L.) Merr.}-based cropping systems with wheat {Triticum aestivum (L.) emend. Fiori & Paol}, berseem (Trifolium alexandrium), mustard {Brassica juncea (L.) Czern & Coss.} and chickpea {Cicer arietinum (L.)} under organic, inorganic and integrated nutrient supply system. In the first year of study, inorganic nutrient supply system (INS) recorded markedly higher yield in all the cropping systems. However, from the second year onwards, integrated plant nutrient supply system (IPNS) produced higher yield in all the four cropping systems studied and found better than INS. Production in all the four cropping systems with organic manuring alone (ONS) was significantly lower than with INS, although the differences decreased as the cropping systems progressed over years. Organic farming system can be profitable only if a price premium of 20% or above is provided. From the view point of soil fertility, IPNS was the best followed by organic nutrient supply system (ONS), while the application of chemical fertilizer alone (INS) recorded the lowest values of available N, P and K and bacterial count.