Production potential, nutrient uptake, soil fertility and economics of soybean (Glycine max) - based cropping systems under organic, chemical and integrated nutrient management practices

A field experiment was conducted during 2004-05 to 2007-08 at Bhopal, Madhya Pradesh, to study the effect of organic, chemical and integrated (50:50) nutrient management (INM) practices on the productivity, nutrient up- take, soil fertility and economics of 4 soybean ( Glycine max (L.) Merr.) based cropping systems involving durum wheat ( Tr iticum durum Desf), mustard ( Brassica juncea L. Czern & Coss .), chickpea ( Cicer ar ietinum L) and isabgol ( Plantago ovata Fors k). The productivity of crops in these systems was higher in the integrated nutrient management compared to either chemical fertilizers or organic manures, in all the years. In the first year (2004- 05), the organic manure treatment recorded 7.8, 5.6, 9.4, 3.0 and 2.5 % reduction in the productivity of soybean, durum wheat, mustard, chickpea and isabgol crops, respectively, whereas in the fourth year (2007-08), the pro- ductivity of these crops was improved by 11.1, 1.1, 3.0, 4.2 and 11.2 % than chemical fertilizers. Among the treat- ments, soybean- durum wheat cropping system recorded the highest soybean equivalent yield (4.54 t/ha) under integrated nutrient management. Maximum uptake of N, P and K was recorded in integrated nutrient manage- ment and soybean- durum wheat cropping system. At the end of the 4 cropping cycles, application of organic ma- nures resulted in significantly higher soil organic carbon, available N, P and K than chemical fertilizers but was on par with the integrated nutrient management. Economic returns were the highest in the INM and soybean- du- rum wheat cropping system and they were similar between the treatments receiving organic manures and chemical fertilizers.