| Abstract: | A field study conducted for three crop years (June?–?July) from 1995?–?96 to 1997?–?98 at the Indian Agricultural Research Institute, New Delhi involving five rice-based cropping systems and six nutrient combinations indicated that rice?–?wheat?–?mungbean (RWM), rice?–?potato?–?mungbean (RPM), rice?–?rapeseed?–?mungbean (RRsM) and rice?–?clover (RC) cropping systems gave 0.7?–?1.0, 3.2?–?5.9, 0.2?–?2.2 and 1.5?–?3.6 t ha?1 yr?1, respectively, higher productivity and removed 7.9?–?22.6, 38.0?–?64.5, 53.0?–?61.8 and 51.4?–?66.1?kg ha?1 yr?1, respectively, more nitrogen, 2.3?–?7.1, 14.5?–?22.8, 3.8?–?7.2 and 17.3?–?21.7?kg ha?1 yr?1, respectively, more phosphorus and 1.6?–?11.4, 15.3?–?42.3, 8.2?–?22.7 and 40.8?–?57.8?kg ha?1 yr?1, respectively, more potassium than the rice?–?wheat (RW) cropping system which led to a net balance of +?151, +?58, ??153 and ??167?kg ha?1 of nitrogen, +?13, ??27, ??8 and ??59?kg ha?1 of phosphorus and ??549, ??551, ??558 and ??691?kg ha?1 of potassium after three cycles of RWM, RPM, RRsM and RC cropping systems, respectively against a net balance of +?201, +?26 and ??533?kg ha?1 of N, P and K, respectively in the RW cropping system. Application of FYM along with NPK in these cropping systems changed the negative balance of nitrogen and phosphorus into positive balance and reduced the negative balance of potassium by 151?–?378?kg ha?1. Application of P and K fertilizers along with nitrogen also helped in arresting the negative balance of P and K under different rice based cropping systems. These results thus indicate that balanced use of NPK and FYM plays a major role for sustaining the productivity of a cropping system. |
