INFLUENCE OF LONG TERM USE OF ORGANIC AND INORGANIC MANURES ON SOIL FERTILITY AND SUSTAINABLE PRODUCTIVITY OF SOYBEAN-WHEAT SEQUENCE IN VERTISOLS OF MADHYA PRADESH

Long term integrated nutrient management trails in Soybean-Wheat sequence in vertisols conducted for many years at J.N. Krishi Vishwa Vidyalaya, Research Farm, Jabalpur revealed that highest sustainable yield index (SYI) was observed in 100% NPK + FYM, while lowest was observed in 100% N treatments in both crops. However, the mean grain yield was not significantly influenced by different nutrient management practices except in case of control (no manure and fertilizers) and 100% N alone treatments. The continuous application of recommended dose of phosphorus fertilizers to soybean (60 kg ha-1) and wheat (80 kg ha-1) crop every year resulted in substantial built  up of available phosphorus up to 39 kg P2O5 ha-1  from initial level in the year 1972 i.e. 7.6 kg P2O5 ha-1.