Long-term effect of integrated nutrient management in rice (Oryza sativa)wheat (Triticum aestivum) Cropping system

Abstract

A field experiment was conducted on permanent manurial trial, initiated during the rainy ( kharif) season 1985 at JNKVV, Jabalpur, to evaluate the long-term impact of fertilizer and manure and their integration on yield trends, production efficiency and soil-quality parameters and their inter-relationship with sustainable yield index (SYI) un- . der rice ( Or yza sativa L )wheat [ Tr iticum aestivum (L.) emend. Fiori & Paol.] cropping sequence. The treatment 50% NPK + 50% N substituted through farmyard manure (FYM) to rice and 100% NPK to wheat provided the high- est wheat-equivalent yield (WEY 8.01 t/ha) with net monetary returns ( 42.7 103/ha) and recorded 430% higher system productivity over the control. The next best treatment was 50% NPK + 50% N substituted through green leaf manure (GLM) of sunhemp ( Sesbania aculeata L.) to rice and 100% NPK to wheat gave higher WEY of 7.97 t/ ha with net monetary returns (42.1 103/ha). The treatment 50% NPK + 50% N substituted through farm yard ma- nure (FYM) to rice and 100% NPK to wheat and 50% NPK + 50% N substituted through GLM to rice and 100% NPK to wheat also increased organic carbon (7.6 g and 7.9 g/kg), available N (282 and 292 kg/ha), P O (15.4 and 2 5 17.2 kg/ha), K O (466 and 488 kg/ha), S (8.4 and 8.5 kg/ha) and Zn (0.43 and 0.45 kg/ha), sustained soil pH (7.49 2 and 7.48) and electrical conductivity (EC) (0.58 and 0.63 dS/m) and lowered the bulk density (1.27 and 1.27 g/ cm3). In the treatment receiving 100100% NPK through fertilizer to both rice and wheat crops, the total productiv- ity was higher (7.72 t/ha). The higher sustainable yield index (0.83) was observed with 50% NPK + 50% N substi- tuted through GLM to rice and 100% NPK through fertilizer to wheat crop. Maximum beneficial micro-organisms, viz. fungi, bacteria, azotobacter, phosphorus solubilizing bacteria and actinomycetes were recorded with the inte- grated nutrient practices. Negative trend of net monetary returns was noted with control plot.