Long-term effect of tillage and nitrogen sources on the sustainability and productivity of maize (Zea mays)-wheat (Triticum aestivum) cropping system under rainfed conditions

Field experiments were conducted during 2000-06 to assess the impact of tillage practices and different nitrogen sources on the productivity potential of maize (Zea mays L.)-wheat (Triticum aestivum L. emend Fiori & Paol) cropping sequence on long-term sustainable basis under rainfed conditions. Modified reduced tillage (RT II) resulted in significantly higher mean maize grain yield (2 199 kg/ha) with 8.3 and 14.6% yield superiority over the conventional tillage and reduced tillage (RT 1). Application of recommended dose of nitrogen through inorganic source recorded significantly higher mean grain yield of 2 245 kg/ha in comparison to application of recommended dose of nitrogen through compost and integration of inorganic and organic sources (50 : 50 basis). Conventional tillage was found to be superior for attaining higher grain yield of wheat (2 525 kg/ha) under rainfed conditions. However, when RT I was integrated with post-emergence herbicide-based weed control (RT 11), significant improvement in yield (9.6%) was noticed and it was found to be at par with conventional tillage. The lowest CV (25.1%) and highest sustainable yield index (SYI) (0.61) recorded with RT H as against the CV of 27.9% and SYI of 0.54 under conventional tillage indicated its more reliability and optimum tillage for not only resource conservation but also for attaining higher productivity under rainfed conditions. Application of 100% N through organic source resulted in significantly lower wheat yield (2 248 kg/ha). However, substituting the source of N from organic to inorganic, a significant improvement in yield was noticed, which was found to be 10.9% with 50% substitution while with 100% substitution it was 10.7%.