International Journal of Environment and Climate Change

Nitrogen use efficiency is one of the sustainability criteria which get altered as a response to varied interventions like water conservation practices and source of nitrogen in rainfed agriculture. A two-year’ investigation was conducted to evaluate in-situ moisture conservation practices and different nitrogen sources for nitrogen uptake and NUE in rainfed sorghum on alfisols of the semi-arid region of India. The experiment was laid out in a split plot design replicated thrice. Main plot treatments were in-situ moisture conservation practices like conservation furrow (CF) and ridge and furrow (RF), while sub-plot treatments were different nitrogen sources like chemical fertilizers, farmyard manure (FYM), vermicompost (VC) and poultry manure(PM). Diverse agronomic indices viz., recovery efficiency, physiological efficiency, agronomic efficiency and partial factor productivity were derived to assess the NUE. The results demonstrated that CF and RF methods of in-situ moisture conservation exhibited equal response pertaining to N uptake, Soil N and nitrogen use efficiency. However, nitrogen uptake was higher through partial substitution of the recommended dose of nitrogen with PM (67.8 kg ha^-1), FYM (63.8 kg ha^-1) and VC (63.9 kg ha^-1) along with synthetic fertilizers in integration. Soil fertility in the form of mineral N (NH4-N + NO3-N) was improved by combined use of chemical and organic sources of N. Higher crop recovery efficiency, physiological efficiency, agronomic efficiency and partial factor productivity were higher with inclusion of organic manures, especially in integrated manner.  The experimental findings suggested that, in rainfed sorghum cultivation in semi-arid tropic of India, conjunctive use of 75% RDN through synthetic fertilizer and 25% RDN through PM or FYM or VC along with conservation furrow or ridge and furrow practice could be adopted for improved NUE.