Precision Nutrient Management for Higher Nutrient Use Efficiency and Farm Profitability in Irrigated Cereal-based Cropping Systems

Abstract

In the past, blanket region-based fertilizer recommendations prescribed to farmer’s that did not take into account the variations in the indigenous nutrient supply from the specific fields have led to higher production costs, diminishing yield and factor productivity, and increasing greenhouse gas emissions. Therefore, precision fertilizer recommendations that address the need-based crop requirements have been urgently needed. Site-specific nutrient management (SSNM) along with modern agronomic management practices may increase yields and nutrient use efficiency by optimizing the balance between nutrient supply and demand. In recent studies across large numbers of locations in rice/wheat-based systems in the Indo-Gangetic Plains (IGP) of India, SSNM has led to 8-12% increases in grain yields compared to farmers’ fertilizer practices/state recommended doses of fertilizers (RDF). The adoption of SSNM significantly increased the net returns by Rs. 2,500-3,200 ha-1 over farmers’ fertilizer practice by saving money on costly fertilizer inputs. Optical sensor (GreenSeeker)-based SSNM saved 20-30 kg N ha-1 without affecting grain yield under conservation agriculture (CA)-based cereal systems compared to recommended dose of fertilizers (RDF). Efficient management of N-fertilizers reduced N2O emissions by avoiding N losses via volatilization, leaching and denitrification. Site-specific nutrient management provides opportunities for enhancing crop productivity, profitability and nutrient use efficiencies (NUE) across the different ecologies. Drip irrigation system (sub-surface drip irrigation) improved the N-use efficiency by 20% over flood irrigation system in rice/maize-based systems that helped in increasing the farm profitability by saving on N-fertilizer use and water in rice-wheat/ maize-wheat systems.