Combined application of nano-DAP and conventional fertilizers improved agronomic and economic performance of rainfed maize, nutrient and energy use efficiency

Efficient nitrogen (N) and phosphorus (P) management enhances crop yield while minimizing environmental impact. Nano-fertilizers are reported to ensure sustained nutrient release, optimize nutrient absorption and improve nutrient use efficiency, leading to higher crop productivity and profitability. A two year field trial was conducted under semi-arid conditions in India to evaluate the effect of foliar-applied nano-DAP on the growth, productivity, profitability and nutrient use efficiency of rainfed maize. The treatments comprised conventional fertilizers at varying N and P levels [0, 50, 75, and 100% recommended dose of N and P] with and without foliar application of nano-DAP. Application of 100% recommended NPK (90-45–45 N-P-K kg ha -1 ) through conventional fertilizers along with foliar sprays of nano-DAP (N 100 P 100 K+ nano-DAP) resulted in higher grain yield (3058 kg ha -1 ) and economic returns (US $ 473 ha -1 ). Notably, the N 75 P 75 K + nano-DAP treatment produced yield and economic returns comparable to those obtained with 100% recommended NPK, either alone or in combination with nano-DAP. This demonstrates that two foliar sprays of nano-DAP can reduce N and P inputs by 25% without compromising on yield or profitability. Higher agronomic use efficiency of N (26.9%) and P (48.4%), apparent recovery efficiency of N (42.6%) and P (11.3%) were also observed under N 75 P 75 K + nano-DAP. Furthermore, N 75 P 75 K + nano-DAP treatment reduced greenhouse gas (GHG) emissions by 24.5% and energy consumption by 15.4%, highlighting its potential for sustainable maize production with reduced environmental impact compared to N 100 P 100 K treatments.