Fertigation Effects on Nutrient Use Efficiency, Energy Productivity, and Economics of Coconut (Cocos nucifera L.) Cultivation in the Eastern Indo-Gangetic Plains of South Asia

Abstract

ABSTRACT Drip fertigation has potential to reduce fertilizer dose in comparison to surface application in coconut (Cocos nucifera L.) by increasing its’ use efficiency in the Eastern Gangetic plains of South Asia. A long-term field experiment (2007–2013) was conducted on Inceptisol to evaluate 100% of the soil test-based recommended fertilizer dose (RDF; N:P2O5:K2O applied at 500:250:750 g palm−1 year−1) in soil with ring basin irrigation as conventional, 100%, 75%, 50%, 25%, and 0% of the RDF through drips. The fertigation level of 75% RDF resulted in 32%, 19%, 39%, and 16% higher copra yield, energy productivity, net return, and benefit-cost ratio, respectively, over conventional. Increasing trend of nutrient use efficiency was observed with decreasing dose of N, P and K. Use efficiencies decreased from 50.4 kg copra kg−1 N, 230.7 kg copra kg−1 P, and 40.5 kg copra kg −1 K (with 25% of the RDF through drip) to 6.1 kg copra kg−1 N, 27.8 kg copra kg−1 P, and 4.9 kg copra kg−1 K (with 100% RDF through ring basin irrigation). Fertigation with 75% RDF in drip had the highest copra yield (3.19 t ha−1), energy output (206082 MJ ha−1), energy productivity (187 g copra MJ−1), net returns (US $ 3073 ha−1), and benefit–cost ratio (2.36) compared to others.