Water-energy-food-GHG nexus-based optimization of irrigation and nitrogen strategies for sustainable intensification of Indian mustard in hot arid region of India

Abstract

Water, energy, food, and environment are strongly interconnected in agricultural systems, and understanding these linkages is essential for sustainable crop production. This study evaluated the inter-linkage among water-energy-food-greenhouse gas (WEFG) dimensions in Indian mustard under varying irrigation, nitrogen (N) rates and bio-regulator (BR) application using WEFG framework to identify resource-efficient and environmentally-sound management practices. A three-year field experiment was conducted in arid region of India with three irrigation levels [full (FI, 100 % ETc), moderate deficit (MDI, 70 % ETc), severe deficit (SDI, 40 % ETc)], three N rates (40, 80, 120 kg N ha⁻¹), and three BR treatments [without BR, thiourea (500 ppm), salicylic acid (0.5 mM)]. Water and energy use, yield, profitability, resource-use efficiency and CO₂-eq emissions were quantified and integrated through WEFG Nexus Index (WEFGNI). Irrigation accounted for 95 % of water and 37–66 % of energy use. FI produced highest yield but substantially increased water/energy use and emissions, while SDI reduced resource consumption and emissions but caused substantial yield/profit losses. MDI reduced water (∼25 %) and energy (20–40 %) consumption with negligible yield loss (≤4 %), achieving higher resource use efficiencies. Higher N rates under FI and MDI enhanced yield/profitability but also enhanced emissions, while BR application enhanced productivity, profitability and efficiency particularly under MDI and SDI. The combination of MDI, 120 kg N ha⁻¹, and BR application achieved highest WEFGNI, indicating optimal balance among productivity, efficiency and environmental performance. The WEFG framework effectively capture trade-offs and synergies across nexus dimensions, offering a tool to guide sustainable crop management strategies aligned with the SDGs.