Integrated Nutrient Management Stabilizes Rice Yield and Maximizes Water Productivity Under Deficit Irrigation in Arid Punjab, Pakistan

Abstract

Water scarcity threatens rice production in arid regions. This study evaluated three irrigation intervals (continuous submergence, 3-day, 6-day) and four nutrient treatments (control, recommended NPK, farmyard manure [FYM] only, NPK+FYM) on rice yield, water productivity, and soil health in Dera Ghazi Khan, Punjab, Pakistan. NPK+FYM (integrated nutrient management, INM) showed remarkable resilience under deficit irrigation, with only 10% yield reduction under 6-day interval (4.4 t ha⁻¹) compared to submergence (4.9 t ha⁻¹), whereas other treatments declined 13-25%. The highest benefit-cost ratio (2.73) occurred under severe deficit with INM. The 3-day interval with INM saved 33% water while achieving 96% of maximum yield (BCR=2.52). Under 6-day interval, INM attained the highest irrigation water productivity (0.70 kg m⁻³), 79% above submerged INM. FYM-amended plots increased soil organic matter (120-200%) and reduced pH (8.19→7.68). Irrigation × nutrient interaction was non-significant for yield (p=0.998). We conclude that 50% NPK + 50% FYM with 3-day interval optimizes yield stability, water productivity, and soil health in arid rice systems.