Short-term practice of deficit irrigation and nutrition influences soil–root interface, and water use efficiency of winter fodder corn in semi-arid region

Abstract Water scarcity is a global concern due to climate change induced irregular rainfall, and unsustainable water management practices. This study assessed the interaction of deficit irrigation and nutrient levels on soil-roots interface, water use efficiency (WUE), and seed yield in winter fodder corn. Three-year experiment (2018–2021) in Central India consists three irrigation levels (I1, 25% soil moisture depletion, full irrigation; I2, 50% depletion; I3, 75% depletion, severe deficit) and four nutrient rates (N1, no NPK; N2, N 100, P 40 kg ha –1 ; N3, N 120, P 60, K 40 kg ha –1 ; N4, N3 + Zinc sulphate 20 kg ha –1 ), in a split-plot design with three replications. Moderate deficit irrigation (I2) with higher nutrient rates (N4) favored corn root growth by decreasing soil bulk density (by 2.2%), while increasing soil carbon stock (11.19 Mg ha −1 ) and available nutrients (N, P, K) in the upper (0–15 cm) soil layer. This combination enhanced root growth, resulted in longer roots (20.65–23.09%), with higher volume (43.44–69.88%), surface area (41.65–43.90%), number of crown roots (31.84–53.36%), and dry weight (34.61–42.81%). Additionally, I2 × N4 improved WUE (36.32%), seed yield (39.09%) and stover yield (21.20%) allowing for 26.08% water conservation, while increasing soil organic carbon (by 11.19%) compared to full and severe deficit irrigation. Moderate deficit irrigation with optimum nutrients offers a viable strategy to augment WUE and seed yield in fodder corn for water-scarce regions. The study underscores the detrimental effects of excessive irrigation on soil and crop roots.