Broad Bed + Mulch and Foliar Nutrition of KNO3 Alleviate Intra-Seasonal Moisture Stress in Rainfed Maize (Zea mays L)

Abstract

Rainfed maize production is highly vulnerable to intra-seasonal dry spells and moisture stress, which adversely affect physiological functions, microbial activity and yield. Conventional flat bed planting often intensifies stress impacts. However, improved land configurations, such as broad bed with mulch, combined with foliar nutrient sprays may enhance crop resilience and productivity. This study aimed to evaluate the combined effects of land configuration and foliar nutrient sprays on physiological responses, soil microbial activity and yield of maize under intermittent drought stress in rainfed systems. A 2-year field experiment (2023 and 2024) was conducted at ICAR–CRIDA, Hyderabad, India, using a split-plot design with three land configurations (broad bed + mulch, broad bed and flat bed) as main plots and five foliar spray treatments (control, water spray, 1% KNO₃, 2% urea and 0.2% nano urea) as subplots. Moisture stress significantly increased oxidative damage (proline, MDA) in flat bed + control plots, whereas broad bed + mulch minimised stress. Foliar application of 1% KNO₃ consistently improved physiological resilience, reducing canopy temperature and increasing chlorophyll and nitrate reductase activity. Soil microbial activity (DHA, microbial biomass carbon and beneficial microbial populations) was highest under broad bed + mulch, further enhanced by foliar KNO₃. The improved grain yield observed with 1% KNO₃ (4194–5288 kg ha⁻¹) compared to control, with broad bed + mulch yielding the highest cob weight (157.8–200 g) and grains per cob (456–519). Combining broad bed and mulch with foliar nutrition, especially 1% KNO₃, effectively reduces drought stress in rainfed maize by lowering oxidative stress, improving physiological efficiency, increasing microbial activity, and strengthening yield resilience. These integrated practices offer a sustainable strategy to mitigate intra-seasonal drought impacts and enhance productivity in water-limited dryland systems.