| Sumario: | The use of residual soil moisture for post-rainfall cropping offers a promising pathway to enhance agricultural productivity, food security, and climate resilience in rainfed farming systems. In Ethiopia, where irrigation access remains limited and rainfall variability is high, the potential of residual soil moisture to support post-season legume production remains poorly quantified. This study assesses the spatiotemporal availability of residual soil moisture and its capacity to meet crop water requirements for nine commonly grown legume crops, including chickpea, lentil, cowpea, mung bean, soybean, field pea, common bean, faba bean, and grass pea across Ethiopia’s rainfed agricultural areas. Residual soil moisture dynamics during the early dry season (October–January) were characterized using GLDAS Noah soil moisture data (1981–2024), examining long-term means, interannual variability, and trends. Crop water requirements were estimated as crop evapotranspiration (ETc) using the FAO-56 Penman–Monteith formulation driven by ERA5-Land meteorological data, combined with growing stage-specific crop coefficients. A stage-dependent soil water balance (bucket) model with variable rooting depth was implemented to simulate daily root-zone soil moisture. Seasonal Soil Water Satisfaction Index (SI) and Probability of Soil Moisture Stress were derived to quantify the adequacy and reliability of soil water supply relative to crop demand. Results reveal strong west–east gradients in residual soil moisture, with higher and more stable moisture in western highlands and increasing moisture stress toward eastern lowlands. Mid-season growth stages consistently exhibited the largest water deficits across crops. Legumes such as mung bean, common bean, cowpea, and grass pea showed higher water satisfaction and lower stress probabilities compared to chickpea, faba bean, field pea, lentil, and soybean. The findings demonstrate that residual soil moisture can support post-season legume production in substantial parts of Ethiopia, particularly in wetter rainfed regions, while highlighting critical risks in moisture-limited environments. This study provides a spatially explicit framework to guide crop selection, planting strategies, and climate-resilient intensification of legume crops using residual soil moisture in rainfed agricultural systems.
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