Shallot Responses and Soil-Water Dynamics to Prolonged Water Stress Under Varying Soil Textures and Soil Amendment Applications

Water availability is essential for the growth of shallots. However, climate change and inadequate water management in agricultural fields often result in unavoidable water stress (drought), adversely affecting soil properties and plant development. Since soils with varying textures respond differently to drought conditions, this study aims to evaluate shallot growth across different soil textures and soil amendment applications, and to assess the responses of soil and plants under water stress. The study adopted a factorial randomized block design with two factors. The first factor was soil texture, consisting of sand, sandy loam, loam, silt loam, and clay. The second factor was the type of soil amendment, consisting of control (no soil amendment), guano, and rice husk. Each treatment combination was replicated three times, resulting in a total of 45 experimental units. The results indicated that shallots grew well in sandy loam, loam, silt loam, and clay soils when combined with soil amendments. Water stress affects soil temperature. Sandy soils show the highest daily and maximum temperatures but the lowest minimum temperatures. In contrast, silt, loam, and clay soils show higher minimum temperatures. Silt, loam, and clay soils exhibit the highest evapotranspiration rates, whereas the application of soil amendments across all soil textures reduces evapotranspiration. Evapotranspiration decreases further with increasing duration of water stress. Evapotranspiration determines the allowable depletion for shallots. Allowable depletion averages 20% in sandy soils, whereas in sandy loam, silt loam, and clay soils it exceeds 30%. These results provide important insights for water management in shallot cultivation across diverse soil conditions, enabling the achievement of optimal yields.