Soil–water retention characteristics and plant‐available water (PAW) are critical for irrigation management in semiarid Andosols. This study determined the soil–water characteristic curves (SWCCs) of Andosols at the Melkassa Agricultural Research Center (MARC), Central Rift Valley (CRV), Ethiopia, using a pressure plate apparatus at matric potentials of 33, 500, 1000, and 1500 kPa. Soil samples ( n = 60) were collected from five fields (K, D1, A2, Avocado, and Abaderash) at depths of 0–30, 30–60, 60–90, and 90–120 cm, with textures classified as clay loam, loam, and sandy loam. Bulk density ranged from 1.11 to 1.39 g·cm −3 . Field capacity (FC) varied from 21.24% (sandy loam, A2 90–120 cm) to 32.78% (loam, K 90–120 cm), permanent wilting point (PWP) from ∼14 to 24%, and total available water (TAW) from 6.30% (D1 0–30 cm) to 15.49% (A2 60–90 cm loam). Averaged by texture, loam showed the highest FC (29.89%), PWP (19.36%), and TAW (10.16%), followed by sandy loam (TAW 9.50%) and clay loam (TAW 8.88%). SWCCs indicated loam’s optimal pore distribution for PAW, with clay loam retaining more unavailable micropore water and sandy loam draining rapidly. Chemical properties (pH 7.20–8.19, EC 151–399 µS·cm −1 , OC 0.28%–1.48%, TN 0.03%–0.14%) declined with depth. Correlation analysis showed that TAW was positively correlated with depth and sand ( r = 0.87–0.96) and negatively correlated with organic carbon (OC) and clay ( r = −0.91–−0.96). Spatial and depth variability underscores site‐specific irrigation: loam‐rich subsoils (e.g., A2) suit water‐demanding crops with longer intervals, whereas low‐TAW sites (e.g., D1) require frequent applications. SWCC‐informed strategies enhance water‐use efficiency and sustainability in semiarid Andosols.
Aregahegn et al. (Thu,) studied this question.