The effect of a moisture stress on soybean yield at various growth stages. From Shaw and Laing, 1966. Iowa State University. Availability of soil moisture Specific soil types have varying abilities to hold moisture. The available soil moisture, in terms of inches of water held per foot depth of a soil, is described in Table 2.
Sandy soils retain the least amount of water, while silt loam and clay loam soils hold the most.
Note that clay soils have less available water than do clay loam soils. Clay soils hold more water, but less of that water is available for plant growth because water adheres strongly to the clay particles. Potential available water storage capacity for various soil types. Adapted from Kiniry, Scrivner, and Keener, 1983. You must also consider the rooting depth of the crop in a particular soil.