A field experiment was conducted to investigate the feasibility of making one measurement of soil moisture tension/content or crop water stress index (CWSI), and from it determine when and how much to irrigate. Cotton (Gossypium hirsutum C.V. DPL-90) was planted in a sandy loam soil prepared with an underground drip irrigation system. Measurements of soil moisture tension, soil moisture content, plant temperature, and wet- and dry-bulb temperatures were made. The results indicate that soil moisture tension above 0.30 m and soil moisture content about 0.50 m in the root zone can be used as good indicators for CWSI or vice versa. Further work is required using different irrigation systems and different crops in larger land areas. |