Effect of Water Management and Surface Applied Barriers on Yield and Moisture Utilization of Grain Sorghum in the Southern Great Plains1

Abstract

AbstractThe effect of two irrigation schemes common to the High Plains and the effect of plastic film, asphalt film, and asphalt coated paper soil covers on grain sorghum (Sorghum vulgare Pers.) yield and soil moisture efficiency were examined. Early season results indicate that soil moisture losses are largely confined to soil evaporation and that these losses may predominate for approximately 3 weeks after planting. Conventional irrigation by physiological plant growth stages did not insure maximum yields. Maximum yields, maximum consumptive use, and minimum water use efficiency were obtained by maintaining the soil profile above 50% available moisture. With this high soil moisture condition, some consumptive use values for grain sorghum in the southern Great Plains exceeded 0.7 inch per day during mid‐summer. Exceptionally good yields, minimum consumptive use, and maximum water use efficiency were obtained by eliminating soil surface evaporation with a complete plastic film soil cover applied at planting. Partial soil surface covers of plastic film, asphalt film, and asphalt coated paper proved equally effective in reducing surface evaporation and increasing water use efficiency. Reduced yields were obtained from plots where the grain sorghum plants were allowed to show visual signs of moisture stress.