Effect of Dryland Leveling on Soil Moisture Storage and Grain Sorghum Yield

Abstract

D m o i s t u r e on nonirrigated land has caused researchers and others to seek ways to use precipitation more efficiently. One approach has been through land leveling to retain and uniformly distribute intense precipitation which would otherwise run off or collect in depressions*. Much of the dryland leveling in the United States has been concentrated in the Lower Rio Grande Valley of Texas where approximately 15,000 acres have been leveled during recent years. Although the benefits from this practice may appear obvious, certain essentials for success have been discussed by Robinsf. They are: (a) runoff must be appreciable and somewhat regular in occurrence, (b) runoff must occur when additional moisture can be stored and effectively used by crops, (c) soil moisture storage capacities must be high, and (d) suitable crops that can use the additional water must be grown. Field measurements of the ways in which various areas meet these essentials are limited. Hatchett and Marion ( 3 ) t at Spur, Texas, obtained increased cotton yields from benching 0.5 to 1 percent slopes during a two-yr period. However, Hauser and Cox (4) noted little or no benefit from bench leveling alone at Bushland, Texas. The study reported in this paper was initiated to determine the effect of leveling dryland areas on moisture storage and grain sorghum yield in the Lower Rio Grande Valley of Texas.