RESIDUE MANAGEMENT EFFECTS ON INFILTRATION INTO SEMI-ARID DRYLANDS

Sustainable dryland production systems rely on effective methods of storing soil water for later use by crops. Residue-retaining conservation tillage systems first developed on the southern Great Plains for wind erosion control also have the added benefit of increasing the amount of precipitation stored as soil water. Residue in these conservation tillage systems intercepts raindrop impact, which reduces soil crust formation and surface compaction. Consequently, infiltration is greater and precipitation storage in the soil increased; however, in semiarid regions, dryland crops produce limited residue amounts that can render these residue management practices ineffective. This paper reviews and contrast studies characterizing residue effects on rain infiltration and annual storm runoff measured at Bushland and Lubbock, TX. DRYLAND CROPPING SYSTEMS This paper reviews research characterizing conservation tillage effects on rain infiltration and storm-water runoff. The High Plains portion of the southern Great Plains is at an elevation>3300 ft (1000 m) above mean sea level and has a semiarid continental climate characterized by high winds that promote evaporation. While pan evaporation over much of the region ranges from about 70 – 100 inches (1800 – 2500 mm) per year, precipitation (rain) is erratic in bot