TILLAGE AND RESIDUE EFFECTS ON INFILTRATION INTO SOILS CROPPED TO COTTON

Greater infiltration of precipitation increases water available for co tton (Gossypium hirsutum L.), wheat (Triticum aestivum L.), and sorghu m [Sorghum bicolor L. (Moench)] production on the semiarid Texas South Plains. The objective of this study was to determine the short-term e ffects of tillage and crop residues on water infiltration into an Olto n clay loam (fine, mixed, thermic Aridic Paleustoll), a Pullman clay l oam (fine, mixed, thermic Torrertic Paleustoll), and an Amarillo loamy fine sand (fine-loamy, mixed, thermic Aridic Paleustoll). Cropping tr eatments included (i) conventional tillage of continuous cotton (CVT), (ii) no-tillage, limited residue, of continuous cotton (C-NTL), and ( iii) no-tillage of cotton grown in rotation with limited grain sorghum (S-NTL), or (iv) wheat (W-NTL) residues. Final infiltration rate (IR) and cumulative infiltration (CI) was measured on three soils during t hree successive years after applying well water at 80 mm h-1 for 1 h w ith a rotating disk-type rainfall simulator. Cumulative infiltration v aried between 40 and 60 mm and did not increase with increasing sand c ontent among the three soils tested. Compared to CVT, neither W-NTL no r S-NTL resulted in significantly greater infiltration. Except on the Pullman soil, C-NTL consistently had the lowest CI; however, its infil tration tended to increase with time to a level similar to the other r otations of reduced till crops. Results shown that infiltration into t hese soils at mid-growing season was not affected by no-tillage manage ment of limited crop residues.