Effect of three grazing intensities on selected soil properties in semi‐arid west Texas

Abstract

Soils in the study, carried out in the Texas Trans‐Pecos region, were fine‐loamy, mixed, thermic Aridic Calciustolls; fine‐loamy, mixed, thermic Aridic Ustochrepts; and fine, mixed, thermic Typic Chromusterts. Our primary objective was to determine the effect of three grazing intensities within an intensive, short‐duration grazing system on selected soil physical properties. Maximum compaction occurred in the A2/AB horizons, which has significantly higher (P<0.05) penetrometer readings than the overlying A I/A horizons under all grazing intensities. Heavily grazed areas also have significantly higher (P<0.05) penetrometer reading than the other two areas in both horizons. Heavily grazed areas also have significantly lower (P<0.05) infiltration rates, saturated hydraulic conductivities, and water‐stable aggregates than soils grazed at the other two levels. Aggregates in the A2/AB horizon were more stable than aggregates in the Al and Bw horizons in every pedon under all grazing intensities. When the effect of grazing intensity was analysed for each horizon separately, the lightly grazed areas had significantly lower (P<0.05) bulk density and higher total porosity in the A2/AB horizons than comparable horizons from the other two sites. However, when all horizons were analysed together, no significant differences in bulk density were found among treatments and horizons. No significant differences were observed in percentage organic carbon among treatments.

Additional keywords:

• Bulk density
• infiltration rates
• organic carbon
• short‐duration grazing
• soil compaction