Assessment of Soil Degradation Due to Compaction Resulting From Cattle Grazing Using Infiltration Parameters

The most essential effect of grazing is soil compaction due to animal traffic. The study was conducted to investigate the role of cattle grazing in soil degradation resulting from compaction using infiltration parameters at the Beef and Dairy Cattle Research Station of the Department of Animal Science of the Faculty of Agriculture, KNUST. Two fields, ungrazed and grazed (with a stocking rate of 120 cattle for three weeks) were used for the study. Physical properties such as soil texture, moisture content, bulk density, total porosity and aeration were determined. Field infiltration studies from which sorptivity (S) and steady state infiltrability (Ko) were determined were conducted with a double ring infiltrometer for one hour to determine the cumulative infiltration amount (I). The time-to-incipient ponding or runoff initiation time (tp) was calculated from the S and Ko values. Mean values of I were 1490 mm and 500 mm; S 2.72 mm/s 1/2 and 1.030 mm/s 1/2 ; Ko, 0.060 mm/s and 0.0080 mm/s for the ungrazed and grazed fields, respectively. The tp at a rainfall rate of 5 mm/h was recorded as 79.00 s on the grazed field and 419.00 s for the ungrazed field. It was observed that rainfall rates in excess of 10 mm/h would cause instantaneous ponding and/or runoff on both fields. Grazing by cattle was, thus, established to be deleterious to soil structure and infiltration due to soil compaction. Overall, infiltration parameters were found to be very useful tools for the evaluation of soil degradation due to compaction.