Effects of Land-Use Conversion on Water Runoff and Soil Erosion

摘要

Converting grassland on either 2.2 or 5.5 percent sloping loamy or 'hardland' soils in eastern Colorado to cropland in an alternate winter wheat-fallow rotation increased water runoff and soil erosion. The conversion increased water runoff from the 5.5 but not from the 2.2 percent slopes. The differences in plant population, presumably associated with soil temperature under different exposures, confounded the effect of slope on runoff. Average annual runoff over a 10-year period was 1.1 inches. Annual soil losses were correlated with runoff and were 5 times as great from cropland as from grassland on 5.5 percent slopes. Soil losses were 1.8 times as great from hallow as from wheat plots. On 2.2 percent slopes annual soil losses from cropland were 1.8 times the losses from grassland. However, the highest annual soil loss was only 2.7 tons per acre from the fallow plot on 5.5 percent slope.