Effect of Long Time Erosion on the Propertiesof Loamy Sand Soils of the Bridgnorth SeriesCompared

The properties of loamy sand soils of the Bridgnorth series were investigated after being bare for 12 years on runoff plots and compared with adjacent grassland at the Hilton experimental site, east Shropshire, UK Soil organic matter and most nutrients (Al2O3, Ca2O, MnO, Na2O, P2O5, SiO2 and Cu) were significantly lower in bare soil than in grassland soil Include mean values soil organic matter was 215 times higher in grassland than in bare soil, with highest values on the bottom of the slope on both bare and grassed plots The grassland soil contained relatively higher coarse sand (0355-20 mm), particularly 05～10 mm fraction, and less clay (<0002 mm) and coarse (>2 mm) fractions than bare soil This suggests that the coarse sand was selectively removed by erosion; the loamy sands tend to decrease coarse sand and increase clay content after prolonged erosion The results indicated that clay and silt tend to be transported down slope Significant positive linear relationships between clay, fine silt and slope, and a significant negative linear relationship between sand and slope were found in grassland soil Furthermore, there was a trend for soil pH to be less on bare soil Results suggest that the soil fertility decreases quickly if soil is exposed for long periods and no organic matter or fertilizer is applied; conversely grass may maintain and improve soil productivity. Results also indicate that hill slope cultivation and erosion caused the topsoil, nutrients and organic matter to accumulate down slope.