Effect of agroforestry and time on soil and water conservation of sloping red soil in southeastern China

Abstract

Soil and water loss from plots were recorded over five years (2001 to 2005) in an experiment comparing five different agricultural treatments on sloping red soil. Results showed that Bahia grass (Paspalum notatum Flugge) cover was an important factor for soil preservation, despite the presence of citrus tree planting or alley cropping in plots. The traditional rotation system (soybean [Glycine max L.]–radish [Raphanus sativus L.]) was shown to be unsuitable for soil and water conservation. However, changing crops should not be conducted during the period of high rainfall intensity. The effect of contour tillage was more significant than downslope tillage. Rainfall and rainfall erosivity did not differ significantly during the investigation period, whereas soil erosion decreased significantly over time. Planting citrus trees with Bahia grass cover generated the least runoff and sediment yield and showed a significant decreasing erosive trend with time. Thus, it proves to be an excellent choice for conserving soil and water resources on the red slopes of southeastern China.