Effects of Different Vegetation Measures on Soil Erosion in Olive Orchards in the Red Soil Region of Southern China

Taking four different slope vegetation measures ( Paspalum notatum + Oryza sativa, Chamaecrista rotundifolia + Stellaria media, Lespedeza bicolor + Ophiopogon japonicus, Gardenia jasminoides + Vetiveria zizanioides) and the bare slope of olive orchard as the research objects, this study conducted long-term positioning observation of soil erosion indicators in runoff plots and periodic determination of soil physical and chemical properties, to explore the differences in soil erosion degree and soil nutrients on the slopes of olive orchards in Minqing County under different vegetation measures. The results showed that: the Paspalum notatum + Oryza sativa treatment had the smallest average soil erosion amount and the lowest average runoff coefficient under erosive rainfall, which were superior to the bare slope and other vegetation measures; the overall soil infiltration characteristics followed the order of Chamaecrista rotundifolia + Stellaria media > Lespedeza bicolor + Ophiopogon japonicus > Paspalum notatum + Oryza sativa > Gardenia jasminoides + Vetiveria zizanioides > bare slope; in terms of soil physical and chemical properties, the Paspalum notatum + Oryza sativa treatment had the highest soil organic matter content, the lowest soil bulk density, and the highest total nitrogen and total potassium contents, while the Lespedeza bicolor + Ophiopogon japonicus treatment had the highest total phosphorus content; the comprehensive evaluation based on entropy weight method showed that the comprehensive anti-erosion index of the four vegetation measures followed the order of Paspalum notatum + Oryza sativa (0.9848) > Lespedeza bicolor + Ophiopogon japonicus (0.8085) > Gardenia jasminoides + Vetiveria zizanioides (0.6502) > Chamaecrista rotundifolia + Stellaria media (0.6291). In conclusion, the Paspalum notatum + Oryza sativa vegetation measure can effectively and rapidly reduce soil erosion on olive orchard slopes.