Objective In order to provide the basis for the optimal allocation of vegetation patterns for soil and water conservation in the Loess Plateau and other water resource deficient areas, the effects of different vegetation patterns and fragmentation on runoff and sediment yield were studied.
Method To explore the impacts of different vegetation patterns on runoff, sediment, and infiltration in this research, we measured the characteristics of runoff, sediment, and soil infiltration of five vegetation patterns (block-shaped mosaic pattern plots SP1, SP2, horizontal strip pattern plot BP, slope band pattern plot LP, and bare land pattern plot CK, respectively) by field simulated rainfall tests.
Result (1) In general, vegetation had relatively good capacity in sediment reduction and water storage. The sediment reduction efficiency reached 47.44%−91.67%, and the water storage efficiency reached 25.67%−62.94%. Therefore, the sediment reduction capacity of vegetation was stronger than the water storage capacity. (2) The vegetation patterns had statistically significant effects on the runoff and sediment yield on the slope (P < 0.05). The order of the highest to lowest storage and sediment reduction effects of vegetation patterns were block-shaped mosaic pattern, horizontal strip pattern, followed by the slope band pattern. Thus, the block-shaped mosaic pattern had the best soil and water conservation effect. (3) The process for the runoff occurrence of different vegetation patterns showed a trend of “a rapid-rise phase followed by a relative stable phase”. The vegetation patterns helped to delay the occurrence of the runoff peaks. (4) The fragmentation index of vegetation patches was inversely proportional to the erosion and sediment production. The higher the degree of fragmentation of vegetation patches was, the lower the sediment yield and the better the efficiency of water storage and sediment reduction were. (5) The infiltration coefficient of different vegetation patterns was in the following order: the block-shaped mosaic pattern > horizontal strip pattern > slope band pattern > bare land pattern. Further, the Horton model exhibited a good fitting behavior on soil infiltration of different vegetation patterns.
Conclusion Through the above research, it is found that vegetation and bare land mosaic pattern are significantly better than that of bare land and long strip slope pattern in water storage and sediment reduction. Therefore, in the loess area with limited water resources, vegetation can be planted in the way of alternate distribution of vegetation and bare land to maximize the benefits of water storage and sediment reduction.
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