Rainwater interception by leaf litter is an important part of forest hydrological processes. The objective of this study was to investigate the interception storage capacity (ISC) of woodland leaf litter for three leaf distribution patterns, one flow path, two flow paths, and three flow paths, manually simulated via one-by-one leaf connection in the top leaf litter layer. A random pattern served as the control. Three different slopes (0 , 5 and 25 , representing flat, gentle and steep slopes, respectively) and two contrasting leaf litters (needle-leaf litter, represented by P. massoniana leaves, and broad-leaf litter, represented by C. camphora leaves) with a biomass of 0.5 kg/m 2 per unit area were applied, at a rainfall intensity of 50 mm/h. Results suggested that leaf distribution pattern greatly impacts litter drainage and hence affects leaf litter ISC. The delaying capacity of litter drainage initiation and ISC of broad-leaf litter were higher than those of needle-leaf litter under the same slope conditions. The maximum ISC (C max) and minimum ISC (C min) of leaf litter at flat and gentle slopes were higher than those at steep slope. C min of the broad-leaf litter was two times higher than that of needle-leaf litter on average. When raindrops reached the litter layer, some were temporarily intercepted by the top litter layer while others infiltrated leaf litter sublayer along leaf edges, and in the process, some rainwater flowed through litter layer and contributed to lateral litter drainage along the potential flow path formed by leaves. The lateral litter drainage of broad-leaf litter was higher than that of needle-leaf litter, and the partitioning of rainwater into lateral litter drainage increased with increases in slope. The difference in leaf litter C max among different slopes and leaf shapes decreased with flow path increasing. Therefore, leaf distribution pattern notably impact leaf litter ISC, which is similar to leaf shape and slope impacts. On inclined slopes, avoiding leaf accumulation to form flow path is helpful for improving ISC.

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The soil and water conservation ratio (SWCR), which is a quantitative index for measuring the control degree of soil and water loss, is equal to the percentage of the land areas with a slight erosion intensity in the study area. The dynamic change in the SWCR reflects the dynamic process of realizing a specific soil and water conservation goal in a certain stage. The objectives of this study were to evaluate the change in the SWCR in the Guizhou Province in this century and to analyze its causes. The temporal and spatial variations of soil erosion intensity and SWCR were measured based on GIS technology and revised universal soil loss equation (RUSLE). The results showed that the spatial pattern of soil erosion intensity in the Guizhou Province was high in the west and low in the southeast, and that the soil erosion characteristics were obviously different between karst and non-karst areas. In the karst areas, the land with a moderate and above erosion intensity (>3 t hm−2 y−1 in the karst area; >25 t hm−2 y−1 in the non-karst area) accounted for 28.20–34.78% of the total area, while only accounting for 2.39–2.72% in the non-karst areas. From 2000 to 2019, the mean intensity of soil erosion decreased from 13.97 to 10.83 t hm−2 y−1, and the SWCR increased from 32.95% to 35.31%. According to the change in erosion intensity grades, 22.30% of the whole province’s erosion grade changed from high to low, especially in the west, with a high erosion intensity. Meanwhile, about 11.99% of the land in the central, eastern and southeastern regions, was where the erosion intensity showed a slight increase and the spatial distribution showed sporadic patch distribution characteristics, which may be related to an increase in infrastructure investment in the Guizhou Province in recent years. A large number of production and construction projects caused the destruction of surface vegetation and also caused patchy soil erosion. The spatial and temporal characteristics of the soil erosion and the SWCR in the Guizhou Province between 2000 and 2019 were mastered through this study, and our results provide an important basis for further scientific and reasonable soil and water conservation planning work.

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