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[Objective] This study explored the rainfall characteristics in loess hilly and gully regions and their impacts on runoff and sediment production on slopes of different land use types. [Method] From 2019 to 2021, runoff plots were set up in five different land use types including bare land, natural grassland, shrubland, farmland, and arbor land in the Hetonggou small watershed of Dalate Banner, Inner Mongolia. The rainfall characteristic indicators including rainfall, rainfall duration, maximum 30 minute rainfall intensity (I30), average rainfall intensity and rainfall erosivity were monitored. K-means clustering analysis was conducted using the rainfall characteristic indicators as variables to classify the erosive rainfalls. Then, the runoff depth and soil loss of different land use types in runoff plots were calculated, the impacts of different land use types and rainfall types on slope runoff and sediment production were analyzed, and the correlations of rainfall characteristics with total runoff depth and soil loss were evaluated. [Result] (1) From 2019 to 2021, the distribution of rainfalls in the Hetonggou small watershed was uneven, with a total of 128 rainfall occurrences, including 51 erosive rainfalls, accounting for 80.2% of the total.Erosive rainfalls were mainly concentrated from June to August. (2) Erosive rainfalls were divided into three categories of type I (heavy rainfall, long duration and high intensity), type II (moderate rainfall, moderate duration and moderate intensity) and type III (small rainfall, short duration and low intensity).Compared with type II and type III, type I rainfalls had a lower frequency of occurrence, but its average rainfall erosion was stronger. Under the same land use types, the depth of slope runoff and soil loss caused by type I rainfalls were significantly greater. (3) From 2019 to 2021, there were significant differences in the total runoff and sediment production characteristics of different land use types of runoff communities on slopes. The total runoff depth and total soil loss, in descending order, were bare land > farmland > natural grassland > shrubland > arbor land. (4) The various rainfall characteristic indicators were positively correlated with total runoff depth and total soil loss on slopes of different land use types. The main influencing factors were rainfall, rainfall intensity and I30. [Conclusion] In loess hilly and gully regions, rainfall, rainfall intensity and I30 were the main rainfall indicators affecting runoff and sediment production on slopes. Natural grasslands, arbor land and shrubland had better benefits from reducing runoff and sediment.Returning farmland to forests and grasslands on slopes was effective in reducing soil erosion. [ABSTRACT FROM AUTHOR]

[Objective] This study explored the effects of stand density of Caragana korshinskii plantation on species diversity and soil physical properties of herbaceous communities in sandy areas and determined the optimal stand density to provide references for better ecological service function. [Method] In Dalat Banner plantation of Ordos in the middle of Kubuqi Desert, Caragana korshinskii plantations with same site conditions, similar age and different stand densities were selected as the research objects. Woodlands with stand densities of 2 880-3 200 plants/hm² (I), 1 800-2 000 plants/hm² (II), 1 080-1 200 plants/hm² (III) and 720-800 plants/hm² (IV) were selected and compared with bare sandy land (CK). Species diversity of understory was characterized by herb community diversity.Height, cover and canopy width of plants in different stands were recorded.Soil water content, volume mass, field water capacity and total porosity were measured at soil layers of 0-20, 20-40, 40-60 and 60-80 cm by five-point sampling method.Correlations between plant community species diversity and soil physical properties were analyzed by redundancy analysis, and the principal components were used to evaluate Caragana korshinskii plantations. [Result] (1) There were 20 species of herbaceous plants, mainly Compositae.With the decrease of stand density, the Simpson, Shannon-Wiener and Margalef indices of herbaceous communities under Caragana korshinskii stand first increased and then decreased, and the order were in the order of III>IV>II> I>CK, while the Peilou evenness index showed no significant difference from CK. (2) Soil water content, total porosity and field water capacity of Caragana korshinskii plantation reached the peak values of 5.10%, 30.77% and 19.16% at density III.There was no significant difference in soil volume and mass among different plots (P>0.05). There were significant differences in soil moisture content between 0-40 cm and 40-80 cm soil layers (P<0.05).With the deepening of soil layer, volume quality of soil increased. (3) There were certain correlations between species diversity indices and soil physical properties in each density plot. (4) Comprehensive evaluation showed that plantations were in the order of III (2.276) > IV (1.261) > II (0.294) > I (-0.815) > CK (-3.017). [Conclusion] 1 080-1 200 plants/hm² was the appropriate density for the restoration of vegetation and soil physical properties of Caragana korshinskii plantation in the study area. [ABSTRACT FROM AUTHOR]