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To effectively control nonpoint source pollution and predict its transport and load, understanding water and solute transport processes, patterns and mechanisms is essential. However, the measurement of water movement and solute transport parameters is usually a laborious and time‐consuming task. It is important to predict water movement and solute transport parameters from more readily available soil physical and chemical properties. In this study, a database of soil hydraulic and solute transport parameters containing information retrieved from 83 published studies on soil properties, land use, management measures, etc. was established to characterize and simulate soil water movement and solute transport processes. Our results showed that the soil particle composition was closely related to all soil hydraulic and solute transport parameters. As the soil texture changed from sand to clay, the soil residual water content (θr) obviously increased. The soil porosity was significantly positively correlated with θr, saturated water content (θs), van Genuchten parameter α, dispersity (λ) and retardation factor (R) and negatively correlated with van Genuchten parameter n (p < 0.01). The use of random forest models allowed the prediction of soil hydraulic and solute transport parameters by inputting common or even incomplete soil property parameters. The bulk density and particle composition jointly contributed 66% to the prediction of the soil hydraulic parameters and 44% to the prediction of the solute transport parameters. The pH exerted a notable impact on the solute transport parameters, especially dispersion coefficient (D), λ and R. The results may be useful in providing data support and facilitating the development of watershed nonpoint source pollution models. [ABSTRACT FROM AUTHOR]

After decades of comprehensive management, the hydrology and sediment dynamics of the middle Yellow River Basin have changed significantly. However, the comprehensive evaluation of the water and sediment regimes and its potential attribution at the regional scale are limited. In this study, the hydrological characteristics and in‐reach sediment budget in the Coarse Sandy Hilly Catchments (CSHC) region and their potential attribution were investigated by using data from hydrological stations in the mainstream and tributaries and data from soil and water conservation measures (SWCMs) in different river reaches. The results indicated that the runoff and sediment load of the mainstream showed obvious spatial heterogeneity, both of which revealed a very significant decreasing trend from 1956 to 2018 (P < 0.01). The spatial heterogeneity of sediment load along the mainstream was more obvious than that of streamflow, and the Toudaoguai and Fugu stations had the largest difference in sediment transport trends. During the P1 period (1956‑1968), the streamflow of each reach was sufficient, and the riverbeds of the mainstream and channel on both banks were subject to serious scouring. In the P2‑P3 period (1969‑2018), in‐reach water decreased continuously, and the mainstream began to show a process from slight scouring to no scouring and even sediment deposition. Except for climate change being the main factor in streamflow reduction during the P2 period (1969‑1999) at the Fugu and Wubao stations, anthropogenic activities were the primary factors leading to the reduction in streamflow and sediment load in the CSHC region. Under the influence of the same measures, the sediment reduction rate in this region was greater than the runoff reduction rate. Furthermore, the SWCMs in different reaches indicated great diversity in the benefits of water and sediment reduction. Therefore, zoning regulation of the CSHC region should be carried out in the future, and the sustainable development of the regional vegetation ecosystem should be maintained. [ABSTRACT FROM AUTHOR]