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[Objective] With the intensified influence of climate change and human activities, the climate and underlying surface conditions of the basins have changed. Accurately simulating the process of soil moisture change and analyzing its influencing factors are of great significance for regional water resource management and vegetation construction. [Methods] The Weihe River Basin in the Loess Plateau was taken as the research object. Based on the ABCD hydrological model, the EFAST method was used to analyze the parameter sensitivity of the model, and the constant parameter and time-varying parameter models were constructed. The runoff depth and soil water storage simulation accuracy of different parameter models were compared. The effects of climate change and vegetation restoration on soil water storage changes in the Weihe River Basin were discussed, and the dominant factors of soil water storage changes were clarified. [Results] The proportional parameter of soil water layer recharge groundwater c was the most sensitive, followed by the groundwater storage coefficient d, the upper limit parameter b of the sum of actual evapotranspiration and soil water storage, and the tendency parameter a of runoff that before the soil is completely saturated was the least sensitive. Compared with the ABCD constant parameter model, the time-varying parameter model increased the values of NSE, KGE, and R2 of the runoff depth simulation results by 19%, 10%, and 19%, respectively, and the NSE, KGE, and R2 of the verification period increased by 7%, 7%, and 9%, respectively. The time-varying parameter model significantly improved the runoff depth simulation results. The srtongest correlation between soil water storage in the Weihe river basin and ERA 5-Land 0-100 cm soil layer based on time-varying parameter model simulation, and the change process of the two agreed well. The degree of different influencing factors on the change of soil water storage in the Weihe River Basin from strong to weak was potential evapotranspiration>precipitation>NDVI. [Conclusion] The research results provide a scientific basis for water resources planning and management and vegetation construction in this area and they also provide references for soil water storage research in other similar areas.

[Objective] The impacts on soil saturated hydraulic conductivity that occur because of differences in root and soil properties between combinations of grasses and shrubs having different root configurations were studied, and an empirical equation for estimating soil saturated hydraulic conductivity was established by comprehensively considering root and soil properties in order to provide a theoretical reference for the establishment of hydrological models appropriate for conditions following vegetation restoration on the Loess Plateau. [Methods] Plots of grass-shrub mixtures having different root system configurations were used: Agropyron cristatum and Caragana korshinskii, and Artemisia gmelinii and Caragana korshinskii. Saturated hydraulic conductivity was measured by the double-ring knife method. [Results] The influence of sample grass-shrub mixture type and soil depth on soil saturated hydraulic conductivity was significant, and their factor contribution rates on soil saturated hydraulic conductivity were 26% and 52%, respectively. The soil saturated hydraulic conductivity of the tap-root grass Artemisia gmelinii and Caragana korshinskii mixture was greater than that of the fibrous root grass Agropyron cristatum and Caragana korshinskii mixture. Soil saturated hydraulic conductivity of different plots declined with increasing soil depth. Root length density, soil aggregates, and soil bulk density better simulated soil saturated hydraulic conductivity, with a fitting accuracy (R2) reaching 0.86. [Conclusion] The combination of a taproot grass and a shrub had a higher saturated hydraulic conductivity than observed for the combination of fibrous root grasses and shrubs. Root length density, soil aggregates, and soil bulk density were the main factors affecting saturated hydraulic conductivity.

Northwest China is strategically crucial for China’s economic development, social stability, and national defense security. However, the shortage of water resources and its fragile ecological environment have been hindering local economic development and life quality improvement for local residents. In this study, we analyze the characteristics of agricultural production and trade in Northwest China from 2000 to 2018 from the perspective of water footprint and virtual water, and clarifies the impact of virtual water flow on local water resources. Research shows that the water footprint regarding crop production in Northwest China showed a fluctuating upward trend from 2000 to 2018. The outflow scale of virtual water gradually increases alongside with the transfer-out of fruits and cotton. The outflow of virtual water regarding fruits and cotton in Northwest China was 3.212 × 1011 m3 in 2018, accounting for 69.8 % of the total water footprint regarding crop production. The Yellow River Basin is the primary inflow area of virtual water from Northwest China, and the region northwest to the “Qice line” is the primary outflow area of virtual water. Water shortage is severe in Northwest China and fruit and cotton are planted for trade to drive economic growth. Therefore, optimizing the crop planting and virtual water trade structures and encouraging inter-basin water transfer are key measures to regulate physical–virtual water cycle, alleviate the contradiction between water supply and demand, and ensure regional water security.

Through field and laboratory tests we studied the temporal and spatial variation in the soil content of four available trace elements :copper(Cu), iron(Fe), manganese(Mn) and zinc (Zn), to analyze their distribution characteristics in reclaimed mining land under different reclamation conditions. The available trace elements content varied considerably with different land reclamation patterns. Extended reclamation time was helpful for the recovery of the available trace element content in the soil, and after more than eight years of soil reclamation, the content of available trace elements was closer to or greater than that in soil under natural conditions. Various treatment measures significantly influenced the content and distribution of available trace elements in the soil, and reasonable artificial treatments, including covering the soil and growing shrubs and herbaceous plants, increased the content of available trace elements.

In addition to greater precipitation on extreme days of precipitation, preceding and succeeding precipitation (PSP) is often an objective component of flooding in the mid–lower reaches of the Yangtze River Basin (MLRYRB). In this study, focused on the temporal distribution pattern of precipitation, the concept of an extreme precipitation event (EPE), defined as a consecutive precipitation event having at least one daily precipitation extreme, is proposed to consider PSP in an extreme event. We analyzed the spatiotemporal variation of four types of EPEs based on daily data obtained from 130 monitoring stations covering 1960–2019. Extreme precipitation increased significantly over the last 60 years (p < 0.01). The frequency and precipitation amount of single-day EPEs accounted for only 13% and 21%, respectively, while multi-day continuous EPE types that are associated with PSP accounted for 87% and 79%, respectively, confirming the connotations of EPEs. The front and late EPEs under the 100-year return level reached 250 mm and 230 mm, respectively. Furthermore, climate warming could lead to significant increases in the frequency of single-day and late EPEs, particularly in the southern region. The EPE concept may be helpful in exploring disaster-causing processes under extreme weather, and it provides a theoretical basis for deriving the precipitation hazard chain, which is more applicable to basins with long precipitation durations. [ABSTRACT FROM AUTHOR]

Abstract: In the context of the large-scale management of the Loess Plateau and efforts to reduce water and sediment in the Yellow River, this study focuses on a typical watershed within the Loess Plateau. The potential for vegetation restoration in the Kuye River Basin is estimated based on the assumption that vegetation cover should be relatively uniform under similar habitat conditions. The potential for terrace restoration is assessed through an analysis of topographic features and soil layer thickness, while the potential for silt dam construction is evaluated by considering various hydrological and geomorphological factors. Based on these assessments, the overall potential for soil erosion control in the watershed is synthesized, providing a comprehensive understanding of target areas for ecological restoration within the Kuye River Basin. The study demonstrates that the areas with the greatest potential for vegetation restoration in the Kuye River Basin are concentrated in the upper and middle reaches of the basin, which are in closer proximity to the river. The total potential for terracing is 1013.85 km2, which is primarily distributed across the river terraces, farmlands, and gentle slopes on both sides of the riverbanks. Additionally, the potential for the construction of check dams is 14,390 units. The target areas for terracing measures in the Kuye River Basin are primarily situated in the middle and lower reaches of the basin, which are in closer proximity to the river. Conversely, the target areas for forest, grass, and check dams, as well as other small watershed integrated management measures, are predominantly located in the hill and gully areas on the eastern and southern sides of the basin. The implementation of the gradual ecological construction of the watershed, based on the aforementioned objectives, will facilitate the protection, improvement, and rational utilization of soil, water, and other natural resources within the watershed. [ABSTRACT FROM AUTHOR]