In the black soil area, where soil erosion is severe and the soil is in urgent need of ecological restoration, providing reasonable and practical measures to prevent soil erosion and restore the soil is an urgent issue at present. In this study, nine runoff plots were deployed in Bin County, the core area of soil erosion control, to monitor runoff and soil loss long-term, simulated by the erosion potential method (EPM) for comparison. Studies have shown that soil erosion is strongly influenced by soil conservation measures, land use, and vegetation cover. In contrast, slope, pre-soil moisture content, and soil crusting due to rainfall can affect erosion in a single rainfall event. The most severe soil erosion was in bare land, up to 1093.58 t km⁻² a⁻¹, followed by longitudinal ridge tillage land (751.88 t km⁻² a⁻¹) and cross ridge tillage land (31.58 t km⁻² a⁻¹). The shrublands and mixed forests planted for ecological restoration experienced almost no erosion. The soil loss rate of the cross ridge tillage and ecological restoration plots was much lower than the allowable soil loss rate (200 t km⁻² a⁻¹). Under erosive storms, longitudinal ridge tillage can produce soil loss rates that far exceed those of bare ground. The change from longitudinal ridge tillage to cross ridge tillage on gentle slopes can effectively prevent soil erosion in the study area. The vegetation restoration measures of planting shrubs such as Amorpha fruticosa Linn. are incredibly effective in the ecological restoration of wastelands in black soil areas. For the black soil area after the retreat, the vertical structure of vegetation can be improved by planting shrubs at the bottom, thus achieving a good restoration effect.

In order to identify the effects of the slope and precipitation intensity on the soil runoff depth and runoff rate, different tillage patterns (slope-ridge direction, horizontal slope-ridge direction, no-ridge farming) and different slopes (3° and 5°) were set up, and five typical rainfalls from June to September 2021 were selected, to dynamically monitor the soil-erosion dynamics of the test plots under different rainfall intensities. The results show that cross-slope-ridge cropping has a retention effect on runoff, which effectively inhibits the ineffective loss of rainfall confluence. Among these results, the variation range in the soil runoff depth under cross-slope-ridge treatment conditions was 0.11~0.94 mm, while that under the slope-ridge treatment and no-ridge treatment conditions was increased to 1.44~12.49 mm and 3.45~14.96 mm, respectively. It found that the loss of soil nutrients was significantly higher in the slope-ridge direction and in the no-ridge farming condition than in the horizontal slope-ridge direction. It is worth noting that, as the slope of the cultivated land increases, the erosive capacity of the precipitation runoff for the soil phosphorus increases, while the carrying capacity of the soil nitrogen decreases, and the correlation analysis results confirm that the corresponding relationship between the free diffusion capacity of the soil ammonium nitrogen and soil erosion is weaker than that between the nitrate nitrogen and soil erosion. The effects of single factors, such as the slope, ridge direction, and precipitation intensity of the cultivated land, have a significant impact on the soil water- and fertilizer-loss process, while the influence effect of the multi-factor coupling process on soil erosion is weakened. It was confirmed that the erosion process of rainfall runoff on soil nitrogen and phosphorus loss in slope cultivated land is the result of multi-factor action, and the artificial modification of the tillage mode can effectively regulate the effect of farmland water and fertilizer loss.

In recent years, China’s agricultural water consumption has been high, while water inefficiency has restricted the development of the economy. In this study, we developed an agricultural interval two-stage fuzzy differential water prices model (ITS-DWPM) by incorporating the techniques of two-stage programming (TP) and interval-parameter programming (IPP) based on the differential water price. The ITS-DWPM can link the associated economic penalty attributed to the violation of the preregulated water target and the total system benefit under limited data availabilities (expressed stochastic and interval values); meanwhile, inaccurate water quantity data and dynamic economic data would be resolved. The methodology tended to resolve the complexity of initial water rights allocation problems, incorporating the relevant sectors as well as the agricultural irrigation system construction involved in water management decision. Furthermore, the model takes into account the restrictions on water quantity and price. In addition, multiple decision results were calculated under different states of water shortage. The developed method is applied to initial water rights allocation and agricultural irrigation system construction. The results generated can assist decision makers not only in formulating water rights allocation strategies, but also in balancing the contradiction between economic objectives and water resources control indicators. In 2020, the irrigation water utilization coefficient of each agricultural irrigation area in Hulin City should reach 0.55. Hutou needs to increase its agricultural irrigation channels by at least 4.49%, Shitouhe by at least 4.03%, and Daxinancha by at least 4.49%.

In this study, an initial water-rights allocation (IWRA) model is proposed for adjusting the traditional initial water-rights empowerment model based on previous water intake permits, with the aim of improving the productivity of water resources under population growth and economic development. A stochastic scenario with Laplace criterion mixed fuzzy programming (SSLF) is developed into an IWRA model to deal with multiple uncertainties and complexities, which includes dynamic water demand, changing water policy, adjusted tradable water rights, the precise risk attitude of policymakers, development of the economy, and their interactions. SSLF not only deals with fuzziness in probability distributions with high satisfaction degrees, but also reflects the risk attitudes of policymakers with the Laplace criterion, which can handle the probability of scenario occurrence under the supposition of no data available. The developed IWRA model with the SSLF method is applied to a practical case in an alpine region of China. The results of adjusted initial water rights, optimal water-right allocation, changed industrial structure, and system benefits under various scenarios associated with risk attitudes and water productivity improvement were obtained and analyzed. It was found that the current initial water-rights allocation scheme based on previous intake water permits is not efficient, and this can be modified by the IWRA model. Based on the strategies of drinking safety and ecological security, the main tradeoff between agricultural and industrial water rights can facilitate optimization of the current initial water-rights allocation. This can assist policymakers in producing an effective plan to promote water productivity and water resource management in a robust and reliable manner.

Direct sewage discharge can cause severe damage to the water environment of the river. However, the impacts of dissolved organic matter (DOM) in the discharge on the original pattern of DOM and the distribution of heavy metals (HMs) in the river are little known. How to monitor such areas in a long-term and systematic manner also needs to be urgently addressed. In this paper, we characterized the DOM of the sediments in the WWTPs (wastewater treatment plants)-river integrated zone by ultraviolet-visible absorption spectroscopy (UV-vis), three-dimensional excitation-emission matrix (3D-EEM) combined with parallel factor (PARAFAC) method. The effects of WWTP on receiving waters were investigated, and the potential link between DOM and HM pollution was explored. Hg (I_geo: 3.94 ± 0.65; EF: 44.83 ± 31.11), Cd (I_geo: 1.81 ± 0.69; EF: 8.02 ± 2.97), Cu (I_geo: 1.61 ± 0.83; EF: 6.85 ± 2.37), Zn (I_geo: 1.55 ± 0.54; EF: 7.24 ± 3.58), and Ni (I_geo: 1.46 ± 0.56; EF: 6.12 ± 1.99) in rivers were the primary risk sources of HM. The combined pollution risk indicates that the WWTPs-river integrated area is in a high pollution risk state. Moreover, a(254) has a significant correlation with pollution indicators and can be used as a proxy indicator. These results help to understand better the impact of WWTPs on receiving water bodies and the potential connection between DOM and HM pollution and provide new ideas for monitoring the water environment in highly polluted areas.