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Reliable and accurate streamflow forecasting plays a vital role in the optimal management of water resources. To improve the stability and accuracy of streamflow forecasting, a hybrid decomposition-ensemble model named VMD-LSTM-GBRT, which is sensitive to sampling, noise and long historical changes of streamflow, was established. The variational mode decomposition (VMD) algorithm was first applied to extract features, which were then learned by several long short-term memory (LSTM) networks. Simultaneously, an ensemble tree, a gradient boosting tree for regression (GBRT), was trained to model the relationships between the extracted features and the original streamflow. The outputs of these LSTMs were finally reconstructed by the GBRT model to obtain the forecasting streamflow results. A historical daily streamflow series (from 1/1/1997 to 31/12/2014) for Yangxian station, Han River, China, was investigated by the proposed model. VMD-LSTM-GBRT was compared with respect to three aspects: (1) feature extraction algorithm; ensemble empirical mode decomposition (EEMD) was used. (2) Feature learning techniques; deep neural networks (DNNs) and support vector machines for regression (SVRs) were exploited. (3) Ensemble strategy; the summation strategy was used. The results indicate that the VMD-LSTM-GBRT model overwhelms all other peer models in terms of the root mean square error (RMSE = 36.3692), determination coefficient (R 2  = 0.9890), mean absolute error (MAE = 9.5246) and peak percentage threshold statistics (PPTS(5) = 0.0391%). The addressed approach based on the memory of long historical changes with deep feature representations had good stability and high prediction precision.

Hydraulic properties of sandy soil from the Mu Us sandy land of Shaanxi Province were analyzed by using SEM technology. Soil porosity, the water characteristic curve, and unsaturated hydraulic conductivity of aeolian sandy soil with added soft rock were analyzed, and fractal characteristics were established. Soil hydraulic properties revealed the effect of soft rock application on soil structure and hydraulic properties. Mass ratios of soft rock to aeolian sand were 1:5, 1:2, and 1:1. Results showed that the addition of soft rock can significantly increase the bulk density of sandy soil and reduce the total porosity and macroporosity. The mass fraction of water-stable aggregates greater than 0.25mm increases significantly, increasing the fractal dimension of soil pores; reducing the soil saturated water content and saturated hydraulic conductivity. SEM technology and pore fractal theory were used to predict the soil salinity curve and unsaturated hydraulic conductivity of the improved saline soil.

The organic carbon mineralization process reflects the release intensity of soil CO 2 . Therefore, the study of organic carbon mineralization and particle composition analysis of soft rock and sand compound soil can provide technical support and a theoretical basis for soil organic reconstruction (soil structure, materials and biological nutrition). Based on previous research, four treatments were selected: CK (soft rock:sand=0:1), C1 (soft rock:sand=1:5), C2 (soft rock:sand=1:2) and C3 (soft rock:sand=1:1), respectively. Specifically, we analyzed the organic carbon mineralization process and soil particle composition by lye absorption, laser granulometer, and scanning electron microscope. The results showed that there was no significant difference in organic carbon content between C1, C2 , and C3 treatments, but they were significantly higher than in the CK treatment ( P  < 0.05). The organic carbon mineralization rate in each treatment accords with a logarithmic function throughout the incubation period ( P  < 0.01), which can be divided into a rapid decline phase in days 1 to 11 followed by a steady decline phase in days 11 to 30. The cumulative mineralization on the 11th day reached 54.96%–74.44% of the total mineralization amount. At the end of the incubation, the cumulative mineralization and potential mineralizable organic carbon content of the C1, C2 and C3 treatments were significantly higher than those of the CK treatment. The cumulative mineralization rate was also the lowest in the C1 and C2 treatment. The turnover rate constant of soil organic carbon in each treatment was significantly lower than that of the CK treatment, and the residence time increased. With the increase of volume fraction of soft rock, the content of silt and clay particles increased gradually, the texture of soil changed from sandy soil to sandy loam, loam , and silty loam, respectively. With the increase of small particles, the structure of soil appear ed to collapse when the volume ratio of soft rock was 50%. A comprehensive mineralization index and scanning electron microscopy analysis, when the ratio of soft rock to sand volume was 1:5–1:2, this can effectively increase the accumulation of soil organic carbon. Then, the distribution of soil particles was more uniform, the soil structure was stable (not collapsed), and the mineralization level of unit organic carbon was lower. Our research results have practical significance for the large area popularization of soft rock and sand compound technology.

Electrokinetic remediation of saline soils currently faces two primary constraints: high energy consumption and considerable variability in the removal efficiency of salts and base ions under differing treatment conditions. These limitations have hindered the widespread practical adoption of this technology.This study explores the Ion removal effect by soil remediation and desalination. Through laboratory simulations, the base ion removal effects and energy consumption under various electric field conditions were investigated. The results show that electrokinetic remediation at 2.0 V/cm can effectively remove base ions from the soil, with notable removal efficiencies of Na+ and Cl-. It was also found that the electric field strength significantly affects both the remediation effect and energy consumption. An excessively high electric field strength may lead to a sharp decrease in soil moisture content, which in turn affects the remediation efficiency and increases energy consumption. Electrokinetic remediation has considerable potential for improving saline soils. By optimizing the electric field conditions and controlling pH levels, remediation can be enhanced while energy consumption is reduced. However, in practical applications, factors such as soil type and pollution degree must be considered, and further in-depth research is needed to refine and optimize remediation technology.

To investigate the effects of different types of land use and soil depths on the distributions of heavy metals in the soil in mining areas, heavy metals in different soil layers of five types of agricultural land in the Tongguan gold mining area were studied. The results revealed that the land use type had a greater impact than soil layers on the distribution of heavy metals in the soil. Among the five types of agricultural land examined, the risk values were only exceeded for the heavy metals lead(Pb) and mercury(Hg) in the pepper field, indicating combined pollution of Pb and Hg. Furthermore, some of the heavy metals, such as Pb, zinc(Zn), cadmium(Cd) and Hg, were highly significantly and positively correlated with each other. The pepper field should be monitored to prevent pollution from other heavy metals.

In view of the comprehensive problems of soil erosion and soil structural instability in the shoal land, in the process of remediation of Bailongjian in Huayin County, Shaanxi Province, the land reclamation and overburden were comprehensively designed using land leveling, river treatment and overburden comprehensive treatment techniques. Engineering, irrigation engineering, roads and shelterbelts; the implementation of the project model, the total rectification scale is about 67.94hm2, and the newly added cultivated land is about 61.93hm2. The utilization rate and output rate of land have been improved, agricultural production conditions and farmers' living environment have been improved. At the same time, it is of great significance to prevent soil erosion, continuously establish farmland ecosystems, and promote the improvement of comprehensive agricultural production capacity.

The effects of different combinations of three modifiers on the growth of beet on saline soil were studied. The results showed that the combination of calcium sulfate and ammonium sulfate in the four improved combinations of saline soil promoted the growth of beet. SPAD was 120.85% higher than the control group, the chlorophyll content was more than double that of the control group. The photosynthesis was strong, which played an important role in improving the quality of beet.

Based on CNKI data, this paper analyzes the number of papers, keywords and research content of biological soil crusts in the Mu Us Sandy Land. It was reviewed that the effects of biological soil crust on water infiltration, photosynthesis, respiration and succession characteristics and the influence of the technology of the compound soil of feldspathic sandstone and sand to create land on the development of biological crusts is considered in the Mu Us Sandy Land. The increase in clay content will significantly promote the expansion of sand biological crusts. At the same time, it is recommended to further carry out research on the development and succession characteristics of sand biological crusts after compounding of feldspathic sandstone and sand.

By analyzing the changes of calcium carbonate and free iron oxide in inorganic cement materials in different proportions of the feldspathic sandstone and sand compounding soil under different tillage years (2a and 9a), the calcium carbonate and free soil in the soil were determined in two years. The average content and relationship of iron oxide. The results show that the average content of calcium carbonate is the highest in the mixed soil of feldspathic sandstone and sand in the ratio of 1:2, the ratio is more favorable for the accumulation of calcium carbonate in 0-30cm soil surface inorganic colloid. The difference of organic carbon content in 0-10cm and 10-20cm soil layers was significant, but it was not significant in 20-30cm soil layers. After the mixture of feldspathic sandstone and sand for 9a, the highest content of organic carbon in each soil layer is the mixture of feldspathic sandstone and sand according to 1:1. From the mixture soil which has been cultivated for 9a, the soil layers of 10-20 cm and 20-30 cm, the content of organic carbon tends to be stable in each proportion. The average organic carbon content was 2.00 g/kg in 2a and 3.37 g/kg in 9a, which increased by 68.50% compared with 2a.

light has certain energy, so it can change the soil microstructure and the elements in the soil when it radiates the soil. In this paper, the changes of total nitrogen and organic carbon in the soil under white light were studied. The results showed that: the light had an activation effect on the organic carbon in the soil; the light exposed the organic matter in the soil, accelerated the decomposition of organic matter, and reduced the total content of organic carbon. The results show that the infrared light has no effect on the soil structure, and the ultraviolet light can change the soil structure.