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Globally, water scarcity threatens food security, especially in arid and semi-arid food-producing regions, such as the Hetao Irrigation District (HID), where the water consumption during the non-growth season (spring irrigation, autumn irrigation) accounts for more than 30 % of the total irrigation volume. Meanwhile, mapping the characteristics of spatial and temporal evolution of the area of cropland irrigated in the spring and autumn and the pattern of water consumption is crucial for strengthening the management of agricultural water use. Evaporation and infiltration of irrigation water are difficult to capture in time due to insufficient timeliness or accuracy of single remote sensing data. This study integrates seven remote sensing datasets (Landsat5, Landsat7, Landsat8, HJ-1A/B, GF-1, Sentinel-2 and MODIS) for the first time to build a high spatial-temporal resolution dataset, and combines the water index NDWI and MNDWI to extract the maximum water range formed after irrigation by manually adjusting the threshold method. In addition to the global land use/cover dataset (GLC FCS30–1985_2020), the cropland layer was superimposed to accurately identify the cropland spring irrigation and autumn irrigation range from 2000 to 2021 in the HID. In the past 20 years, spring-irrigated (SI) areas increased by 1012.60 km2 (+49.96 %), and the autumn-irrigated (AI) areas decreased by 512.63 km2 (-11.02 %). Combined with the quantity of water diversion and displacement, the characteristics of irrigation water consumption in the non-growth season were further analysed. The results showed that the water consumption of spring irrigation increased by 0.67×108 m3 (+22.26 %), and that of autumn irrigation increased by 4.34×108 m3 (+38.82 %). The decrease of autumn- irrigated area and the increase of water consumption were mainly related to the stability of autumn irrigation water, imperfect irrigation and drainage conditions and insufficient field water management. In 2020­2021, the area of non-growth “autumn irrigation - spring irrigation” repeated irrigation is about 1271.52 km2, which can be used as a key control area. This study provides a theoretical basis and direction for rational water use in non-growth seasons of irrigation districts.

Technological advancements in isotope techniques have been widely utilized in environmental pollution research, particularly for the monitoring of nitrate pollution in water. The utilization of pretreatment with an aqueous nitric acid solution offers numerous advantages in analyzing isotopic composition; however, there is still room for improvement regarding conversion efficiency, reduced reaction time, and cost control. In light of this, this study proposes an enhanced chemical conversion method that involves mitigating the interference caused by the nitrogen azide reaction during the pretreatment process, optimizing the purge gas to remove interfering factors, and improving the inlet device for measuring nitrous oxide. The improved method was applied to determine nitrate isotopes in the Ulansuhai Basin, Inner Mongolia and its reliability was verified through analytical results obtained from bacterial denitrification methods. The mean δ15N-NO3- and δ18O-NO3- values determined using the chemical transformation method were 4.85‰ and 23.44‰, respectively. Compared with the previous method, the improved method enhanced the maneuverability of precise control, the pretreatment time was reduced from 2 to 3 hours to 1.5 hours, and the experimental cost was scaled down to half of the original one. In addition, the contribution of each source was calculated by combining nitrate isotopes with a Bayesian stable isotope mixing model. It was found that manure sewage accounted for (50.1±22.6) % while soil nitrogen sources contributed (25.1±20.4) % to nitrate levels in Ulansuhai Lake's water. The chemical conversion methods successfully improved within this study can also be applied to other watersheds or regions. These research findings provide a valuable theoretical foundation for managing nitrogen sources within watersheds.

This study investigated the effect of nitrogen application on the rhizosphere soil microenvironment of sunflower and clarified the relationship between ammonium assimilation and the microenvironment. In a field experiment high (HN, 190 kg/hm2), medium (MN, 120 kg/hm2) and low nitrogen (CK, 50 kg/hm2) treatments were made to replicate plots of sunflowers using drip irrigation. Metagenomic sequencing was used to analyze the community structure and functional genes involved in the ammonium assimilation pathway in rhizosphere soil. The findings indicated that glnA and gltB played a crucial role in the ammonium assimilation pathway in sunflower rhizosphere soil, with Actinobacteria and Proteobacteria being the primary contributors. Compared with CK treatment, the relative abundance of Actinobacteria increased by 15.57% under MN treatment, while the relative abundance decreased at flowering and maturation stages. Conversely, the relative abundance of Proteobacteria was 28.57 and 61.26% higher in the MN treatment during anthesis and maturation period, respectively, compared with the CK. Furthermore, during the bud stage and anthesis, the abundance of Actinobacteria, Proteobacteria, and their dominant species were influenced mainly by rhizosphere soil EC, ammonium nitrogen (NH4+-N), and nitrate nitrogen (NO3--N), whereas, at maturity, soil pH and NO3--N played a more significant role in shaping the community of ammonium-assimilating microorganisms. The MN treatment increased the root length density, surface area density, and root volume density of sunflower at the bud, flowering, and maturity stages compared to the CK. Moreover, root exudates such as oxalate and malate were positively correlated with the dominant species of Actinobacteria and Proteobacteria during anthesis and the maturation period. Under drip irrigation, applying 120 kg/hm2 of nitrogen to sunflowers effectively promoted the community structure of ammonium-assimilating microorganisms in rhizosphere soil and had a positive influence on the rhizosphere soil microenvironment and sunflower root growth.

Phosphorus (P) is a crucial nutrient in lake ecosystems and organic phosphorus (Po) is a significant component. However, the distribution characteristics and migration behaviour of Po in ice–water–sediment systems under freezing and thawing conditions in cold and arid regions remain unclear. This study aims to investigate the forms of Po and its contribution to endogenous P pollution. We selected three lakes (Dai, Hu, and Wu Lake) and employed phosphorus nuclear magnetic resonance (31P-NMR) techniques to analyse the following: (1) The total phosphorus (TP) content, which was the highest in the water from Dai Lake (0.16 mg/L), with substantial seasonal variation observed in Wu Lake, where P content was four times higher in summer than in winter because of farmland drainage. (2) Eutrophication analysis, which indicated that Dai Lake had significantly higher eutrophication levels than Wu Lake, with P being the controlling factor in Dai Lake and both N and P in Wu Lake. The proportion of Po in the TP content was 90%, 70%, and 55% for Wu, Dai, and Hu Lake, respectively, indicating that Po was the main component of eutrophic lakes. (3) 31P-NMR, which revealed that orthophosphate (Ortho-P) and monoester phosphate (Mon-P) were the main P components in the winter, with a higher P content in Dai Lake. Ortho-P has a higher content in ice, indicating that inorganic phosphorus (Pi) migration is the main factor in ice–water media. Mon-P showed multiple peaks in Dai Lake, indicating a complex composition of adenosine monophosphate and glucose-1-phosphate. (4) The ice–water phase change simulation experiments, which showed that phosphate was the least repelled in ice, while pyrophosphate (Pyro-P) and macromolecular P were more repelled. Adding sediment enhanced the migration of P but did not change the repulsion of macromolecular P, suggesting the molecular structure as the main influencing factor. These results provide important scientific evidence for the quantitative analysis of Po pollution in lake water environments, aiding in P load reduction and risk prevention and control.

Autumn irrigation is a key measure for alleviating soil salinity and promoting sustainable agricultural development in the Hetao Irrigation district; however, only a part of farmland is irrigated in autumn during the non-growth period of crops, which leads to the redistribution of soil water and salt between autumn-irrigated land (AIL) and adjacent non-autumn-irrigated land (NAIL) after autumn irrigation. To explore the distribution and variation of soil water and salt in different positions of AIL and NAIL after local autumn irrigation and reveal the interaction range between AIL and NAIL, field experiments were carried out for two years in typical test areas. The results showed that compared with non-autumn irrigation, autumn irrigation improved the distribution uniformity of soil water and salt profiles in both horizontal and vertical directions; after autumn irrigation, the water content of the soil at the nearest sampling point to the boundary in the AIL increased the least, but the desalination rate was the greatest, while the water and salt contents of the soil within 45 m from the sampling points to the boundary in the NAIL both increased significantly. NAIL received the drainage of AIL and made the groundwater level after the rise in AIL fell quickly back, but unreasonable autumn irrigation caused the groundwater level of AIL to remain at a high level before freezing, exacerbating the risk of groundwater carrying salts to the surface soil during the freezing and thawing period, detrimental to the growth of crops in the next spring. The research results are of great significance to the rational use of farmland water resources and the improvement of soil salinization in cold and dry areas.

The improvement of water usage efficiency and productivity, as well as the development of effective water management plans, necessitates a comprehensive understanding of how water utilization patterns in different soil layers within arid and semi-arid climates impact the capacity of plant roots to absorb water. However, there is currently no knowledge regarding the water use strategies employed by artificial yellow willow. So, we conducted a study on the hydrogen and oxygen isotopic composition of rainfall in yellow willow (Salix gordejevii) from the semi-arid region located at the southern edge of the Hunshandak Sandland in China. This study utilized measured data on xylem water, groundwater, soil moisture, and rainfall. By employing a combination of the direct comparison method and the MixSIAR model, we investigated the water uptake strategies employed by yellow willow throughout its growing season. The findings revealed that the mean δ D was highest in precipitation and lowest in groundwater, whereas the mean δ18O was highest in stem water and lowest in groundwater. The δ D and δ18O fluctuated significantly in precipitation but were steady in groundwater. Because precipitation was significantly less than evaporation, the slope and intercept were lower for the local than global atmospheric precipitation line. Water availability steadily declined with increasing depth. Lower δ18O values were caused by precipitation diluting the soil water. The MixSIAR results indicated that the primary source in May, September, and October was utilized at 19%, 18%, and 18%, respectively. In contrast, the utilization rate of each source varied considerably in June, July, and August (the primary source was utilized at 19%, 18%, and 18%, respectively). Comparatively high rates of water absorption and utilization were observed in June (19% of the total water source), July (18%), and August (23%). Therefore, the vertical distribution of the root system and variations in the soil water content regulate water usage for the yellow willow. To prevent excessive water usage and promote ecosystem restoration with artificial yellow willow plantations in water-limited desert settings, policy makers should consider the patterns of plant water use and soil water availability. By selecting drought-adapted plant species and optimizing irrigation management, it is possible to reduce water wastage and ensure that water is used efficiently for revegetation and ecosystem restoration, avoiding overuse of water and maintaining the sustainability of revegetation in water-stressed desert areas.

Given the low water and fertiliser use efficiency and the extensive distribution of sand interlayered soil in the Hetao irrigation district (HID), this study aimed to investigate the effects of different irrigation and fertilisation regimes on root parameters and yield in spring maize grown in sand interlayered soil. A two-year field plot experiment was conducted using the spring maize “Ximeng 3358” under three irrigation and nitrogen levels. Root length (RL), surface area (RS), diameter (RD), volume (RV), and length density (RLD), grain yield, and water use efficiency (WUE) were examined. Root growth was inhibited at the sand layer, with approximately 72.46–87.37% of the roots concentrated in the 0–40 cm soil layer. Notably, the proportion of roots in the bottom layer was 24.61–87.37% higher than that in the sub-bottom layer. Moreover, RL, RS, RD, and RV peaked in the medium irrigation and nitrogen fertilisation (I2F2) treatment. Furthermore, correlation analysis showed that the root parameters were significantly positively correlated with yield and WUE, with RS being most correlated to yield and WUE. Roots at a narrow row spacing of 20 cm (NR20) and at a depth of 10–20 cm were strongly correlated with yield and WUE. Conclusively, the I2F2 treatment can be used as the optimal combination of water and nitrogen for sand interlayered soil farmlands.

In order to achieve water conservation and salt control in saline irrigation areas and improve the soil ecological environment of farmland in irrigation areas, this study carried out a field trial in 2020–2021 on edible sunflowers planted in saline subsurface farmland in the Hetao Irrigation District. Three irrigation level treatments and a control setup under subsurface drainage were compared. The control was with no drainage and local conventional irrigation levels (the spring irrigation amount is 240 mm and the bud stage irrigation amount is 90 mm, CK); and the three irrigation levels were conventional irrigation (the spring irrigation amount is 240 mm and the bud stage irrigation amount is 90 mm, W1), medium water (the spring irrigation amount is 120 mm and the bud stage irrigation amount is 90 mm, W2), and low water (the spring irrigation amount is 120 mm and there is no irrigation in the bud stage, W3). The results showed that soil desalinization was best in the conventional irrigation (W1) treatment and lowest in the low-water treatment (W3) under subsurface drainage. The desalinization rate was 13.54% higher in the subsurface drainage than in the undrained treatment with the same amount of irrigation water. Under subsurface drainage, the medium-water treatment (W2) increased the diversity of soil microorganisms and the relative abundance of dominant phyla such as Ascomycetes, Chlorobacterium, Acidobacterium, and Ascomycetes among soil bacteria and Ascomycetes and Tephritobacterium amongst fungi. The average sunflower yield in the treatments under subsurface drainage increased by 32.37% compared with the undrained treatment, and the medium-water treatment (W2) was the most favorable for protein and essential amino acid synthesis. Structural equation modeling indicated that desalinization rate, irrigation water utilization efficiency, bacterial Chao1 abundance and Shannon diversity, and fungal Chao1 abundance and Shannon diversity were the major influences on sunflower yield. Based on the entropy weight method TOPSIS model, 15 indicators such as soil desalinization rate, soil microbial diversity, water and nitrogen utilization rate, and sunflower yield and quality were evaluated comprehensively for each water treatment of subsurface drainage farmland. It was found that the irrigation volume under tile drainage of 210 mm (W2) had the highest comprehensive score, which could improve the soil microenvironment of the farmland while realizing water conservation and salt control in salty farmland, increase the production of high-quality crops, and be conducive to the sustainable development of agriculture; it was the optimal irrigation treatment for the comprehensive effect. The results of this study are of great significance for the realization of efficient water conservation and salt control and the protection of food security and ecological safety in the Hetao Irrigation District.

In order to investigate the influence of freshwater fish ponds on water and salt transport in cultivated wasteland in salinized areas, a typical study area was selected in the middle and lower reaches of the Hetao Irrigation District in China in the Yichang Irrigation Domain, and the temporal and spatial changes in the salinity of soil and salinity of groundwater and fish pond water in the cultivated–wasteland–fish pond system were characterized through the monitoring of the environmental information of soil and groundwater at the boundaries of the cultivated land, wasteland, and fish ponds. Salinity changes and groundwater migration in different periods were determined, and the response of soil salinity to the depth of groundwater burial was analyzed, as well as the effect of fish ponds on soil salinization. The results showed that the amount of groundwater migrating from cropland to wasteland during the simulation period in 2022 was 2700 m3, the amount of groundwater migrating from wasteland to fish ponds was 630 m3, and the amount of groundwater migrating from fish ponds to wasteland during the fall watering period was 440 m3. From an overall perspective, the average soil salinity of wasteland was 1.56 times higher than that of the boundary of fish ponds. Not only do fish ponds play a positive role in the ecosystem, but they also have a desalinization effect that reduces soil salinity significantly. Groundwater depth and soil salinity have an exponential relationship; when the depth of groundwater is greater than 1.75 m, the soil salinity varies little with the depth of groundwater and the soil salinity is less than 0.66 ds/m, which can be determined as the critical depth, and the average depth of groundwater in cultivated land in the study area is 1.5 m. Therefore, it is necessary to reasonably control the water level of fish ponds, so as to make the groundwater depth of cultivated land control between 1.75 m and 2.0 m, and to prevent soil salinization.

Arthrospira platensis (A. platensis) is a species of cyanobacteria with high economic value; the species is commercially well known as Spirulina platensis, and A. platensis was used in this paper. Its high adaptability, high photosynthetic efficiency, and fast growth rate make it one of the few cyanobacteria that can be cultivated on a large scale. Therefore, using the selenium enrichment property of A. platensis to cultivate selenium-enriched A. platensis will not only enhance the physiological efficacy of A. platensis but also increase its economic value significantly. In this study, we investigated the effects of sodium selenite on the growth and photosynthetic performance of A. platensis selenium by setting different amounts and methods of sodium selenite addition, and we explored the optimal culture conditions of the best dosage and method of sodium selenite addition. The results showed that the experimental group treated with sodium selenite at 700 μmol/L had the fastest growth, and the contents of soluble protein, phycocyanin C, and chlorophyll a increased by approximately 67.9%, 1.44 times, and 38.8% compared to the control group, respectively. Superoxide dismutase (SOD) and catalase (CAT) activity increased by 1.88-fold and 65%, respectively, and malondialdehyde (MDA) levels were reduced by 62% compared to the control group. The results of the OJIP assay showed that the J and I points were significantly higher at the batch addition and treatment concentration of 700 μmol/L, with the rate of QA being reduced and the proportion of the slowly reduced PQ pool being increased. The values of the maximum light energy conversion efficiency (Fv/Fm) per unit of reaction center were higher in both sodium selenite treatment groups than in the control group, indicating that the light energy conversion efficiency of A. platensis was promoted under all concentration treatment conditions. The batch addition of sodium selenite at concentrations less than 700 μmol/L resulted in significantly higher ABS/RC values than the control, and they were far superior to the one-time addition method. The reason for this may have been that the batch addition of sodium selenite at low concentrations increased the light absorption capacity of the unit reaction center of PSII, resulting in a rise in captured light energy, a rise in the energy captured by the reaction center for electron transfer (ETo/RC), a decrease in the energy dissipated in the absorption of light energy by the reaction center (DIo/RC), and an increase in the photosynthetic performance index (PI abs).

Soil salinization affects more than 25% of land globally. Subsurface pipe drainage is known for its effectiveness in improving saline–alkali land. The red clay layer (RCL) hinders soil improvement in the Hetao Irrigation District of Inner Mongolia, China. The soil water and salt migration rules at different buried depths and RCL were studied based on the field subsurface pipe drainage test and simulation using the DRAINMOD-S model (Version 6.1). The following implications can be drawn from the results: (1) Although the RCL affected the accuracy of the model, the calibrated statistical results met the application requirements, and the DRAINMOD-S model can be used to analyze subsurface pipe drainage under different distribution conditions of the RCL. (2) The RCL can reduce the drainage efficiency of the subsurface pipe, specifically when the distribution is shallow. (3) The soil desalting rate increased with an increase in the buried depth of the subsurface pipe. The desalination effect of shallow soil was better than that of deep soil. The RCL reduced the drainage and salt removal efficiency of the subsurface pipe. Burying the subsurface pipe as far above the RCL as possible should be considered. Thus, it is feasible to apply the DRAINMOD-S model to relevant studies.

Controlling drainage during the growth stage is one of the means to provide suitable water and fertilizer conditions for crops, alleviate environmental pollution, and increase crop yield. Therefore, in this study, we studied three drainage treatments: free drainage (FD) and growth-stage subsurface controlled drainage (CD) at depths of 40 cm (CWT1) and 70 cm (CWT2). We used the HYDRUS-2D model to simulate the dynamic changes of NO3-N in the 0–100 cm soil layer as well as NO3-N uptake by crops, leaching after irrigation and fertilization, and loss through subsurface pipes in 2020 (model calibration period) and 2021 (model validation period). The degree of agreement between the simulated and measured values was high, indicating a high simulation accuracy. CD increased the soil NO3-N content and crop NO3-N uptake, and decreased NO3-N leaching and loss. We observed significant differences in the soil NO3-N content after irrigation at the budding stage of oilseed sunflower between CD and FD, with the largest difference seen for the 0–40 cm soil layer. CD increased crop yield, and the average oilseed sunflower yield of the CWT1 and CWT2 treatments increased by 4.52% and 3.04% relative to the FD treatment (p < 0.05). CD also enhanced nitrogen use efficiency. In moderately salinized soil, CD at 40 cm (CWT1) reduced the nutrient difference in vertical and horizontal directions while retaining water and fertilizer. CWT1 stabilized the groundwater depth, reduced the hydraulic gradient of groundwater runoff, and decreased the drainage flow rate. The NO3-N leaching and loss dropped, which promoted crop nitrogen uptake and utilization, improved nitrogen use efficiency, reduced nitrogen loss, and had a positive effect on protecting the soil and water environment. The results demonstrate that CD is a suitable drainage method for the experimental area.

The subsurface pipe drainage project is essential in farmland drainage operations and is globally recognized as an effective saline–alkali land improvement measure owing to its efficient drainage capacity and low land occupation rate. This study aimed to establish enhanced methods for improving saline–alkali land by combining ditching with subsurface pipe drainage. The ditching was conducted at a depth of 60 cm based on the existing subsurface pipe arrangement. The calibrated DRAINMOD-S model was employed to simulate the test area with different ditching depths and subsurface pipe arrangement parameters. Furthermore, the law of soil water and salt transport in the subsurface pipe drainage system at different ditching depths was investigated. After ditching, the total unit drainage volume of leaching increased by an average of 14.65% over two years and the water storage of different soil layers in the different plots decreased by 1.37–1.48 mm on average. Ditching demonstrated a superior salt-leaching effect in areas with subsurface pipe layouts. The soil desalination rate of different soil layers increased by 6.40–13.40% on average, with a more significant impact on the surface soil desalination rate. The effect of the increased desalination rate was more apparent as the ditching depth increased. However, as the buried depth of the subsurface pipe increased, the relationship between the ditching depth and soil desalination rate became insignificant. Ditching improved the salt-leaching effect of subsurface pipe drainage projects, which can effectively reduce the cost of subsurface pipe burial, consequently promoting subsurface pipe use.

Managing soil salinity has always been a difficult problem for agriculture. Balancing water and salt while maintaining crop quality and yield is a key issue for agricultural sustainability. The Hetao lrrigation District in China has a complex mix of cultivated and uncultivated land which plays a crucial role in soil salinization processes. To investigate the dynamic properties of soil moisture and salinity, soil ions and groundwater, cultivated and fallow soils in the Hetao lrrigation District were analyzed, side by side, using a combination of field and laboratory tests, with data processed using univariate and multivariate statistical approaches. The results showed that soil moisture increased with increasing soil depth in both cultivated and fallow soils. Salinity showed an increasing trend in 2022 and 2023 from April to September. The soil ions were mainly sulfate in the cultivated soils and chloride in the fallow soils. The characteristic factors affecting salt accumulation in cultivated soils are Na++K+, Cl−, SSC, SO42−, HCO3−, and pH, and the characteristic factors affecting salt accumulation in fallow soils are Na++K+, Cl−, SSC, HCO3−, and pH. Water table depth varied with irrigation and precipitation and was strongly influenced by external environmental factors. Groundwater salinity remained stable throughout the study period. This study provides a theoretical basis for the prevention and control of soil salinization in arid and semiarid areas through the “dry drainage salt” measure.

The introduction of contaminants of emerging concern (CECs) into the environment has raised concerns due to the significant risks they pose to both ecosystems and human health. In this sys-tematic review, we investigate research trends on CECs worldwide over the past 10 years, focus-ing on four critical aspects: (i) the identification and distribution of typical CECs across various media, (ii) the sources and environmental behavior of CECs, (iii) the implications of CECs expo-sure on human health, and (iv) risk assessment and control measures for CECs. The review re-veals a comprehensive understanding of the typical types and distribution of CECs in different environmental media, shedding light on their prevalence and potential impact on ecosystems. Furthermore, insights into the sources and behavior of CECs provide crucial information for de-vising effective strategies to mitigate their release into the environment. By examining the health effects of EC exposure, we highlight the importance of considering potential risks to human well-being. This aspect of the review emphasizes the significance of monitoring and managing CECs to safeguard public health. The review also synthesizes the advancements in risk assessment methodologies and control measures for CECs, which are essential for developing comprehensive regulations and guidelines to manage these contaminants effectively. Drawing from the findings, we identify future research directions for CECs in aquatic environments.

Abstract Background Inflammation plays a major role in the pulmonary artery hypertension (PAH) and the acute lung injury (ALI) diseases. The common feature of these complications is the dysfunction of pulmonary microvascular endothelial cells (PMVECs). Fasudil, the only Rho kinase (ROCK) inhibitor used in clinic, has been proved to be the most promising new drug for the treatment of PAH, with some anti-inflammatory activity. Therefore, in the present study, the effect of fasudil on lipopolysaccharide (LPS)-induced inflammatory injury in rat PMVECs was investigated. Methods LPS was used to make inflammatory injury model of rat PMVECs. Thereafter, the mRNA and protein expression of pro-inflammatory factors was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) assay respectively. Intracellular reactive oxygen species (ROS) levels were measured by the confocal laser scanning system. The activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the content of malondialdehyde (MDA) were determined by using commercial kits according to the manufacturer’s instructions. Western blot assay was used to detect the protein expression of nuclear factor kappa B (NF-κB) p65. Results Fasudil effectively prevented inflammatory injury induced by LPS, which is manifested by the decrease of pro-inflammatory cytokines interleukin-6 (IL-6) and monocyte chenotactic protein-1 (MCP-1). Meanwhile, fasudil dramatically reduced the levels of ROS and MDA, and also elevated the activities of SOD and GSH-Px. Furthermore, the nuclear translocation of NF-κB p65 induced by LPS was also suppressed by fasudil. Additionally, the ROS scavengers N-Acetylcysteine (N-Ace) was also found to inhibit the nuclear translocation of NF-κB and the mRNA expression of IL-6 and MCP-1 induced by LPS, which suggested that ROS was essential for the nuclear translocation of NF-κB. Conclusions The present study revealed that fasudil reduced the expression of inflammatory factors, alleviated the inflammatory and oxidative damage induced by LPS in rat PMVECs via ROS-NF-κB signaling pathway.

Soil salinization is a major factor impacting global crop yields. To explore the spatial distribution and influencing factors of soil water and salt in typical canals of the Hetao irrigation district, regional soil information was monitored at fixed locations. In this study, classical statistics, geostatistics, and spatial autocorrelation methods were used to conduct quantitative analyses of soil salt content, water content, soil particle size distribution, and groundwater depth. The variation coefficient of the soil salt content in the 20–40 and 40–60 cm soil layers was between 10% and 100%, which corresponds to a medium degree of variation; the other soil layers had strong degrees of variation. The soil moisture content in each layer varied moderately. The gold coefficients of soil salt content and water content were less than 0.25, and the Z value was greater than 0, showing a strong spatial correlation and certain spatial agglomeration characteristics, which were mainly affected by structural factors in the study area. The distribution patterns of soil water and salt were affected by soil particle size. Sand content decreased with increasing depth, soil salt was negatively correlated with sand content, and soil water was positively correlated with sand content. Soil salinity was significantly affected by groundwater depth and increased with decreasing groundwater depth, following an exponential relationship. When the groundwater depth exceeded 1.7 m, the soil salt content exhibited small changes with groundwater depth. The results of this study could play a guiding role in terms of understanding the degree of soil salinization surrounding canals in the Hetao irrigation area and adjusting land management strategies over time.

The Hetao Irrigation District is a typical salinized irrigation district in China, and soil salinization restricts agricultural development. To explore the spatial and temporal variability of soil water and salt and the coupling relationship in the Hetao Irrigation District, a field experiment was carried out at the scale of the Yichang Irrigation District branch canal in the downstream of the Hetao Irrigation District. Fifty-three soil sampling points were established to analyze the spatial and temporal variability of soil water content and total salt content and the coupling relationship using geostatistics and the coupling degree model. The results showed that soil water content in the study area belonged to medium variability and weak variability, and soil total salt content belonged to strong variability and medium variability. The theoretical models of soil water content and total salt content semi-variance function in the study area following the Gaussian model, with the block-base ratio less than 25%, with strong spatial autocorrelation, and the spatial correlation gradually increased with the increase of soil depth. The total salt content of the soil in the study area was interpolated with higher accuracy using radial basis functions as compared to ordinary kriging interpolation. In terms of temporal changes in salinity, the average salt accumulation rate of the 0–100 cm soil layer in the study area was 20.17% when salinity increased from May to June; the average desalination rate was 16.37% when salinity decreased from June to August. The main factors affecting soil salinity in cultivated land during the growing period were irrigation, precipitation, and planting crops, and the main factors affecting soil salinity in wasteland were precipitation and topography. The average coupling degree of soil water and salt in wasteland in the study area was lower than that of cultivated land, ranging from 65.15% to 86.59% of that of cultivated land. The level of coordination is marginal coordination for cultivated land and marginal disorder for wasteland. The study provides a theoretical basis for the prevention and control of soil salinization in arid areas.

As an effective method to improve saline–alkali land, the drainage from subsurface pipes has been extensively studied in typical arid and semi-arid agricultural areas (Hetao Irrigation District). However, there are few studies on the improvement of subsurface pipe layout and the long-term soil salinization control in the process of leaching and soil amendment with subsurface pipes in this area. This study investigated the water and salt migration in the process of amending the heavy saline soil. Field experiments growing sunflowers and numerical model calculation were combined in this research. It was found in the field experiment that the salt concentration in the surface pipe drainage was positively correlated with the salt content in the soil and the depth of the pipe, while it was negatively correlated with the amount of irrigation water and the spacing of crops. Thus, the soil desalting rate (N) and salt control rate (SCR) were positively correlated with the depth of the pipe, and they were negatively correlated with the spacing. The leaching effect of irrigation would decrease when the soil salt content decreased. On the basis of field experiments, the DRAINMOD model and drainmod equation were used to calculate the water and salt migration in 38 different field plots during 2019 and 2020. When N was the same, the soil salinity in several plots with large burial depth could be controlled below the salt tolerance threshold of sunflowers during the growth period in the second year. The quantitative relationship between N and SCR, soil salt content before leaching, water amount of leaching, pipe spacing and buried depth was already established. These results can help develop strategies for desalination and salt control in the soil in the arid and semi-arid areas with the optimal layout of subsurface pipes.

Biodegradable mulches have the same temperature- and moisture-preservation effects as ordinary plastic mulches before degradation. After degradation, rainwater enters the soil through the damaged parts, improving precipitation utilization. Under drip irrigation with mulching, this study explores precipitation utilization of biodegradable mulches under different precipitation intensities and the effects of different biodegradable mulches on the yield and water use efficiency (WUE) of spring maize in the West Liaohe Plain, China. In this paper, in situ field observation experiments were conducted for three consecutive years from 2016 to 2018. Three types of white degradable mulch films were set up, with induction periods of 60 d (WM60), 80 d (WM80), and 100 d (WM100). Three types of black degradable mulch films were also used, with induction periods of 60 d (BM60), 80 d (BM80), and 100 d (BM100). Precipitation utilization, yield, and WUE under biodegradable mulches were studied, with ordinary plastic mulches (PM) and bare land (CK) set as controls. The results showed that as precipitation increased, the effective infiltration of precipitation decreased first and then increased. When precipitation reached 89.21 mm, plastic film mulching no longer affected precipitation utilization. Under the same precipitation intensity, the precipitation effective infiltration ratio increased as the damage to the biodegradable film increased. Still, the intensity of this increase gradually decreased as the damage increased. The highest yield and WUE were observed for the degradable mulch film with an induction period of 60 days in years with normal rainfall and for the degradable mulch film with an induction period of 100 days in dry years. In the West Liaohe Plain, maize planted under film receives drip irrigation. We recommend that growers select a degradable mulch film with a degradation rate of 36.64% and an induction period of approximately 60 days in years with normal rainfall, and a degradable mulch film with an induction period of 100 days in dry years.

The impact of different combinations of water–nitrogen coupling on maize yield and the environment needs investigation. Low, medium, and high levels of irrigation and N application gradients were studied through field experiments to elucidate the suitable water–nitrogen coupling zone for spring maize in the West Liaohe Plain during three hydrological year patterns under drip irrigation with plastic film. The effects of different water–nitrogen couplings on maize yield, water- and nitrogen-use efficiencies (WUE and NUE), and post-harvest soil alkali-hydrolyzable N residues were studied under integrated drip irrigation by varying the application rates of water and fertilizer. A multi-objective optimization of water–nitrogen coupling zones was performed by integrating maize yield, harvest index, WUE, and soil environmental effects. Results show that with an increase in irrigation and N application rate, the residual amount of alkali-hydrolyzable N increased slowly within a certain range. Upon exceeding a certain amount, residual N increased rapidly, and more N entered the soil environment. The NUE of moderate water–nitrogen coupling treatment was high, with lower environmental risk of residual alkali-hydrolyzable N. Moderate irrigation yielded the highest harvest index in the normal hydrological year. Irrigation rate had a higher impact on yield compared to nitrogen application, because of drip irrigation under plastic film. An appropriate irrigation amount results in a higher WUE and the application of N application must be adjusted according to the rainfall in a particular year. This study highlights the need for structuring water–nitrogen coupling zones specifically for different hydrological years.

To investigate the contamination of PCBs in agricultural soils irrigated chronically with polluted water and the distribution and migration of PCBs under long-term irrigation, 100 farmland soil profile samples were collected in the Yellow River irrigation area in Inner Mongolia, China, to determine PCB content. Cluster analysis was used to identify possible sources of PCBs products, and the USEPA Health Risk Evaluation Model assessed the health risks posed by PCBs to humans. The results showed that the detection rates of eight monomers in the different soil layers of each sample site ranged from 5% to 90%, and the concentration ranged from not detected to 87.71 ng·g−1. The PCBs content showed a vertical distribution rule of accumulation in the shallow layer, sudden decrease in the middle layer. Low-chlorinated PCBs were dominant in each soil profile. Source identification indicated that PCB pollution in the study area originated mainly from the Aroclor1242, Aroclor1248, Aroclor1016, Aroclor1232, and Aroclor1221 industrial products and domestic transformer oil. Finally, a health risk assessment demonstrated that child and adult groups in study area were exposed to negligible carcinogenic and noncarcinogenic risks.

Desert oases are important parts of maintaining ecohydrology. However, irrigation water diverted from the Yellow River carries a large amount of salt into the desert oases in the Hetao plain. It is of the utmost importance to determine the characteristics of water and salt transport. Research was carried out in the Hetao plain of Inner Mongolia. Three methods, i.e., water-table fluctuation (WTF), soil hydrodynamics, and solute dynamics, were combined to build a water and salt balance model to reveal the relationship of water and salt transport in sand dune–wasteland–lake systems. Results showed that groundwater level had a typical seasonal-fluctuation pattern, and the groundwater transport direction in the sand dune–wasteland–lake system changed during different periods. During the crop-growth period (5 May–27 October), the average evapotranspiration values of the sand dune, wasteland–sand dune junction, and wasteland were 31–42% of the reference evapotranspiration. The water consumption of sand dune was 1.95 times that of the wasteland–sand dune junction, and 1.88 times that of wasteland. Water loss of the lake was 761.25–869.05 mm (5 May–27 October). The lake is facing the risk of drying up. The vertical salt transport of groundwater at the sand-dune site was 1.13 times that at the wasteland–sand dune junction site, and 1.82 times that at the wasteland site. Of the groundwater salt of the sand dune, 54% was accumulated in the groundwater of the wasteland–sand dune junction. Of the groundwater salt of the wasteland–sand dune junction, 53% was accumulated in wasteland groundwater, and the remaining 47% was accumulated in the lake. Salt storage of the 1 m soil layer of the sand dune was 85% that of the wasteland–sand dune junction, and 82% that of the wasteland. Research results provide a theoretical basis for the ecohydrology of the Hetao plain.

Green approaches are much more appreciable during the present scenario. Soil amendments are frequently applied for improving water use efficiency, reducing soil salinity in arid and semi-arid areas, controlling the secondary salinization of cultivated soils, and increasing the carbon sequestration capacity of soils. Thus, lab soil column simulation experiments and field experiments were carried out to evaluate these functions of two separate amendments, polyacrylamide-based super absorbent polymer (SAP) and corn straw biochar at different application rates. The simulation experiments showed that both SAP and biochar inhibited the accumulation of soil salinity, with a reduced rate of 9.7–26.3% and 13.5–37.2%, respectively, dependent on the amendment application rates. The field experiments found different salt inhibition effects of the two amendments with growth stages of maize. Soil salinization was inhibited in the pre-germination and early jointing stages by SAP, but throughout the whole growth period by biochar. Both soil amendments reduced soil electrical conductivity, and biochar increased the soil contents of Ca2+, Mg2+, and K+. Our observations demonstrated that application of biochar and SAP played important roles in increasing soil fertility and inhibiting soil salt accumulation. It provided an effective method to potentially mitigate the environmental crisis and promote sustainable development in agriculture.

Objectives: The aim of this study was to explore the pathogenic mechanism of group A Streptococcus (GAS) and to investigate how GAS evades phagocytosis by immune cells. Methods: The classical inflammatory signaling pathway of macrophages infected with GAS was investigated by protein microarray, real-time PCR, Western blot, immunoprecipitation, and flow cytometry. Results: GAS induced a lower level of inflammatory mediators in macrophages than either the Gram-positive Staphylococcus aureus or the Gram-negative Escherichia coli. Therefore, the conventional inflammatory signal pathway was investigated. It was found that GAS and S. aureus induced both toll-like receptor (TLR)2 and TLR4 expression, while Gram-negative E. coli only activated TLR4 in RAW264.7 cells. Although MyD88, the main adaptor protein, was activated by the three pathogens, there was no difference in MyD88 expression in macrophages. Nuclear factor kappa B (NF-κB) is the classical transcription factor of inflammatory signals, and the results of the present study showed that GAS, similar to E. coli, induced a weaker p65 nuclear translocation compared to S. aureus. Interestingly, GAS activated NF-κB by inducing p65–p52 heterodimer, but not the classical heterodimer of NF-κB (p65–p50), while E. coli activated NF-κB by inducing both p65–p50 and p65–p52 heterodimers. Conclusions: Compared to S. aureus and E. coli infection, GAS induced a weaker nuclear translocation and distinct combination of NF-κB subunits in macrophages, which probably leads to a weak inflammatory response.

The damages resulting from frost heaving are the main causes of channel destruction in seasonal frozen soil regions. Over the years, many experimental studies have been performed regarding the channel anti-frost heaving in the Hetao irrigation area. However, there have been few experimental research studies conducted regarding the insulation and anti-frost heave effects of polystyrene boards (EPS) of different thicknesses. Therefore, in order to explore the insulation mechanism and anti-frost heave effects of precast EPS laid under the conditions of different thicknesses, an anti-frost heave test field was established in the Hetao irrigation area for the examination of the ground temperatures, frozen depths, frost heave amounts, and water content change rules. This study’s results showed that, for the laid EPS with thicknesses between 2 and 12 cm, the frost-heave reduction rate ranged from 53.2% to 92.6%; total accumulated temperature warming ranged from 248.65% to 565.93%; and the frozen depth reduction rate was between 59.8% and 75.9%. It was determined that the EPS per cm additions could effectively improve the ground temperatures at a buried depth of 30 cm by 0.78 °C, and reduce the frozen depth by 10.1 cm. Then, by comprehensively considering the positive economic and insulation effects, it was determined that the most appropriate thickness of the EPS laid under the precast concrete slabs in the Hetao irrigation area of Inner Mongolia was 8–10 cm.

The sustainability of the Hetao Irrigation System, located in the water scarce upper Yellow River basin, is a priority considering the need for water saving, increased water productivity, and higher farmers’ incomes. The upgrading of basin irrigation, the main irrigation method, is essential and includes the adoption of precise land levelling, cut-off management, improved water distribution uniformity, and adequate irrigation scheduling. With this objective, the current study focuses on upgrading wheat basin irrigation through improved design using a decision support system (DSS) model, which considers land parcels characteristics, crop irrigation scheduling, soil infiltration, hydraulic simulation, and environmental and economic impacts. Its use includes outlining water saving scenarios and ranking alternative designs through multi-criteria analysis considering the priorities of stakeholders. The best alternatives concern flat level basins with a 100 and 200 m length and inflow rates between 2 and 4 L s−1 m−1. The total irrigation cost of designed projects, including the cost of the autumn irrigation, varies between 2400 and 3300 Yuan ha−1; the major cost component is land levelling, corresponding to 33–46% of total irrigation costs. The economic land productivity is about 18,000 Yuan ha−1. The DSS modelling defined guidelines to be applied by an extension service aimed at implementing better performing irrigation practices, and encouraged a good interaction between farmers and the Water Users Association, thus making easier the implementation of appropriate irrigation management programs.