To explore the appropriate irrigation water salinity for normal emergence, high yield, good quality of maize, as well as limited soil salt accumulation in arid and semi-arid agricultural areas of northern China, a two-year field experiment of maize mulched drip irrigation was carried out in Hetao Irrigation District of Inner Mongolia. The experiment involved five irrigation water salinity levels (1, 2, 3, 4, and 5 g/L). Under the conditions with soil matric potential lower limit of -20 kPa and irrigation quota of 22.5 mm per application, the water consumption, plant dry matter accumulation and grain yield of maize had significant quadratic function relationship with the irrigation water salinity (R ²>0.84). When the irrigation water salt content was 2 g/L, the plant dry matter accumulation and grain yield reached the maximum value. However, as the irrigation water salinity exceeded 3 g/L, saline water irrigation showed adverse effects on the emergence rate, dry matter accumulation and grain yield of maize. When the irrigation water salinity increased by 1 g/L within the range of 1~5 g/L, the water use efficiency decreased by 0.29 kg/m³. The grain protein content increased with the increase of irrigation water salinity, while the grain starch content decreased with the increase of irrigation water salinity. In addition, when the irrigation water salinity exceeded 3 g/L, the vertical radius and horizontal radius of soil salinity contour corresponding to mulched drip irrigation decreased with the increase of irrigation water salinity. Based on the goal of achieving high grain yield, good maize quality and reducing soil salt accumulation during the maize growth period, the upper limit of irrigation water salinity for maize mulched drip irrigation in Hetao Irrigation District is recommended to be 3 g/L considering the conditions of the present experiment design.

Artificial groundwater recharge is a vital method for aquifer management and water resource storage. Exploring a rational suitability evaluation method is fundamental in identifying recharge areas. Utilizing remote sensing data and Geographic Information System (GIS) technology, a GIS-IFAHP decision model was constructed in this study using the intuitive fuzzy analytic hierarchy process (IFAHP). Eight indicators, namely, groundwater level, degree of water supply, soil texture, aquifer permeability coefficient, terrain slope, land use/cover, distance to irrigation areas, and river network density were selected for subjective hierarchical ranking to obtain the synthetic subjective weight of each indicator. The weighted superposition analysis method was employed to generate a suitability zoning map for artificial groundwater recharge in the study area. Furthermore, surface infiltration tests were conducted in high-suitability zones to analyze the feasibility of groundwater recharge. The results of this study are as follows: Low-suitability zones for groundwater recharge were mainly found in fine-soil plain areas, accounting for approximately 13.24% of the total recharge area. Moderate-suitability zones were primarily situated in the middle and lower sections of the gravelly plains, occupying 29.48% of the recharge area. High-suitability zones were predominantly located in the middle and upper sections of the gravelly plains, comprising 18.94% of the total recharge area. Within a duration of 8 days, a total of 1.54×10⁴ m³ of water was successfully recharged into the surface seepage reservoir. Throughout the recharge period, the water levels in the three observation holes stabilized at 14.95 m on average, resulting in an average cumulative rise of the groundwater level by 25.21 m. The GIS-IFAHP decision model demonstrated excellent performance in rationalizing the selection of groundwater recharge areas. In arid regions, groundwater could be effectively recharged for inclined gravelly plains with low land use and favorable recharge conditions through the mechanism of surface infiltration.

To investigate the impact of spring irrigation quotas on the distribution of soil water and salt in farmland with varying salinity levels, and determine the suitable spring irrigation quotas for soil moisture preservation and salt washing, three types of spring irrigation quotas treatments (W1:1 800 m³/hm², W2:2 250 m³/hm², W3:2 700 m³/hm²) were implemented in moderate saline alkali land S1 (5.23 g/kg) and severe saline alkali land S2 (8.27 g/kg), respectively. The water and salt transport and distribution in soil layers of 0~100 cm from spring irrigation to cotton sowing were analyzed and compared. The results showed that from 14 to 21 days after spring irrigation, 71.37% of the water content in S1W2 treatment can be maintained in the soil, while 77.26% of the water content in S2W3 treatment can be maintained in the soil, which can achieve suitable soil moisture for crop growth in farmland soil. Salt leaching mainly occurs in the 0~60 cm soil layer, and the leaching effect is more significant within 0~30 cm. Greater spring irrigation quotas resulted in a stronger salt accumulation in deeper soil layers The phenomenon of salt return begins to appear 21 days after spring irrigation. The spring irrigation time should be around 21 days before sowing. When the spring irrigation quotas for moderately saline alkali soil is 2 284.7 m³/hm² and for heavily saline alkali soil is around 2 700 m³/hm², it can achieve a relatively good water-saving, moisture retention, and salt washing effect. For heavily saline alkali soil, the spring irrigation quota can be appropriately increased based on the actual situation. The research results can provide a certain theoretical basis and technical reference for spring irrigation in farmland with different salinity and alkalinity in Tumushuke City.

Farmland ditch is an important infrastructure for farmland, and a wide variety of agricultural drainage ditches can undertake functions such as protecting and nurturing frogs and other animals, purifying water quality, removing pollutants, and protecting ecology. The evaluation of farmland drainage ditches is an important support for guiding ditch construction. However, there is a lack of comprehensive reports on the evaluation of farmland ditches, particularly regarding the systematic evaluation using the concepts and dimensions of ecological restoration, which requires further investigation and discussion. This article uses the Analytic Hierarchy Process to conduct empirical research on the factors affecting the ecological restoration of farmland and canals in Shanghai. Nine experts were invited to rank the weights of six key influencing factors for the ecological restoration of farmland and canals. The results show that physical conditions>threat exemption>structural diversity>species composition>ecosystem function>external exchange relationship. This study provides a new perspective and method for the study of ecological environment issues in farmland ditche, and the established evaluation model can assess the effectiveness of ecological environment restoration in farmland ditche.

The agricultural planting system in Xinjiang commonly employs the drip irrigation with low discharge during the growth period to improve the water use efficiency, and then applies furrow irrigation at fallow period to restrict the secondary salinization. However, this relatively complex process increases the input of labor and material resources. To address this, this study developed a new variable emitter with independent double channels by 3D printing technology. The emitter was designed to provide irrigation and salt-leaching capabilities under two different working water pressure levels (6~10 m and 12~15 m). The basic hydraulic performance of variable emitter was tested by laboratory experiments. Computational fluid dynamics (CFD) combine with path analysis were then used to investigate the effect of hydraulic performance of variable emitter response to the width (w), depth (D), length of flow channel (L), height (h) and distance of tooth (b). The results demonstrated that the discharge of the designed variable emitter smoothly increased from 1.61 L/h^{to 2.08 L/h with the development of working water pressure (6~10 m), and then sharply reach to 4.50 L/h at working water pressure by 12 m. This indicated that variable emitter could be used for both irrigation and salt-leaching under two water pressure levels. Considering the practical application requirements of related to irrigation quota and salinization degree in most farmland in Xinjiang, the suitable flow channel parameters of variable emitter were recommended. For instance, the appropriate values for w, D, h, L and b of variable emitter were 0.60 mm, 0.60 mm, 0.80 mm, 8.80 mm, and 0.6 mm for the utilization on slight saline-alkali farmland, respectively.}

Automatic controlling of border irrigation is an crucial measure to improve irrigation quality and reduce labor demand. To explore the optimal selection of control factors in the automatic controlling border irrigation system, this study obtained the natural parameters of the border field through the observation experiment of border irrigation. These parameters were then combined with the WinSRFR model to simulate the border irrigation process and analyze the effects of the automatic controlling border irrigation system on the flow movement process and soil water infiltration distribution. The results showed that both the water cut-off distance and cut-off time had similar regulating effects on the process of surface flow advancing, receding, soil water infiltration distribution and irrigation quality. For a typical test field with 100m border length, varying cut-off ratios of 70%, 75%, 80%, 85%, and 90% corresponded to the irrigation amount of 70mm, 80mm, 90mm, 100mm and 110mm respectively. Water cut-off time had a greater effect on flow advance and regression in the back part of the border, but had a lesser effect on flow advance and regression in the front part of the border. Soil water infiltration distribution in the front part of the border could not be significantly changed by different water conversion ratios or irrigation amounts. The irrigation efficiency and irrigation uniformity in front of the border can be more effectively controlled by regulating flow rate than by stopping distance and stopping time. Therefore, it is recommended to control the irrigation amount in the automatic controlling border irrigation system that prioritized economy, and to control the flow in the automatic control border irrigation system that pursued precise control.

In order to solve emitter clogging problem of drip irrigation caused by fine sediment particles smaller than 0.10 mm in the Yellow River. Based on the literature review, research progress on the physical clogging mechanism of drip irrigation emitters by using irrigation water of high sand content is reviewed, and further research direction is put forward. In drip irrigation with muddy water of high content of fine sediment particles, emitter clogging is mainly caused by the combined effects of sediment content, sediment particle size, and particle size distribution. Changes of working conditions for drip irrigation system, such as dynamic variations of working pressure, can help to remove fine particles such as silt and clay from the flow channel, and promote the discharge of larger sediment particles from the flow channel. Higher irrigation water temperature enhances the emitters' resistance to physical clogging. Aeration and magnetization of muddy water can change the hydraulic characteristics of water flow and the motion law of suspended sediment, increasing the dragging force of water flow and reducing the sediment accumulation in the pipe. In addition, fertilization enhances the flocculation between sediment particles and significantly accelerates the emitter clogging in drip fertigation with muddy water. The sediment content, particle size, and particle size distribution of muddy water are crucial factors leading to physical clogging of emitters. Identifying the sensitive sediment content and particle size segments that are prone to cause drip irrigation emitter clogging, selecting suitable fertilizer types and fertilization concentration thresholds, and optimizing the working conditions of drip irrigation system are effective measures to modify the transport and deposition laws of sediment particles in capillary tubes. These measures can help to delay drip emitter clogging process, and improve the utilization efficiency of fertigation. Improving engineering treatment measures using uniform experimental method, making full use of modern testing means, and combining with the actual production practice in the field are necessary means to solve emitter clogging problem for drip irrigation.

To enhance the performance of precast concrete lined channels in cold regions, several issues need to be addressed, such as the self-weight of lining panels, small size, and low assembly efficiency, this study explores the use of ceramic fiber concrete for lining channels. Based on the orthogonal test method, 9 groups of ceramic fiber concrete and 1 group of C35 ordinary concrete mechanical properties before and after freezing and thawing tests were carried out. Additionally, numerical simulations of freezing and expansion were conducted to analyze the changes in freezing and expansion resistance of the lined channels. The results show that: the compressive strength of ceramic fiber concrete is influenced by shale ceramic volume substitution rate > polypropylene fiber (PP) dosage > ceramic pre-wetting time, and the tensile strength is influenced by PP dosage > shale ceramic volume substitution rate > ceramic pre-wetting time. Furthermore, the loss rate of compressive and tensile strength of ceramic fiber concrete is lower than that of ordinary concrete after freezing and thawing. The change of anti-freezing and expansion performance of the lining channel numerical simulation is consistent with the change trend of material performance, and the change of anti-freezing and expansion performance of ceramic fiber concrete is consistent with the change trend of material performance. The trend of material performance change is consistent, the loss of frost resistance of ceramic fiber concrete lined channel is less than ordinary concrete lined channel, the optimal loss of frost resistance is reduced by 4.68%, while the weight of lining plate is reduced by 18.47%.The use of ceramic fiber concrete as a channel lining material offers the advantage of assembly with obvious light weight.

In order to thoroughly investigate the water measuring performance of an airfoil column measuring flume applied to the U-shaped channel, four different contraction ratios were established to conduct hydraulic performance experiments. By analyzing the upstream water level, flow rate, contraction ratio, a flow rate formula was fitted. The accuracy of flow measurement, upstream Froude number, and critical submergence were also analyzed. The experimental results show a strong correlation between water level and flow rate in the airfoil column measuring flume, with the a coefficient of correlation of R ²=0.998. The flow formula fitted from the test data is concise and easy to use, with an average flow error of 2.47%. The upstream Froude number was less than 0.3, and the critical submergence reached a value of 0.887. Compared with a traditional flow measuring flume on a U-shaped channel, the airfoil column measuring flume exhibited a simple and user-friendly flow formula. Additionally, the structure of the airfoil column measuring flume in U-shaped channel provides novel insights and reference for further research.

Permeable Concrete Infiltration Irrigation technology (PCII) is a innovative irrigation technology that can transport water to the deep roots of crops. To explore the water-saving effect of PCII and clarify its impact on fruit tree yield and water use efficiency (WUE), this study focuses on Nanfeng clementines in the red soil hilly area of Jiangxi Province. Through field irrigation control experiments, the effects of three irrigation methods, namely permeable concrete infiltration irrigation, flood irrigation (CK), and drip irrigation (DI), on soil moisture dynamics, fruit growth, yield, quality, and water use efficiency of Nanfeng clementines were studied. The research results indicate that compared to CK and DI, the average soil volume moisture content of each soil layer under the PCII irrigation method is higher and the fluctuation amplitude is smaller. Compared with DI, the volume of Nanfeng honey orange fruit under PCII increased by 0.79% to 2.06%, 0.35% to 4.29%, 1.18% to 4.59%, and 0.38% to 0.85% during the young fruit stage, fixed fruit stage, fruit enlargement stage, and fruit maturity stage, respectively. The growth rate increased by 1.21% to 1.39%, 1.29% to 1.33%, and 0.93% to 1.09% during the fixed fruit stage, fruit enlargement stage, and fruit maturity stage, respectively. Compared with CK, the sugar content increased by 11.47% to 15.15% and 13.70% to 13.91% during the fruit enlargement and ripening stages, respectively. Compared with CK treatment, the yield and water use efficiency of PCII increased by 15.69% to 17.15% and 43.13% to 43.60%, respectively. Furthermore, compared with DI treatment, the yield and water use efficiency of PCII increased by 1.58% to 2.49% and 4.84% to 5.23%, respectively. Therefore, the utilization of permeable concrete infiltration irrigation can help improve the yield and quality of Nanfeng clementines in red soil hilly areas, and achieve efficient utilization of water resources.

Exploring the soil erosion status in the Changbai Mountain region caused by factors such as extreme precipitation, complex topography, and vegetation destruction can provide scientific reference for local soil and water ecological protection. Using the modified RUSLE, trend and correlation analysis, the spatial pattern and temporal distribution characteristics of soil water erosion in Changbai Mountain were quantitatively analyzed. Additionally, the relationship between soil water erosion and climate, vegetation coverage and topographic driving factors was explored. The results show that the average soil water erosion modulus in the Changbai Mountains from 2001 to 2020 exhibited a spatial pattern of "high in southwest and low in northeast". Compared with other land types, grassland, unused land and forest land were more prone to soil water erosion. Over the past 21 years, the soil water erosion modulus increased at an average rate of 0.025 5 t/(hm²·a), and the areas showed an increasing trend of soil water erosion modulus accounted for 68.3% of the total study area. The erosion grade was mainly mild, and the proportion of mild erosion also showed an increasing trend, indicating an overall improvement in the soil erosion situation in the area. In the future, the risk of soil erosion is higher in the central and northern part of Jilin City and some parts of Yanbian Prefecture. Soil water erosion was positively correlated with precipitation, elevation and slope, while negatively correlated with air temperature and vegetation coverage. The grassland and woodland areas with elevation exceeding 1 000 m or slope steeper than 20° are the key topographic areas for soil and water control.

In the process of interaction between runoff and soil, soil solute will migrate with runoff. The indoor experiments are conducted to investigate the loss pattern of solute and the change law of solute concentration in two directions on saturated soil, including vertical infiltration and slope runoff. The results as follows: During runoff, the solute rate decreases, and the amount of solute loss also decreases, eventually reaching a stable state over time. As a result, a power function is more suitable for describing such changes than index; In the vertical direction, the penetration and diffusion of soil solute in the lower layer are affected by the depth. As the depth increases, the solute concentration first increases and then decreases, and tends to stabilize. Therefore, a logarithmic description is suitable for capturing this pattern. On the surface of the slope, the migration rule of soil solute with runoff is clear that the concentration of soil solute is higher at a distance compared to nearby areas. So a multi-order polynomial model is more suitable for describing concentration change. There is a clear boundary for the change of solute concentration, and the change regularity of solute concentration is poor below the boundary, but overall, it shows a decreasing trend.

The hydraulic characteristics of the litter layer can significantly influence the runoff process on slopes. Rainfall patterns and slope can influence both litter layer runoff and infiltration processes. In this study, various combinations of litter layers (5 cm leaf litter + 5 cm decomposed layer, 10 cm leaf litter), rainfall patterns (increasing, decreasing, and uniform), and two different slopes (15°, 20°) were selected for artificial rainfall simulations to analyze litter layer infiltration and lateral runoff. The results revealed the following: ①As rainfall intensity increased, the time required for litter layer infiltration to reach stability decreased, and the stable infiltration rate increased. ②Under the same rainfall pattern and slope conditions, the average infiltration rate was higher for the 5 cm leaf litter + 5 cm decomposed layer compared to the 10 cm leaf litter, while the lateral runoff rate was lower for the former. ③Compared to the uniform rainfall pattern, the average infiltration rate for the 5 cm leaf litter + 5 cm decomposed layer decreased by 10.8% to 36.4% under increasing and decreasing rainfall patterns, while the average lateral runoff rate increased by 14.3% to 19.0%. All rainfall patterns demonstrated that the uniform pattern had the highest average infiltration rate and the lowest average lateral runoff rate, with no significant difference observed between increasing and decreasing patterns. ④Under the same litter layer and rainfall pattern conditions, the average infiltration rate of the 20° slope was reduced by 4.3% to 35.9% (P < 0.05) compared to the 15° slope, while the lateral runoff rate increased by 6.0% to 20.3% (P < 0.05).

The analysis of the effects of irrigation on peanut yield and water use efficiency (WUE) and the differences in peanut yield and WUE under various irrigation patterns can provide a theoretical basis and data support for efficient peanut irrigation in northern China. In this study, the author collected data from nearly 40 years of peanut field irrigation experiments in the northern region, grouped them according to irrigation method, irrigation quota, irrigation frequency, and irrigation stage. The author quantitatively analyzed the combined effects of irrigation on peanut yield and WUE and their influencing factors using Meta-analysis with no irrigation as a control. The results reveal that irrigation enhances peanut output and WUE by 16.86% and 2.62% in the northern region, respectively, compared to no irrigation (P<0.05). Notably, irrigation has a more significant impact on peanut yield and WUE in North China compared to Northeast China. When adopting the measures of border irrigation, irrigation quota >90 mm, irrigation frequency ≥4 times, or whole growth stage irrigation, the peanut yield is higher with increases of 20.42%, 29.87%, 25.89%, and 29.84%, respectively (P<0.05). The peanut WUE enhancement is more significant when choosing drip irrigation, irrigation quota <30 mm, irrigation once, or irrigation at flower-pegging stage, with increases of 2.76%, 8.39%, 5.27%, and 7.96%, respectively. Random forest results show that in the northern region, irrigation quota is the most important factor influencing the effect of irrigation on peanut yield and WUE, followed by irrigation stage. As a result, it is recommended that the irrigation quota for peanut growing areas in the north should not exceed 150 mm. The appropriate irrigation quota for the northeast region is 30~60 mm, whereas the quota for the north China region is 90~150 mm. Optimal practices for achieving coordination between peanut yield increase and WUE improvement include drip irrigation, irrigating 2~3 times whole growth stage, or irrigating mostly during the flower-pegging stage and podding stage, with supplementary irrigation during the seedling stage. It is more conducive to the coordination of peanut yield increase and WUE improvement, so as to realize the efficient irrigation of peanuts in northern China.

This study aims to address the issue of spatial and temporal variations in agricultural water use efficiency and analyze the factors influencing these variations. A variety of mathematical geographic models were combined to measure the agricultural water use efficiency of each province by using the non-expected output super efficiency SBM model. The Tobit model was utilized to explore the main influencing factors of agricultural water use efficiency. Based on the measured results, the spatio-temporal geographical weighted regression model (GTWR) was used to analyze the influence degree and spatio-temporal difference of each factor on agricultural water use efficiency. The results indicate that although there has been a noticeable improvement in the efficiency of agricultural water use in China, the overall efficiency remains relatively low, with significant differences observed among provinces and regions. Annual precipitation, proportion of agricultural water use, proportion of water-saving irrigation area, per capita agricultural output value and import and export value of agricultural products were the main influencing factors of agricultural water efficiency, and the proportion of agricultural water use and per capita agricultural output value were the most negative and positive factors, respectively. The natural conditions and agricultural production environment of different regions lead to significant variations in the influencing factors of agricultural water use efficiency. The prosperity of foreign trade in Northeast China can effectively promote the improvement of agricultural water use efficiency. The traditional flood irrigation and cluster irrigation in the Yellow River Basin result in significant water wastage. The higher agricultural production level in the developed areas of the lower reaches of the Yangtze River basin drives the development of the middle and upper reaches; The abundant precipitation in the southern coastal area and southwest area alleviates the pressure of water shortage, and the impact of water saving is insufficient. The disadvantage of geographical location and economic conditions in northwest China leads to low water use efficiency. It is recommended that all regions should take targeted measures according to local conditions to promote the improvement and continuous optimization of agricultural water use efficiency across multiple dimensions.

In order to investigate the characteristics of water use during the growing period of summer maize in the Huaibei Plain under drought stress conditions, and to analyse the field water movement and transference laws in the precipitation-soil-crop continuum. Stable hydrogen and oxygen isotope values of precipitation, soil water, plant water, and groundwater were determined and analysed during different growing periods by field experiments and indoor analyses. Stable hydrogen and oxygen isotope techniques were employed to examine the isotopic distribution characteristics of the water bodies, and direct comparison and multivariate linear regression methods were used to analyse the sources of summer maize root water uptake and their contributions. The local meteoric water line at the Wudaogou Experimental Station was δD = 7.26 × δ¹⁸O + 3.11（R ² = 0.98）, with a slope and intercept smaller than those of the global meteoric water line. This indicates that there was an evapotranspiration-enrichment process of precipitation in the landing process. Soil water hydroxide isotopes showed a clear gradient distribution in the vertical profile. Under drought stress conditions, summer maize primarily absorbed soil water at depths of 0~20, 20~40 and 40~60 cm during jointing-tasseling stage, with the contribution rates of 21.8±13.6 %, 25.5±20 % and 25.1±18.2 %, respectively. The soil water at 0~20 cm was mainly absorbed during tasseling-filling stage, and the contribution rate was 68.6±3.6%. The soil water at 0~20 cm was mainly absorbed in the filling-maturity stage, and the contribution rate was 72.0±0.9%. Summer maize roots preferentially use shallow soil water, which mainly derived from atmospheric precipitation. In the area with shallow groundwater depth, the root water absorption depth of summer maize remains shallow throughout the whole growth period under drought conditions. Therefore, it is considered to change the irrigation method during the growth period to enhance the utilization rate of irrigation water.