Brackish water irrigation is a possible solution to alleviate the shortage of agricultural freshwater in coastal areas, but it is difficult to use brackish water irrigation in salinized irrigation areas. In order to investigate how to use brackish water irrigation scientifically and reasonably in salinized irrigation areas, this study takes the Kendong Irrigation Area in the Yellow River Delta as the study area, and adopted field experiments combined with the HYDRUS-2D mathematical model simulation method to study the effects of soil water and salt transport in winter wheat fields irrigated with brackish water in salinized irrigation areas in the coastal region. Validation results showed that HYDRUS-2D could accurately simulate the soil water and salt distribution under brackish water irrigation, and the simulation results showed that the soil water content of the 0~100 cm soil layer did not differ significantly among the different brackish water irrigation scenarios by setting up four scenarios with 1 g/L (G1), 2 g/L (G2), 3 g/L (G3), and 4 g/L (G4) under the irrigation quota of 750 m³/hm². The simulation results showed that there was little difference in soil water content between the 0~100 cm soil layer under different brackish water irrigation schemes, and under the same brackish water irrigation scheme, except for the 0~20 cm soil layer, soil water content showed a "rising-declining-steady" trend, and soil water content was obviously stratified vertically, with deep layers having a higher soil water content compared with the shallow soil layer; the soil salinity in the 0~40 cm soil layer under different brackish water irrigation schemes had a tendency to increase, and that in the 60~100 cm layer soil salinity had a tendency to decrease. The soil salinity in the 0~40 cm soil layer under different brackish water irrigation schemes had a tendency to increase, and the soil salinity in the 60~100 cm soil layer had a tendency to decrease, and the soil salinity was obviously stratified vertically, with the deep layer having a lower salinity compared to the shallow layer; the re-salinization rate increased with the mineralization degree of brackish water irrigation, and the desalination rate decreased as the mineralization degree of brackish water irrigation.G4 caused the average soil salinity of the main rooting zone of winter wheat (0~40 cm) reach 3.26 g/kg, and the average soil salinity in the main rooting zone (0~40 cm) reached 3.26 g/kg. Under high salt stress, with a desalination rate of 39.60% and a re-salinization rate as high as 68.95%. Considering multiple indicators, it is comprehensively proposed that the mineralization level of winter wheat irrigated with brackish water should not exceed 3 g/L during the critical reproductive period in coastal salinized irrigation area.

The investigation of water requirement patterns for fig trees (Ficus carica L.) under different irrigation methods and the accurate prediction of crop water demands is of paramount importance in fig trees cultivation, the water requirement (ET _c) patterns of fig trees under different irrigation methods were analyzed and the crop coefficient (K _c) empirical values were estimated based on the experimental data from 2022 to 2023 in Qingyuan, Guangdong. Using the Hargreaves–Samani model and single crop coefficient method, the water requirement of fig trees was forecasted based on public weather forecasts with a 14 day lead time. The results showed that furrow irrigation had the highest ET _c among the different irrigation methods, with an average daily ET _c of 2.44 mm/d in 2023, followed by sprinkler and surface drip irrigation, with an average daily ET _c of 2.23 mm/d and 2.04 mm/d, respectively, and subsurface drip irrigation, with the smallest ET _c of 1.92 mm/d. May to September is the peak period of water demand for fig trees. The single crop coefficient method recommended by the Food and Agriculture Organization of the United Nations (FAO) was used to derive the K _c empirical values, and the K _c of subsurface drip irrigation < surface drip irrigation < sprinkler irrigation < furrow irrigation. The temperature forecasting accuracy is high, and the forecasting accuracy of the minimum temperature is better than that of the maximum temperature. The calibrated HS model has good ET ₀ forecast accuracy, with an average correlation coefficient of up to 0.86. The accuracy of the fig ET _c forecasts was lower than that of ET ₀ forecasts, and the correlation coefficients ranged from 0.68 to 0.74. The forecasting model of fig ET _c can provide forecasts of fig water demand for the next two weeks, which can provide information for farmers to make accurate irrigation decisions.

To explore the effect of magnetized brackish water irrigation on the infiltration and salt ion migration characteristics of saline soil in southern Xinjiang, the constant magnetic field intensity of 400 mT was used to magnetize the brackish water with salinity of 0, 2, 3 and 5 g/L, respectively. An unmagnetized treatment was used as the control. We compared and analyzed the effects of cumulative infiltration, wetting front migration distance and total salt, desalination rate, salt ions and SAR in different soil profiles after leaching. The results showed that: The infiltration of magnetized brackish water reduced the cumulative infiltration and wetting front depth in the same time. Also, it reduced the infiltration rate of Philip infiltration model. The soil water content was 5.00%~6.29% higher than that of unmagnetized brackish water. The magnetized brackish water irrigation treatment significantly reduced the soil salt content, and the total salt content in the 0~50 cm soil was 11.79%~41.64% lower than that of the unmagnetized treatment. Under the same magnetization intensity, the soil salt content increased with the increase of salinity, and the desalination rate decreased with the increase of salinity. Under the same salinity, the salt content of magnetization treatment is lower than that of non-magnetization treatment, and the desalination rate is higher than that of non-magnetization treatment. Magnetized brackish water irrigation was beneficial to reduce the content of salt ion in soil. The contents of K⁺, Na⁺, Ca²⁺, Mg²⁺, HCO {}_{\mathrm{3}}^{-}, Cl^-and SO {}_{\mathrm{4}}^{\mathrm{2}-} in 0 ~ 50 cm soil layer were 16.90%~25.97%, 43.62%~64.68%, 11.15%~31.44%, -8.12%~49.07%, -74.14%~13.43%, 21.46%~52.81% and 6.66%~13.10% lower than those in unmagnetized treatment. Magnetized brackish water irrigation treatment significantly reduced soil SAR at 0~50 cm soil depth.

Soil salinization is a global problem, which seriously restricts the development of agriculture. Understanding the law of water-salt transport is the key to improving and preventing soil salinization. In cold and arid areas during the non-tillage period of farmland, the movement of soil water and salt is primarily influenced by freeze-thaw cycles, where alternating positive and negative temperatures play a crucial role. In this paper, based on the freeze-thaw cycle, starting from the positive and negative temperature effects, a series of research results such as water-heat-gas-force-salt coupling are reviewed. Furthermore, the generation of positive and negative temperature driving forces and the development of numerical models and experimental research are analyzed. On this basis, the future development direction of soil salinization research under changing environmental conditions is prospected. Saline-alkali land is one of the most important reserves cultivated land resources in the world. It is particularly important to use saline-alkali land reasonably and scientifically to improve saline soil and prevent further salinization of soil. The improvement of saline-alkali land highlights the trend of water saving, ecology and low energy consumption in agricultural development. Studying the driving mechanism and ecological regulation mechanism of soil salinity evolution under different conditions is of great significance for improving soil salinity.

Gravel is widely distributed within soils and on their surfaces, significantly affecting soil characteristics and ecosystem functions. To systematically understand the research progress in the field of soil environment response to gravel, and explore its current research hotspots and future development trends. Utilizing the Web of Science (WoS) and China Knowledge Network (CNKI) databases, along with the help of Citespace and VOSviewer visualisation software, we quantitatively reviewed and visual analysed domestic and international research in the field of soil environment response to gravels from 2000 to 2022 in terms of the number of publications, authors, countries, institutions, journals, and the co-occurrence of keywords and their evolution process. The results showed that the number of publications in this field has shown a rapid growth trend both domestically and internationally, and the number of publications in Chinese literature was higher compared to English literature. China, the United States, Belgium, and the United Kingdom were once among the top four countries in terms of English literature publication volume. Chinese scholars published the most papers, accounting for 47.34% of the total English literature, and were the main force in the research field of soil environment response to gravel. Research in this field mainly focused on the impact of single characteristics of gravel (gravel coverage, gravel size, gravel location, etc.) on hydrological processes, ecological succession, and environmental benefits. Consequently, in the future, we should continue to strengthen research on the response mechanism of soil hydrological processes to gravel, the migration mechanism of nutrients between gravel soil plants, and the internal interaction effects of the “gravel microbial plant” system. This study can provide new ideas and methods for ecosystem services and agricultural production with similar soil conditions globally, so as to realise the goals of water-saving, efficient and high-yielding agricultural production, and provide a theoretical basis for ecological services such as soil and water conservation.

To explore the optimal spacing for combined micro spray tapes under the conditions of longitudinal structural optimization, single-root micro spray tapes with a folded diameter of 42mm and a total length of 40m, including slant 3-hole and slant 5-hole types, were selected for experimental testing of water distribution intensity. Subsequently, using the cubic spline interpolation method, water distribution intensity at each collection point was interpolated from the experimental data. After interpolation, the water distribution intensity of two identical micro spray tapes was superimposed for different combination spacings. The results were analyzed using contour maps of water distribution intensity and uniformity. The findings indicate that the interpolation error of the water distribution intensity using the cubic spline method is less than 7% for micro spray tapes. Structural optimization enhances the water distribution intensity and uniformity at the end of the micro spray tape. Utilizing a structural optimization ratio of 1∶1 and a combination spacing of 1.45 R achieves a maximum uniformity of 69.1% for combined spraying.

The tasks of the irrigation robot's full coverage operation have obvious spatial parallelism. As the full coverage range expands, during the decomposition stage of the coverage area, it is necessary to fully consider how to decompose the entire area into subareas. However, irrigation robots are limited by their visual perception area, making it difficult to accurately match and connect the nearest endpoints between path segments, resulting in errors in the connection of local road points and lines, making it difficult to effectively achieve full coverage. To address this issue effectively, a full coverage path planning method for irrigation robots is proposed. By using a fast search random algorithm to expand the boundary detection of the target area, considering the limited perception range of visual sensors, the grayscale centroid method is used to perform boundary extraction of the area view, and a map is established based on the extraction results. A sequence of line segments is established on the map, connecting some path segments using the Manhattan minimum distance principle, and form multiple arched line blocks. Using the divide and conquer algorithm to match and connect the nearest endpoint pairs between various bow shaped line blocks, in an improved A* algorithm is introduced for global and local road point connectivity and line connection, achieving full coverage path planning for the irrigation robots. The experimental results show that for simple irrigation areas, the path repetition rate of this method is 0.041%, and the irrigation coverage rate is 98.90%; For complex irrigation areas, the path repetition rate of this method is 0.017%, and the irrigation coverage rate is 99.87%. This indicates that for different irrigation environments, this method can achieve ideal path planning, not only maximizing full coverage, but also effectively reducing path redundancy, and obtaining an ideal full coverage path planning scheme for irrigation robots.

In order to study the difference in hydraulic performance between the truss sprinkler with jet pulse tee and the ordinary truss sprinkler, the experimental sprinkler was equipped with four Nelson D3000 refractive sprinklers mounted 1m above the ground. The working pressures of 100 kPa, 150 kPa, and 200 kPa, and nozzle spacings of 3.0 m, 3.5 m, and 4.0 m were set up to carry out the all-factor combination test. The water distribution of fixed position spraying and mobile spraying of the jet pulse tee irrigation machine and the water distribution of the line spraying water with the installation of ordinary tee were tested using a five-row, nine-column rain gauge array with a spacing of 500 mm. The results of the experiment are shown below. In the fixed spray test, at inlet pressures of is 100 kPa, 150 kPa and 200 kPa, the Christiansen uniformity coefficient and distribution uniformity coefficient of the 4m nozzle combination spacing are the highest, which are greater than 90% and 84%, respectively. In the spraying test, when the inlet pressure of the nozzle was 100 kPa, 150 kPa and 200 kPa, the peak water depth of the pulse group was reduced by 27.1%, 27.9% and 28.6%, respectively, and the Christiansen uniformity coefficient increased by 17.1%, 12.6% and 3%, respectively, and the distribution uniformity coefficient was increased by 24.2%, 11.2% and 9.5%, respectively. The pulse flow generated by the jet pulse tee can effectively reduce the peak irrigation intensity of the truss sprinkler and improve the uniformity of the water distribution of the truss sprinkler.

In small watershed runoff simulation, the selection of suitable evapotranspiration products from multiple sources can improve the accuracy of hydrological model runoff simulation. In this study, based on the principles of remote sensing evapotranspiration, we selected the GLASS product based on machine learning models, the PET_PU_3H025_002 product based on land surface models, and the MOD16, GLEAM, and SSEBop products based on remote sensing models as our research objects. This study focuses on the Little Washita watershed, analyzing the spatiotemporal variation characteristics of evapotranspiration products by calculating their multi-year regional averages. Additionally, it explores the applicability of multiple evapotranspiration products within the CREST hydrological model. Utilizing the NSCE, Bias, and CC indices, coupled with single-index evaluation methods and comprehensive multi-index evaluation methods, we compare the simulation results between the calibration and validation periods. The results show that ①The spatial and temporal distribution patterns of five remote sensing evapotranspiration products show significant differences in multi-year averages. PET_PU and SSEBop products tend to have relatively higher estimated values within the region, while MOD16 products show relatively lower values. Conversely, GLASS and GLEAM products demonstrate similar ranges of variation in their regional multi-year averages, consistently maintained between 2.2 mm/d and 2.4 mm/d. ②The model exhibits relatively accurate simulation of peak timing, yet disparities exist in peak flow simulation. Comparing using the Bias index during the calibration period, GLEAM products demonstrate the smallest deviation, while MOD16 exhibits the largest. In the validation period, the effectiveness of streamflow simulation noticeably decreases compared to the calibration period, as indicated by NSCE, Bias, and CC indices. ③The differences among various remote sensing evapotranspiration products in small watershed streamflow simulation is minor. Employing a comprehensive multi-index evaluation method, GLEAM and GLASS products demonstrate superior performance.

It is crucial to analyze the abrupt changes of rainfall runoff in different water periods of high and low seasons for accurately understanding the change law of water resources in Lijiang River and scientifically implementing the regulation of water resources. In this paper, bsed on the flooding, normal and dry season, the monthly scale series of precipitation runoff from 1968 to 2021 at Guilin, Yangshuo and Pingle hydrological stations located in the upper, middle and lower reaches of the Lijiang River are selected to analyze the annual and interannual distribution of precipitation runoff. Mann-Kendall method and slide t-test method were used to analyze the mutation point and its causes in combination with the flood control in the upper reaches of the Lijiang River and the construction and operation of the Lijiang River water supplement project. Additionally, the contribution rate of precipitation and human activities to the abrupt change of runoff is analyzed by using the method of comparing the change rate of cumulative slope. The results show that: ①the annual precipitation in the upper reaches of the Lijiang River Basin shows an increasing trend, while the lower reaches experience a decreasing trend; The annual runoff shows an overall upward trend. ②The abrupt change points of the three stations in the upper, middle and lower reaches of the Lijiang River Basin in the flooding, normal and dry season are not consistent. ③The impact of water conservancy project construction on runoff is obvious.

The Huaibei Plain is an important grain production base in China. It is crucial to analyse the drought spatial and temporal variation characteristics and the applicability of different drought indices to improve the drought risk resistance of the Huaibei Plain, as well as to monitor agricultural production and drought conditions. This study utilized the precipitation data from 20 meteorological stations in the Huaibei Plain from 1962 to 2021. Standardized precipitation index (SPI) and Z-index at annual and seasonal scales were calculated, and consistency of the two indices as well as the variability of spatio-temporal change characteristics in the Huaibei Plain were analyzed. Furthermore, the applicability of the two drought indices was investigated by combining with comparative analyses of historical drought data. The results showed that the two indices showed good consistency in the Huaibei Plain at both annual and seasonal scales, and had strong correlation with the rainfall in the region; on the temporal scale, the two indices showed a slow wetting trend in the annual and summer/winter seasons, while a non-significant drying trend in the spring/autumn seasons; on the spatial scale, the drought-incidence area and the frequency of droughts monitored by the Z-index were higher than that of the SPI-index; and the comparative analyses with historical drought data showed that the Z-index was more suitable than the SPI-index in the HuaiBei Plain. Comparison with historical drought data shows that the Z index has a certain degree of continuity compared with the SPI index, is not easy to appear anomalies, and is more consistent with the actual. Comprehensive analyses show that the Z index is suitable for drought monitoring in Huaibei.

To study the effect of automatic drip irrigation frequency on soil moisture and yield in cotton, four treatments were set up in the modern irrigation demonstration area of Changji Agricultural Park in Xinjiang from 2019 to 2020, with the same irrigation quota (W=4 800 m³/hm²), fertilization amount (urea 300 kg/hm², diamine 234.67 kg/hm², potassium sulfate 117.33 kg/hm²), and other agronomic management measures consistent with the field. Three repeated irrigation frequency experiments were conducted on each treatment. The results showed that the cotton seed yield was 5 751.72 kg/hm², 5 434.22 kg/hm², 5 353.71 kg/hm², 5 261.89 kg/hm², and the water use efficiency was 1.20 kg/m³, 1.13 kg/m³, 1.2 kg/m³, and 1.10 kg/m³, respectively, when treated with irrigation frequency (T1:12, T2:10, T3:8, T4:6). The average soil moisture content at 0~40 cm depth was 23.84%~34.51%, 21.45%~32.97%, 19.52%~32.67%, and 16.94%~32.37%. Under the same conditions of climate, soil, field, and management measures, it is recommended to apply automatic drip irrigation to cotton with a frequency of 12 irrigations and a 6-day interval during the growth period.

To investigate the effects of inorganic fertilizer combined with water-soluble organic fertilizer on the growth, yield, and quality of greenhouse lettuce, lettuce was used as the experimental material. Seven different fertilization treatments on lettuce growth were applied. The fertilization treatments were CK (no fertilization), T1 low concentration inorganic fertilizer (N 160 kg/hm²,P₂O₅ 80 kg/hm²,K₂O 80 kg/hm²), T2 medium concentration inorganic fertilizer (N 320 kg/hm²,P₂O₅ 160 kg/hm²,K₂O 160 kg/hm²), T3 high concentration inorganic fertilizer (N 480 kg/hm²,P₂O₅ 240 kg/hm²,K₂O 240 kg/hm²), T4 low concentration inorganic fertilizer+low concentration water-soluble bio organic fertilizer (300 kg/hm²), T5 low concentration inorganic fertilizer+medium concentration water-soluble bio organic fertilizer (600 kg/hm²), T6 concentration inorganic fertilizer+high concentration water-soluble bio organic fertilizer (900 kg/hm²), respectively. Besides, various parameters were measured, including plant height, stem diameter, maximum leaf area, fresh weight per plant, relative chlorophyll content (SPAD value), yield, irrigation water productivity, partial fertilizer productivity, nitrate content, VC content, soluble protein content, and soluble sugar content of lettuce. Finally, the suitable fertilization mode for lettuce growth was further determined through comprehensive evaluation using membership function method. The results indicated that the application of inorganic fertilizer alone, as well as the combination of inorganic fertilizer and water-soluble bio organic fertilizer, both led to significant improvements in plant height, maximum leaf area, fresh weight per plant, SPAD value, and yield of lettuce. In terms of lettuce quality, the application of inorganic fertilizer alone resulted in an increase in nitrate content. However, under the condition of combining inorganic fertilizer with water-soluble bio organic fertilizer, the VC content, soluble protein content, and soluble sugar content of lettuce were all lower compared to the indicators observed when using only inorganic fertilizer. By using the membership function value analysis method to comprehensively analyze the above indicators, T6 was found to be the best fertilization method and the most suitable fertilization mode for drip irrigation greenhouse lettuce growth. T6 resulted in a 28.81% increase in yield, a 30.45% increase in VC content, a 25% increase in soluble protein content, and a 39.10% increase in soluble sugar content compared to the control group (CK). This experiment can achieve the reduction of inorganic fertilizer and increase efficiency, alleviate agricultural pollution, and achieve the goal of water and fertilizer conservation to protect the ecological environment. Additionally, it provides a theoretical basis for greenhouse lettuce production fertilization methods in Shanxi Province.

With the reduction of water quota, the priority of water saving, reduction of pollution and stabilization of grain yield are bound to be the future development direction of Hetao Irrigation District (HID). Ridge with film mulching and furrow irrigation (RMFI) can improve water and fertilizer utilization efficiency, but the mechanisms of water saving and yield increase are not clear. Therefore, spring maize irrigation experiment of five irrigation levels (T1, 200 mm; T2, 275 mm; T3, 350 mm; T4, 425 mm; T5, 500 mm) with RMFI was carried out in HID to study the migration and transformation characteristics of soil water, soil nitrate nitrogen, and soil ammonium nitrogen under different irrigation amounts. The results showed that soil water consumption increased linearly with increasing irrigation amount from 326.8 mm in T1 treatment to 487.1 mm in T5 treatment. The nitrate nitrogen storage at harvest under T2 and T3 treatments was higher than that before sowing, and the fertilizer retention capacity was high. The N content of spring maize kernels in T3 treatment was significantly higher than that in the other treatments. There was no significant difference in grain yield and nitrogen uptake between T3 and T4, T5 treatments. There was no significant difference in nitrogen use efficiency between T3 and T1, T2 treatments. Water use efficiency initially increased and then decreased with increasing irrigation quota. In conclusion, an irrigation amount of 350 mm with RMFI can effectively improve water use efficiency and grain quality of spring maize while saving water, maintaining fertilizer, and increasing yield, contributing to high-quality agricultural development in HID.

This study investigated the optimal irrigation and fertilization levels for enhancing oil sunflower yield and quality in saline-alkali soil under drip irrigation in the Ningxia Yellow River Irrigation area. Oil sunflower was selected as the focus crop, and irrigation water was gully water. Various combinations of three irrigation levels and three fertilization levels were examined to assess their impacts on oil sunflower growth, yield, quality, crop water use efficiency, soil pH, and desalination rate. The CRITIC comprehensive evaluation method was employed for analysis, offering insights for the effective water and fertilizer management of oil sunflower cultivation in saline-alkali soil within the Ningxia irrigation area. The findings suggest that under drip irrigation conditions, the S3F3 treatment displayed optimal growth and yield indices. However, it's noteworthy that although the S3F3 treatment demonstrated the most robust overall growth, it didn't yield a significant difference in output compared to the S2F2 treatment. In terms of water usage efficiency, the S2F2 treatment excelled. Regarding sunflower quality, the S2F3 treatment exhibited the highest crude fat content, whereas the S3F1 treatment had the highest oleic acid content, and the S2F2 treatment had the highest linoleic acid content. In terms of soil pH reduction, the middle-water and high-fertilizer (S2F3) treatment demonstrated superior performance. Additionally, the S2F2 treatment significantly outperformed other treatments in improving the desalting rate, exhibiting an impressive 86.12% increase compared to the control. Based on the CRITIC weight method, it's been determined that the most effective water-fertilizer coupling treatment for conserving water, managing salt levels, increasing yields, and enhancing quality of saline-alkali soil in the Ningxia Yellow Diversion irrigation district, utilizing ditch water as the irrigation source and drip irrigation technology, is the middle-water fertilizer (S2F2) treatment. In this treatment, the salt content of the ditch water is 506 mg/L, the irrigation quota is 1 875 m³/hm², with urea applied at 450 kg/hm² and potassium chloride at 150 kg/hm².

In this paper, numerical simulation and field experiment were combined to calibrate and validate the hydraulic characteristics parameters of the model based on field measured data from 2019 to 2021, and the calibrated model parameters were used to simulate the changes of water stress and deep leakage of drip irrigation apples in 42 groups under different scenarios. HYDRUS-2D model was used to optimize the drip irrigation system of 5-year-old dwarf dense-planted apple trees in southern Xinjiang. The results showed that the optimal drip irrigation system for 5a-age apple trees in southern Xinjiang at different growth stages was 4.5 mm for 6 times, 13.5 mm for 19 times and 9 mm for 7 times, respectively, in the flowering and fruit setting stage, fruit expansion stage, and fruit maturity stage. The irrigation cycle was 3 days, 4 days, and 3 days, respectively.