Abstract:[Objective]Hetao Irrigation District is one of the largest irrigation districts in Northwestern China.However,the imbalance between irrigation and drainage has resulted in soil salinization.The purpose of this paper is to investigate the characteristics of soil salinization in both planted and uncultivated soils in this region,as well as the key environmental factors that influence soil salinization.[Method]Field investigation and laboratory test were conducted to analyze the ion characteristics and its influential factors in cultivated and uncultivated soils.[Result]In the studied area,the predominant anion in both cultivated and uncultivated soils was chloride(Cl-),comprising 59.31%and 58.48%of the composition,respectively.The primary cations were potassium(K+)and sodium(Na+),accounting for 71.32%in cultivated soils and 72.64%in uncultivated soils.Correlation analysis showed that,in cultivated soils,K+and Na+were most correlated with sulfate(SO42-)with a correlation coefficient of 0.87,followed by with Cl-,with a correlation coefficient of 0.66;they were least correlated with HCO3-.In the uncultivated soils,K+and Na+were mostly correlated with Cl-,with a correlation coefficient of 0.93,followed by with SO42-,with a correlation coefficient of 0.73.Key factors affecting salinization in the cultivated soils included SO42-,magnesium(Mg2+),Cl-,K+and Na+,while in the uncultivated soil,they were SO42-,Cl-,K+,Na+and HCO3-.Redundancy analysis showed that salt ions and environmental factors accounted for 13.56%and 20.23%of the variation in salinization in cultivated soils,and 35.17%and 46.17%in salinization in cultivated soils,respectively.Groundwater quality affected soil salt ions the most,followed by soil texture.[Conclusion]Soil salinization in both cultivated and uncultivated soils is severe,with Cl-,K+,Na+and SO42-being the dominant ions.Effective strategies to mitigate soil salinization should focus on improving groundwater quality and optimizing soil texture.

Abstract:[Objective]Soil salinization induced by poor irrigation management poses a significant challenge to irrigated agriculture,reducing soil productivity and crop yields.Estimating soil salinity and its spatial distribution in irrigated areas can help improve soil and irrigation management.The objective of this paper is to use hyperspectral inversion techniques and a develop model to accurately estimate soil salinity and its distribution in the Hetao Irrigation District.[Method]The experiment was conducted in the Shenwu Irrigation Area,where spectral reflectance and salinity data were measured and collected from 253 soil samples.Fifteen spectral transformations were applied to improve the correlation between hyperspectral data and soil salinity.Four models,including multiple linear stepwise regression(MLSR),partial least squares regression(PLSR),support vector machine regression(SVR),and backpropagation neural network(BPNN),were evaluated for their accuracy to estimate soil salinity.The most accurate model was then integrated with GIS to map soil salinity across the region.[Result]① Soil spectral reflectance increased with soil salinity,and spectral transformations significantly improved the correlation between hyperspectral data and soil salinity.② Among the four models we compared,the BPNN model proved to be most accurate and stable.The optimal spectral transformation was the first derivative of the reciprocal logarithm of transformed reflectance data(represented by R),that is,lg(1/R)]'.This model achieved a determination coefficient of 0.825 and a root mean square error of 2.254 g/kg.③ Integrating the BPNN model with GIS enabled estimation of spatial variation of soil salinity.Validation against ground-truth data revealed spatial pattern in soil salinity distribution,with high soil salinity found in the southeast,west and north,and severe soil salinization found in areas adjacent to the lake.[Conclusion]The BPNN model using[lg(1/R)]'we developed is accurate and reliable for estimating soil salinity using hyperspectral data.Combined with GIS,it facilitates accurate mapping of soil salinization in irrigated areas,offering valuable insights for salinity monitoring and sustainable management in the Hetao Irrigation District and similar regions.

Abstract:[Objective]The Jitai Basin,the second-largest grain-producing basin in Jiangxi Province,is highly vulnerable to drought.Understanding its spatiotemporal drought variations is critical for developing effective mitigation strategies and enhancing water resource management in the region.[Method]The analysis was based on precipitation and potential evapotranspiration data measured from meteorological stations in the basin from 1990 to 2020.These data were used to calculate the monthly,seasonal,and annual Standardized Precipitation Evapotranspiration Index(SPEI).Spatiotemporal variations in SPEI were assessed using the Mann-Kendall trend test.Additionally,the Li Index was calculated,based on crop yield loss due to drought,to evaluate agricultural drought severity.Drought severity was categorized into five levels,and both meteorological and agricultural drought variations were examined.[Result]①From 1990 to 2020,the basin exhibited increasing trends in light to moderate aridity at both monthly(0.000 4/10 a)and annual(0.014 8/10 a)scales,though these trends were not statistically significant.Seasonally,aridity increased in spring(0.029 6/10 a),summer(0.007 9/10 a),and winter(0.007 6/10 a),while autumn showed a significant increasing trend in wetness(0.017 6/10 a).Drought events primarily occurred in summer,autumn,and winter,with no extreme drought events observed in autumn.② Spatially,Jinggangshan City and Taihe County were the most prone to monthly drought.Anfu County experienced the highest frequency of summer drought,while Suichuan County was most affected by autumn drought.Annually,Anfu County,Jian County,and Jinggangshan City were identified as the most drought-prone regions.③ The Li Index indicated that the overall frequency of drought events in the Jitai Basin was 67.74%,with moderate droughts accounting for 38.71%.Summer and autumn were most frequently affected by drought,with Ji'an County particularly vulnerable during spring,summer,and winter.[Conclusion]Although drought in the Jitai Basin has shown an increasing trend over the past three decades,the change was not statistically significant.These findings provide valuable insights for developing region-specific strategies to mitigate drought impacts in the basin.

Abstract:[Background and Objective]Soil salinity is a common challenge for crop production in Northwestern China,and various engineering and agronomic methods have been developed to alleviate or reclaim saline-alkali soils.This paper reviews the advantages and disadvantages of drainage engineering methods,including open ditches,buried drains,and boreholes,for treating saline-alkali soils in Ningxia Province.It proposes the most effective drainage methods for saline-alkali soils in different regions,aiming to provide protocols for improving soil management in the province.[Method]This review focuses on work conducted in regions such as Huinong District and Pingluo County in Shizuishan City,Helan County and Xingqing District in Yinchuan City,and Hongsipu District in Wuzhong City.Literature and engineering data were collected from various sources to analyze and identify the appropriate drainage methods for each region.The VOSviewer was used to analyze and summarize key research topics related to drainage engineering methods for reclaiming saline-alkali soils in the province.[Result]①The primary drainage systems for saline-alkali soils in the province include open ditches,supplemented by buried drains and pumping boreholes.Maintenance of these systems should be strengthened to improve their effectiveness and operational efficiency.② In Huinong District and Pingluo County,located in low-lying areas near lakes and wetlands,the soil has low permeability,and buried drains and pumping boreholes are the most appropriate methods to maintain the groundwater table below a critical depth.In areas with clayey soils,combining these methods with soil barrier removal would enhance efficiency.③ In Helan County and Xingqing District(Yinchuan City),the cultivated saline-alkali soils require drainage ditch maintenance and protection.A combination of boreholes and buried drains should be considered based on local conditions.④ In Hongsipu District(Wuzhong City),topsoil salinity can be reduced by leaching using ditch drainage,while salinity in the subsoil can be managed with buried drains or leaching using borehole pumping.[Conclusion]Drainage engineering practices are critical for reclaiming saline-alkali lands in Ningxia Province.Selecting an appropriate drainage method based on regional characteristics is essential to improving reclamation efficiency.Future research should focus on combining engineering,biological,chemical,and physical methods to better manage saline-alkali soils in the province.

Abstract:[Objective]Non-pressurized mesh filters are often installed in front of pumps to filter sediments and debris.In this paper,we study the influence of different irrigation water sources and backwash device parameters on hydraulic performance of anew network filter.[Method]The water flow rate in the experiment ranged from 120 to 160 m3/h,and the sediment concentration in the water varied from 0.2 to 0.8 g/L.The backwash varied from 1 to 20 m/h,and the velocity gradient in the filter box changed from 1 to 4 r/min.A multi factor dispersion analysis method was used to analyze the experimental results.[Result]① The initial sediment concentration had minimal impact on hydraulic performance of the mesh filter,contributing only 0.010 8 to the overall effect.However,the influence of water flow duration on the initial sediment concentration was significant,exceeding 159% .② The fourth model provided the best fit for the overall regression analysis,with a residual value of 0.804 4,significantly higher than other models;its coefficient of determination R2 was 0.986 1.③the optimal performance was achieved when flow rate was 120.198 m3/h,velocity was 1.112 r/min,and self-cleaning flow rate was 19.934 m3/h.The associated a minimum energy loss was 16.024 kPa.[Conclusion]The model we proposed can accurately predict the impact of operation conditions and sediment concentration in the water on the performance of the non-pressurized mesh filters.Selecting optimal operation conditions can minimize the energy loss across the filter.

Abstract:The concept of new quality productivity of agricultural water conservancy represents a new development in advancing water productivity.It is a crucial link in achieving high-quality water resource development.Enhancing new quality productivity of water conservancy is critical for sustainable development of farmlands and promoting high-quality agricultural water management.Specifically,the new quality productivity of agricultural conservancy is a practical approach to advancing agricultural modernization and high-quality development.To accelerate the implementation of new quality productivity in agricultural water conservancy,this paper constructs a research framework based on an in-depth analysis of the relationship between productivity of agricultural water conservancy and overall water conservancy productivity.The framework addresses some key issues,including strategic objectives,system layouts,and essential components in water conservancy.Our analysis focuses on research in the core aspects of agricultural water conservancy productivity and proposes a future perspective of new quality productivity of agricultural water conservancy.These include theoretical research,technological innovations,and farmland transformations.Our analysis provides a theoretical basis for promoting the formation and development of new quality productivity in agricultural water conservancy.

Abstract:[Objective]Cotton production in Xinjiang relies on irrigation.However,in regions with shallow saline groundwater,managing irrigation to avoid soil salinity is crucial to sustaining cotton growth.The purpose of this paper is to elucidate the influence of mulched drip irrigation amount on cotton yield and water use efficiency of irrigation water in regions characterized by shallow saline groundwater.[Method]The experiment was conducted from April 2022 to October 2023.It compared four irrigation amounts:300 mm(W1),375 mm(W2),450 mm(W3)and 525 mm(W4).In each treatment,we measured spatiotemporal changes in soil water and soil salt content,groundwater table and ground salinity,as well as growth,yield and water-use efficiency of the cotton.[Result]① Soil desalination rate increased with irrigation amount.In the W4 treatment,the total soil desalination rate in the 60 cm soil layer varied from 29.78％to 58.19％.② Increasing irrigation amount increased groundwater recharge,but reduced groundwater salinity from 6 g/L to 4-5 g/L,benefiting groundwater utilization by the crop.③ With the increase in irrigation amount,plant height,leaf area index,dry matter accumulation and yield of the cotton increased first followed by a decline.The growth index of cotton under W3 treatment was the best,with a potential yield of 7 127.66 kg/hm2.Water use efficiency decreased with the increase in irrigation amount.[Conclusion]The optimal irrigation schedule for cotton under mulched drip irrigation in the studied area is 450 mm.Although its associated water use efficiency is not the highest,it improves ecological environment,meets ecological water consumption and safeguards crop growth.

Abstract:[Objective]To study the effects of applying different amounts of biochar on the growth and yield of rice in the Jiansanjiang area under flooded irrigation and alternating wet and dry irrigation modes,and to determine the appropriate amount of biochar under different irrigation modes for rice in this area.[Method]The experiment was carried out as a field trial using two irrigation modes:flood irrigation(CF)and alternating wet and dry irrigation(AWD).Additionally,three biochar application rates were used:B5(5 t/hm2),B15(15 t/hm2),and B25(25 t/hm2).Flooded irrigation without biochar treatment was used as the control(CK)to study the effects of different biochar application rates on rice growth and yield under two irrigation modes.[Result]The application of biochar promoted plant tillering and plant height growth under both irrigation models,but the difference with CK was not significant.Biochar application favored rice LAI,dry matter and yield formation in the Jiansanjiang area,with the most pronounced effect in the B15 treatment.The LAI,dry matter mass and yield of rice in B15 treatment under CF irrigation mode were significantly increased by 39.8%,17.0%and 10.0%,respectively,compared with those in CK.The LAI,dry matter mass,and yield of rice in B15 treatment under AWD irrigation model were significantly increased by 36.9%,18.3%,and 11.3%,respectively,compared with those in CK.Irrigation modes had less effect on tillering and plant height of rice under the same biochar application rate,but AWD irrigation model was more favorable for dry matter mass and yield.Mean rice dry matter mass and yield increased by 1.0%and 0.8%,respectively,under the AWD irrigation mode compared to the CF irrigation mode.Water consumption of rice under CF irrigation mode was similar to that of CK,whereas water consumption of rice under AWD irrigation mode was 11.0%less than that of CK.Water use efficiency in AWD irrigation mode increased by 13.3%than that of CF mode.Under the same irrigation mode,rice water use efficiency was significantly higher in the B15 treatment than in the other treatments.Water use efficiency of B15 treatment was 9.7%and 25.5%higher than that of CK under CF and AWD irrigation mode,respectively.[Conclusion]The application of biochar in the Jiansanjiang area can promote the growth and yield formation of rice,and the increase in yield firstly increases with the increase of biochar application rate and then decreases,taking into account the increase in yield,water saving and other factors,the 15 t/hm2 biochar application rate in the AWD mode is the best water-charcoal coupling mode.

Abstract:[Objective]The effect of temperature on plant development is often characterized by degree days or accumulated temperature.In this paper,we investigate how planting date affects accumulated temperature and the consequence for the yield of two ratooning rice varieties.[Method]The experiment was conducted in a rice field in Changsha,central Hunan province.It included two rice varieties:Y Liangyou 900(YLY900),which has a long growth period,and Y Liangyou 911(YLY911),which has a moderate growth period.The seeds of both varieties were sown on March 15(B1),March 20(B2),March 25(B3),March 30(B4),April 5(B5),or April 10(B6)to establish a planting date gradient.In each treatment,we measured physiological parameters including growth duration,yield component,and seed-setting rate to evaluate the physiological development of the crops.[Result]The average annual growth period of YLY911 was 215 days.Its first and regeneration seasons were eight and ten days shorter,respectively,than those of YLY900.Delaying the planting date shortened the vegetative growth period of the first season and reduced the total growth period of both seasons in both varieties.The variation in grain yield in the first and regeneration season,as well as annual yield of YLY911,followed a parabolic relationship,peaking in B2.Conversely,the yield of YLY900 decreased steadily as planting date was delayed.Yields in the first and regeneration season,as well as annual yield,were consistently higher in YLY911 than in YLY900.The primary factors affecting grain yields were the number of ears per unit area and the seed-setting rate.With delay in planting dates,the annual accumulated temperature for both varieties first increased and then declined,peaking in B2.The accumulated temperature in the first and annual seasons for YLY900 was significantly higher than for YLY911,while the accumulated temperature in the regeneration season was lower for YLY900 than for YLY911.Such differences in the regeneration season between the two varieties were statistically insignificant(p>0.05).[Conclusion]For ratooning rice in our studied area,the optimal planting date was March 15 for varieties with long growth period and March 20 varieties with moderate growth period.

Abstract:Arid and semi-arid regions in Northwest China face critical challenges related to soil moisture retention,land degradation,and ecological sustainability.Mulching has been widely applied as an effective soil and water conservation practice.This review summarizes recent research on the effects of different mulching techniques on soil water regulation and ecological functions in these water-scarce regions.Based on a synthesis of domestic and international literature in the past two decades,this review categorizes mulching types-including straw mulch,plastic film mulch,gravel mulch,and biodegradable alternatives-and analyzes their impacts on soil moisture dynamics,temperature regulation,salinity control,and soil fertility.Additionally,it analyzes their role in improving crop productivity and enhancing ecosystem resilience.Mulching significantly improves soil water-holding capacity,reduces evaporation,and promotes stable crop growth.Straw and biodegradable mulches are more ecologically sustainable than plastic film mulches,which,despite their high water retention efficiency,can cause long-term soil degradation and environmental pollution.Gravel mulching,a traditional technique in Northwest China,shows strong performance in reducing surface runoff and preserving soil structure but may be limited by material availability and labor intensity.Mulching plays a key role in improving water-use efficiency and ecological conditions in arid areas of Northwest China.Selection of mulching type should be adapted to local environmental and socio-economic conditions.Future research should focus on the development of sustainable and environmentally friendly mulching materials,as well as long-term field monitoring to assess ecological impacts.

Abstract:[Objective]Water flow in pumps is modeled using computational fluid dynamics(CFD).However,the impact of turbulence model on simulation accuracy remains unexplored.This study aims to address this gap.[Method]We simulated axial water flow in a pump using three turbulent models:the Standard k-ε,RNG k-ε and SST k-ω models.We compared the simulated results with experimental results and analyzed the internal flow fields simulated by different turbulence models.[Result]At steady flow state,the head curves simulated by all three turbulence models were consistent with the experimental curves.Under forward and reverse flow braking conditions,the head calculated by the Standard k-ε and SST k-ω model was close to or slightly higher than that calculated by the RNG k-ε model.Compared to the RNG k-ε model,the Standard k-ε and SST k-ω models reduced the maximum error of calculated head by 0.13 m and 0.22 m,and average error by 0.55 m and 0.48 m,respectively.Under low water flow condition in the forward pump,the maximum and average error of the calculated head by the standard k-ε model were the least;compared to the RNG k-ε and SST k-ω model,it reduced the maximum error of the calculated head by 1.19 m and 0.96 m,and the average error by 0.56 m and 0.68 m,respectively.Under reverse downstream braking conditions,the SST k-ω model was most accurate;compared to the Standard k-ε and RNG k-ε model,it reduced the maximum errors of the calculated head by1.08 m and 1.63 m,and average errors by 0.6 m and 0.9 m,respectively.Under the reverse pump condition,the Standard k-ε was most accurate;compared to the RNG k-ε and SST k-ω models,it reduced the maximum errors of the calculated head by 0.65 m and 0.74 m,and average errors by 0.34 m and 0.44 m,respectively.For other conditions,including positive rotating pump,positive rotating downstream braking,positive rotating and reverse rotating turbine,the simulated internal flow field in the pump was smooth,the simulated external characteristics were close to experimental observations,and simulated results of all three models were similar.[Conclusion]The accuracy of turbulence models for simulating axial water flow in pumps depends on operating conditions.Our results provide insights into selecting appropriate turbulence model for simulating water flow in pumps.

Abstract:[Objective]Southern Xinjiang has limited freshwater but relatively abundant saline groundwater.To optimize the use of these water resources,we investigate the effect of alternate brackish and freshwater drip irrigation with film mulching on soil water and salt movement,as well as seed yield of cotton.[Method]The experiment was conducted at the Xinjiang Alar Modern Agricultural Comprehensive Experimental Station.It compared nine combinations of brackish and freshwater drip irrigation.In each treatment,we measured the spatiotemporal changes in soil water and salt,as well as growth,and seed yield of the cotton.[Result]During the growth period of the cotton,soil water and salt increased with increased use of brackish water.When the amount of brackish water used for irrigation was the same,continuous use of freshwater irrigation in the early growth stage of the cotton was effective to reduce salt content in the root zone.Increasing the use of brackish water in irrigation inhibited crop growth.Moderate use of brackish water in the flowering and boll development stages can promote reproductive growth,however,excessive use would significantly reduce the weight of single bolls.Appropriately alternating brackish and freshwater irrigation not only ensures vegetative growth in the early stages but also promotes reproductive growth during flowering and boll development stage of the cotton.[Conclusion]In Southern Xinjiang,alternating brackish and freshwater in drip irrigation with film mulching should keep the brackish water ratio below a specific threshold.Its usage should be minimized during the seedling,budding,and early flowering stages,but can be increased during the flowering and boll development stages.In this experiment,the optimal irrigation sequence was freshwater-freshwater-brackish water.

Abstract:[Objective]Subsurface drip irrigation is a water-saving technique that involves burying emitters in the soil.Its efficacy depends on irrigation amount.This paper investigates the impact of irrigation amount in subsurface drip irrigation on root growth and water use efficiency of maize cultivated in the Xiliao River Plain,Northeastern China.[Method]The experiment was conducted in a maize field in the Keerqin District of Tongliao City,comprising six treatments with its associated irrigation amount being 220 mm(CK),195 mm(W1),170 mm(W2),145 mm(W3),120 mm(W4),and 95 mm(W5),respectively.For each treatment,we measured root distribution and water use efficiency.[Result]The spatial distribution patterns of root dry matter,root length,root surface area,and root diameter in the 0-40 cm soil layer at the maturity stage were similar across all treatments.As the irrigation amount decreased,these root characteristics initially increased and then decreased.The total water consumption of the maize during its growing season decreased with reduced irrigation amount,while the relationship between kernel yield and irrigation amount followed a quadratic pattern.With increasing irrigation amount,water use efficiency initially increased and then declined,with W2 achieving the highest water use efficiency at 2.46 kg/m3.Grain yield showed significant positive correlations with root weight density,root length density,and root surface area density in the 0-20 cm soil layer,and root diameter in the 30-40 cm soil layer.Net benefit increased with reduced irrigation among initially and then declined,with the highest net benefit of 20 098 Yuan/hm2 achieved when the irrigation amount was 170 mm.[Conclusion]Subsurface drip irrigation is a water-saving technology,applicable for maize production in Xiliao River Plain in the northeastern China.The optimal irrigation amount was 170 mm.

Abstract:[Objective]Accurate measurement of channel flow is essential for effective irrigation district management.This study evaluates the hydraulic performance of a portable triangular-central flume for measuring water flow in rectangular channels.[Method]Physical tests were conducted under six different flow rates(0.031-0.093 m3/s),four top angles(45°-90°),and three shrinkage ratios(0.375-0.625).Hydraulic performance parameters,including water surface profile,Froude number,backwater height,and head loss under varying operating conditions,were obtained through theoretical calculations and analysis.Flow equations were derived using both hydraulic and dimensional analyses.[Result]The water surface profile variation can be divided into four distinct regions:the upstream backwater zone,the rapid transition zone,the post-jump transition zone,and the downstream stable zone.The upstream Froude number ranged from 0.21 to 0.39,while backwater height varied between 4.28 cm and 18.53 cm.Head loss ranged from 7.13%to 32.82%.The relative error of the flow equations derived from hydraulic and dimensional analyses was between-5.98%and 5.02%and between-3.23%and 2.03%,respectively.The optimal location for measuring water depth in the flume was determined to be 0.5 m upstream of the flume throat.[Conclusion]The flow equation derived from dimensional analysis provides more accurate measurements compared to conventional flumes.The flume exhibits optimal hydraulic performance when the shrinkage ratio is between 0.5 and 0.625.Among the tested top angles,a 60° configuration yielded the best hydraulic performance.The portable triangular-central flume offers a simple yet effective method for measuring flow while maintaining strong hydraulic efficiency.These findings serve as a valuable reference for designing flow measurement flumes in irrigation canal systems.

Abstract:[Objective]Reducing groundwater use for irrigation has been a key mandate in the Hebei Plain to promote sustainable agriculture.Improving irrigation water use efficiency is therefore essential to achieving this goal.This study aims to develop a method to optimize irrigation scheduling for winter wheat in this region.[Method]A field experiment was conducted from October 2022 to June 2023 at a winter wheat field in Hengshui City,Hebei Province.Four irrigation schedules were compared:irrigating once(W1),twice(W2),three times(W3),and four times(W4)during the growing season.Experimental data were used to calibrate and validate the AquaCrop model.The calibrated parameters were then applied to optimize irrigation scheduling.[Result]The calibrated AquaCrop model accurately simulated canopy development,above-ground biomass,and soil moisture dynamics.The coefficient of determination(R2),root mean square error(RMSE),normalized RMSE(NRMSE),Nash-Sutcliffe efficiency(EF),and index of agreement(d)between the simulated and measured values all fell within acceptable ranges,with R2＞0.85,RMSE＜4.5,NRMSE＜12,EF＞0.8,and d＞0.9.The average error of the simulated grain yield was higher in 2021 than in 2022.Water use efficiency under the W3 treatment was 1.88 kg/m3 in 2021 and 2.35 kg/m3 in 2022.[Conclusion]Among the four irrigation schedules,W3(irrigating three times)was the most effective in improving both grain yield and water use efficiency for winter wheat in the Hebei Plain.The calibrated AquaCrop model accurately simulated winter wheat growth and can be used to optimize irrigation scheduling and improve irrigation water use efficiency in this region and other areas with similar environments.

Abstract:[Objective]The Gansu Section of the Weihe River Basin plays a critical role in regional water supply and ecological stability.This paper investigates the multi-time scale variations of runoff and their potential changes in the future,aiming to provide a basis for improving management and sustainable use of water resources in the basin.[Method]The analysis was based on monthly runoff data measured from 1956 to 2022 from the hydrological stations at Wushan and Beidao.The Mann-Kendall trend test,the rescaled range(R/S)analysis,along with other statistical methods,were used to analyze intra-annual,inter-annual,and seasonal runoff variations.The CNN-LSTM-Attention hybrid deep learning model was developed to predict future runoff changes.[Result]The annual runoff in the Gansu Section of the river basin showed pronounced seasonal variation,with the majority occurring from July to October.Although the annual runoff distribution was uneven,a gradual shift toward more uniformity was observed from 1956 to 2022.Both annual and seasonal runoff showed a declining trend from 1956 to 2022,with a significant abrupt change observed in the 1980s,after which runoff volumes dropped notably.Multi-scale analysis revealed alternating periods of high and low runoff.Model forecasts suggest that the runoff will continue to decline from 2023 to 2030.[Conclusion]Runoff variability in the Gansu Section of the Weihe River is driven by both climate change and human activities,imposing a challenging outlook for sustainable use of water resources in the region.

Abstract:[Objective]Tiger nut is a cash crop in southern Xinjiang and its production relies on irrigation.This paper presents the results of an experimental study on the effect of irrigation amounts on physiological traits,yield,and water use efficiency of different varieties of tiger nuts.[Method]The experiment studied two varieties:the Henan Round Grain(HY)and the Inner Mongolia Round Grain(NY),each irrigated by 18 mm(W1),27 mm(W2),36 mm(W3),and 45 mm(W4)of water,respectively.In each treatment,we measured the changes in soil water storage,plant height,tiller numbers,photosynthetic traits,yield,water consumption,and water use efficiency of the plants at different growing stages.[Result]Soil water storage and water consumption of both varieties increased with irrigation amount.Compared to W1,W4 increased average soil water storage and water consumption of the plants by 24.84% and 60.57% for the HY,and 18.46% and 55.61% for the NY,respectively.The plant height,tiller numbers,net photosynthesis(Pn),stomatal conductance(Gs),transpiration rate(Tr)and the yield of HY increased with irrigation amount(P＜0.05),peaking in W2 with increases of24.60% ,15.11% ,28.14% ,34.86% ,40.49% and 13.92% compared to W1.Intercellular carbon content(Ci)decreased with increasing irrigation amount.With the increase in irrigation amount,the plant height,tiller numbers,Pn,Gs,Tr,and the yield of NY all increased first followed by a decline;their associated values in W2 were 26.07% ,20.26% ,19.69% ,38.38% ,44.92% and 20.83% higher than those in W1.On average,Ci decreased with irrigation amount,being lowest in W2.Water use efficiency and irrigation water use efficiency of both varieties decreased with irrigation amount.Principal component analysis showed the net photosynthetic rate and water use efficiency can be used as indicators for variety selection.[Conclusion]The optimal irrigation amounts for the varieties HY and NY are 45 mm and 27 mm respectively,which can promote healthy growth,improve yields,and enhance water use efficiency of the plants.

Abstract:The three large irrigation schemes,namely Bojili,Xiaokaihe and Handun irrigation scheme,in Binzhou City of Shandong Province include in the pilot list of digital twin irrigation schemes by the Ministry of Water Resoucres.This paper systemically introduced the overall design structure of digital twin irrigation scheme for the three large irrigation schemes,as well as the construction components and technical approaches for the digital twin irrigation development in the three irrigation schemes,including,data base,vertical monitoring system,canal automation,models,support system and management platform,etc.The construction of the digital twin irrigation schemes in the three large irrigation schemes in Binzhou City is based on the existing information system.The total investment has reach more than 42.8 million RMB Yuan,and the major part of the pilot project has completed and put into use successfully and received good application results.The application of water schedule model could reduce planning time by 60％and saving water by 6％,and canal automation could save labor by 40％.With the further development,updating and application of the digital twin irrigation technology in the three large irrigation schemes,irrigation water management can be further improved by increasing digital,intelligent and precise management,which will contribute to high quality and sustainable development of irrigation schemes.

Abstract:[Objective]Irrigation is the largest water consumer in many regions.Understanding its variation and the underlying determinants is important for improving water management.Taking Jiangxi province as an example,we analyze the variation in its irrigation water usage,as well as the factors that influence the changes.[Method]Based on the information entropy and the balance in water utilization across the province,the logarithmic mean divisia index(LMDI)decomposition method was used to identify the meteorological factors that affect and contribute to irrigation water usage.[Result]The change in agricultural irrigation water consumption in the province is affected mainly by net irrigation water consumption per acre land,effective utilization coefficient of irrigation water,and effective irrigation areas,and actual irrigation ratio.The impact of irrigation water use efficiency negatively affected the change in irrigation water usage,while the impact of other factors varied with other conditions.Correlation analysis showed that the net irrigation water consumption per acre land and its contribution to irrigation water usage are affected mainly by rainfall.Excluding weather-related factors,the change in irrigation water consumption in the province was negative,indicating that the management of irrigation engineering projects has been improved.The increased irrigation water utilization efficiency is the main reason behind the decreased agricultural irrigation water consumption.Five cities in the province,including Shangrao,Fuzhou,Yichun,Jian,and Ganzhou,still have room for implementing water-saving irrigation.[Conclusion]Given the potential growth in the ratio of the effective irrigation areas to actual irrigation areas,the province should take measures by,for example,developing water-saving projects in large and medium-sized irrigation areas and optimizing water resource allocation,to improve effective irrigation water utilization coefficient and alleviate water pressure.

Abstract:[Objective]Subsurface drain is a drainage system widely used in northwestern China to keep the groundwater below the critical depth and facilitate soil salt leaching.This paper presents an experimental study on the combined effect of drain depth and spacing on soil salt leaching in a representative oasis in Yanqi Basin.[Method]The drains were buried at the depth of 1.2 or 1.5 m,with the spacing being 20,30 or 40 m.Overall,there were six treatments.For each treatment,we measured the spatial changes in soil salt contents before and after the leaching,which were then used to analyze the variation in salt leaching efficiency between different treatments.[Result]① When initial soil moisture was at the field capacity,leaching could quickly saturated the soil and displace the water in the soil above the drains.There were no significant correlations between soil moisture content and the depth and spacing of the drains.(2)Salt leaching from the top 0-60 cm soil layer was significantly related to the depth and spacing of the drains.The spacing and depth of the drains combined to affect soil salt removal rate.When the spacing was the same,increasing the burial depth of the drains enhanced salt removal from the 0-60 cm soil layer;when the burial depth of the drains was the same,salt removal rate from the 0-60 cm soil layer was the highest when the spacing was 30 cm(P＜0.05).(3)As the leaching elapsed,both cumulative water drainage and soil salt leaching increased steadily and then tended to flatten;the electrical conductivity of the drainage water was relatively stable,correlating positively to soil salt content.The cumulative water drainage and leached salt were impacted significantly by the burial depth of the drains(P＜0.05)but insignificantly by the drain spacing(P＞0.05).Compared to the burial depth of 1.2 m,the burial depth of 1.5 m considerably improved the drainage efficiency and accelerated soil salt removal.[Conclusion]For maximum soil salt removal rate,the optimal depth and spacing of the subsurface drains for the study area was 1.5 m and 30 m,respectively.