Abstract:[Objective]Maize is a main staple crop cultivated in central and Northern China but it requires irrigation at certain stages during its growth.In this paper,we present the findings of an experimental study on the effect of irrigation amount on photosynthesis and dry matter accumulation of the crop during its tasseling-silking stage.[Method]The field experiment was conducted in the long-term experiment established in 2018 at the experimental base of the academy of agricultural and animal husbandry sciences of Inner Mongolia Autonomous Region.The experiment compared six irrigation amounts:315 m3/hm2(W1),645 m3/hm2(W2),945 m3/hm2(W3),1 275 m3/hm2(W4),and 1 605 m3/hm2(W5);the control was rain-fed(W0).During the experiment,we measured photosynthetic characteristics and dry matter accumulation of the crop in each treatment.The photosynthetic characteristics and its correlation with dry matter accumulation were calculated by fitting the response curve parameters to a non-right-angle hyperbolic model.[Result]The leaf SPAD in W3 was lower only than that in W4 in 2019,but in 2020 it increased by 3.96％,5.12％,11.10％,12.64％and 19.90％,respectively,compared with that in W4,W2,W1,W5 and W0.In 2019 and 2020,the average daily net photosynthetic rate was the highest in W3,while in 2019,the dry weights of stems,leaves and ears in W3 were the second highest among all treatments.In 2020,the physiological indexes of the crop in W3 were higher than that in other treatments.There was no significant difference in leaf photosynthesis between W3,W4 and W5.[Conclusion]In central and western regions of Inner Mongolia,when the total rainfall during growing season of maize exceeded 365 mm,irrigating 945 m3/hm2 of water can effectively improve photosynthetic efficiency of the maize during its tasseling-silking stage,promote dry matter accumulation and increase grain yield.

Abstract:[Objective]Subsurface drip fertigation is an irrigation technique to simultaneously deliver water and dissolved nutrients into the root zone.Its efficacy depends on many factors.In this paper,we investigate the combined effect of phosphate fertilizer types and dripline depth on distribution of nitrogen and phosphorus in soil and grain yield of maize.[Method]The experiments were conducted in tanks grown with maize in a rain shelter,using two types of fertilizers:ammonium polyphosphate(APP,Pl)and monoammonium phosphate(MAP,P2).The control is no fertilization(CK).The driplines were buried at the depths of 0 cm(D1)and 15 cm(D2).In each treatment,we measured the spatial variation of nitrogen and phosphate,as well as grain yield.[Result]Nitrogen applied in the drip fertigation can move to the edge of the maize roots and accumulate there,while the phosphorus was absorbed by soil.The polymerized phosphate fertilizer(P1)weakened soil adsorption and fixation compared to the normal phosphate fertilizer(P2).Soil available phosphorus content in the APP was 15％higher than that in MAP.Irrigation facilitated phosphorus movement in soil and improved uniformity of its distribution,with the bioavailable phosphorus in D2 being 17％higher than in D1.Phosphorus application significantly promoted root growth,with the root length density at the jointing stage being 35％and 19％higher in P1 and P2 than in CK,respectively.It was also found that D2 increased root length density by 12％,compared to D1.Phosphorus application increased bioavailable phosphorus and root length density.This in turn enhanced dry matter accumulation and root uptake of nitrogen and phosphorus,thereby increasing the final grain yield.Pl increased the grain yield by 3％compared to P2,and 21％compared to CK.[Conclusion]Our results showed that subsurface fertigation using APP reduced soil phosphorus adsorption,which in turn promoted maize growth and increased the final grain yield.

Abstract:[Objective]Agriculture is the largest water consumer in Shanxi Province.Understanding the water requirements of major crops is important for improving water resource management and the development of sustainable agriculture in the province.This paper studies the spatiotemporal variations in irrigation water requirements and drought assessment for major crops in the province.[Method]The reference evapotranspiration(ET0)was calculated using the Penman-Monteith formula based on daily meteorological data from 1960 to 2019 at 28 weather stations across the province.Using the single crop coefficient method,we calculated the water requirements(ETc)and irrigation requirements(IR)of spring maize,summer maize,spring wheat,winter wheat,cotton and potato.The spatial distributions of effective precipitation,temperature,ET0,ETc and IR for each crop were analyzed using ArcGIS to evaluate drought frequency and its impacts across the province.[Result]Spatially,ET0 and average daily temperature vary consistently across the province,decreasing from South to North up to Wutai and Youyu,then increasing further northward.Temporally,except for potato,the IR of other crops has been decreasing from 1960 to 2019,with their IR varying spatially.The average IR of major crops over the 1960-2019 period ranked as follows:winter wheat(293.23 mm)>spring wheat(144.74 mm)>spring maize(142.81 mm)>cotton(131.89 mm)>summer maize(82.81 mm)>potato(74.56 mm).During growing periods of crops,the influence of droughts,when occurring,were regional.[Conclusion]Precipitation can basically meet the demands of summer maize,spring maize and spring wheat need for irrigation during their rapid growth periods.However,winter wheat,cotton,and potato require irrigation during their mid-growth periods.

Abstract:[Objective]Cotton is a major economic crop in saline-alkali regions of southern Xinjiang,where soil salinity and water availability affect crop growth and yield.Optimizing irrigation is essential for improving water use efficiency(WUE)and maintaining stable production of cotton in these regions.This paper experimentally studies suitable drip-irrigation strategies for cotton cultivated in saline-alkali soil with plastic film mulch.[Method]A field experiment was conducted from April to August 2018 to evaluate the influence of plant row spacing and irrigation methods on cotton growth.There were four irrigation-amount treatments by irrigating 45,37.5,30 mm and 22.5 mm of water in each irrigation;the irrigation interval was 10 and 7 days.In the experiment,we measured soil water and salt content in the root zone,growth and WUE of the cotton.[Result]During the first 70 days after sowing,water content in the 0-40 cm soil layer decreased with decreasing irrigation amount.At the seedling stage,soil moisture difference between wide and narrow plant row spacing was negligible,while by the bud stage,water content difference in soil below 40 cm between different row spacings became increasingly pronounced.Soil salt content in the top 0-40 cm soil layer showed minimal variation among treatments during the seedling stage,but significant differences emerged after flowering began.Salt content in the 60-100 cm soil layer steadily declined in the first 80 days post-sowing and then stabilized thereafter.Irrigation 45 mm every 10 days during the bud stage followed by 30 mm every 7 days during the flowering stage achieved the highest WUE of 1.42 kg/m3,with a seed cotton yield of(6 916.2±338.6)kg/hm2.Irrigating 45 mm every 10 days during the bud stage and 37.5 mm every 7 days during the flowering stage yielded the highest seed cotton production of(7 703.9±641.9)kg/hm2,with a WUE of 1.37 kg/m3.[Conclusion]For cotton cultivated with drip irrigation under plastic film mulch in saline-alkali soils,the optimal irrigation strategy is irrigating 45 mm every 10 days during the bud stage followed by 37.5 mm every 7 days during the flowering stage.This can effectively balance soil moisture and salinity dynamics,while maximizing water use efficiency and seed cotton yield.

Abstract:[Objective]A pre-planting border irrigation in spring coupled with a drip irrigation in summer during crops growth season is an irrigation technique to reduce soil salinity and safeguard crops growth in the salt-affected soils in the Hetao Irrigation District in Inner Mongolia.This paper investigates the impact of different combinations of irrigation amounts in the dual irrigations on changes in soil water and salt,as well as the growth of sunflower.[Method]The field experiment compared two spring(S)irrigation amounts:95 mm and 135 mm,and three summer(W)irrigation amounts:68,100 mm and 135 mm.In each treatment,we measured the spatiotemporal changes in soil water and salt,as well as crop growth characteristics.[Result]① The soil water content in the S135W135 treatment was the highest among all treatments during the experimental period,with the average soil water content and saturation being 17.10% and 75.53% ,respectively.The coefficient of variation of soil water content in the S95W135 treatment was 22.40% ,the lowest among all treatments.② Depending on the summer irrigation amount,the desalination rate of the 0-80 cm soil layer under S1 35 and S95 varied from 32.64% to 50.50% and 21.8% to 38.87% ,respectively.Although the spring irrigation amounts did not significantly affect immediate post-irrigation salt content,the S135W100 and S95W135 combinations showed deeper leaching depths and higher desalination rates(40.77% and 33.37% ,respectively)than other treatments.③ Aboveground dry matter production was significantly higher in the S95W135 and S135W100 combinations than in other combinations,surpassing the S135W135 combination by 10.55% and 9.94% ,respectively.The S135W100 combination achieved the highest water use efficiency at 21.59% ,an increase of 13.03% compared to S135W135.[Conclusion]Reducing spring irrigation by 30% to 95 mm combined with a summer drip irrigation of 135 mm is the most efficient irrigation scheme for sunflower cultivation in the salt-affected soils in the Hetao Irrigation District.

Abstract:[Objective]The mismatch between water distribution time and water flow rate is an issue in distributing water across canal network systems.This paper proposes an optimal method to allocate water across canal networks in irrigation districts.[Method]The method was based on channel hydrodynamics.The objective of the optimization was to maximize flow water distribution and expedite water allocation.The constraints included channel discharge capacity,water distribution rate and sequence,water balance,bifurcation diversion processes,and channel transmission losses.The optimal water distribution was obtained by solving the one-dimensional hydraulic model for each channel.The model was applied to irrigation districts with four-level of channels.Aligning with water distribution practices in the irrigation districts and for facilitating gate regulation management,the model adopted a top-down irrigation approach.[Result]The optimal method coordinated the timing and flow of water distribution in the main canal,branched canals,lateral canals and field canals well,achieving a well-balanced water distribution in each irrigation event.Compared to traditional water distribution,the proposed method improved the start and end timing of water distribution in each level of the canals;the results were more aligned with the real water supply process.Water flow rate and volume in the canals at the end-level can meet the water demand.[Conclusion]The channel hydraulic-based optimization method we proposed for water distribution can accurately allocate the water over the irrigation area and improve the efficiency of water distribution management.

Abstract:[Objective]Ensuring the ecological security of cropped lands is a prerequisite for developing sustainable agriculture and safeguarding food security,which is influenced by various factors.In this paper,we analyse the spatiotemporal variation in ecological security of cultivated lands and its determinants in key agricultural production regions in Henan Province.[Method]The analysis was based on the pressure-state-response(PSR)model,comprehensive index approach,and resistance diagnosis model.In the analysis,we considered fifteen indicators to assess the changes in ecological security from 2007 to 2022 across the province.[Result]① From 2007 to 2022,the ecological security of cultivated lands in the province initially declined before recovering,with the composite index increasing from 0.342 in 2007 to 0.435 in 2022.② The ecological security of cropped lands varied significantly across the province,with heightened sensitivity in the central areas,general and comparative security in the eastern regions,and high sensitivity in remote areas.③ Key factors affecting the ecological security of cropped land in the province included fertilizer application per unit area(26.1％),cultivated land per capita(18.69％),and per capita water resources(18.45％).[Conclusion]From 2007 to 2022,the ecological security of the cultivated lands in Henan Province has substantially shifted.The overall ecological security of the cropped land in the province is at a moderate level,underscoring the need to improve agricultural resource use efficiency,reduce fertilizer and pesticide application,and foster sustainable interactions between terrestrial ecosystems and food security.Priorities in improving ecological security of the agroecosystems in the province include optimizing fertilizer application and preserving cultivated lands.These findings provide baseline for developing sustainable land management to safeguard food security in the major agricultural production regions in Henan Province.

Abstract:[Objective]Ryegrass(Lolium perenne)is extensively cultivated in Northwestern China for various purposes ranging from forage to landscaping.This paper presents the results of an experimental study on optimal irrigation and nitrogen fertilization for growth and yield of perennial ryegrass in managed grasslands in Yongdeng County in Gansu province,China.[Method]The field experiment consisted of two irrigation treatments by keeping the soil water content above 75%-85%(W1)or 55%-65%(W2)of the field capacity.Each irrigation treatment had three nitrogen treatments by applying 210(N1),180(N2)and 150 kg/hm2(N3)of nitrogen.In each treatment,we measured the growth traits,yield,and water and nitrogen use of the ryegrass at different growth stages.The optimal irrigation and nitrogen fertilization was determined by the entropy-weight TOPSIS model.[Result]Both irrigation and nitrogen significantly influenced ryegrass growth and yield.Increasing irrigation amount or nitrogen application improved growth traits and yield.However,nitrogen partial factor productivity(PFPN)decreased with increase in nitrogen application,and increasing irrigation amount reduced irrigation water use efficiency(IWUE).Nitrogen application had a greater impact on growth and yield of the ryegrass than irrigation.The W1N1 combination resulted in the highest plant height,chlorophyll content,and yield,while W2N1 produced the largest stem diameter.The W1N3 combination had the highest PFPN,and IWUE was greatest in W2N2.Entropy-weight TOPSIS analysis showed that W2N2 was optimal for ryegrass growth and yield in the study area.[Conclusion]Maintaining soil moisture above 55%-65%of the field capacity combined with 180 kg/hm² of nitrogen fertilization is the optimal strategy for improving the growth and yield of perennial ryegrass in Yongdeng County,Gansu Province,China.

Abstract:[Objective]Understanding water utilization across sectors and regions is essential for regional water resource management and sustainable development.The objective of this paper is to evaluate water usage in six provinces in central China,providing insights into sustainable water resource management.[Method]Using an energy-based ecological theory,we calculated the spatiotemporal variation in the ecological carrying capacity of water in the six provinces and analyzed its composition.[Result]① The energy-based water ecological footprint across the six provinces shows a fluctuating upward trend.Surface water contributes the highest ecological carrying capacity(84%),followed by groundwater(9%)and rainwater(7%).② The water ecological surplus index indicates a fluctuating upward trend but reveals an overall water ecological deficit.The ecological pressure index exhibits a fluctuating downward trend,peaking in 2011 and reaching its lowest point in 2016.③ Both the energy-based ecological carrying capacity and ecological footprint demonstrate significant spatial variation,high in the southern provinces compared to the Northern ones.④ Ranking of the water ecological surplus index(largest to smallest)in the six province is as follows:Hubei(2.94×108 hm2),Anhui(2.37×108 hm2),Henan(2.27×108 hm2),Hunan(1.22×108 hm2),Jiangxi(1.06×108 hm2),and Shanxi(0.62×108 hm2).The southern provinces exhibit lower ecological pressure indices compared to the northern provinces.⑤ The composition of water ecological footprints varies significantly between provinces.Agricultural water use is the largest in all six provinces,while ecological and environmental water use is the smallest.In the southern region,water use is dominated by aquatic production,followed by industry water use,domestic use,and water pollution.In contrast,water use in the northern region is dominated by domestic use,industrial use,water pollution,and aquatic production.[Conclusion]The unsustainable use of water resources in central China poses significant challenges to ecological balance.To achieve sustainable water utilization,the region should focus on constructing water conservancy projects,implementing water-saving technologies,and optimizing water use.

Abstract:[Objective]The radar flow meter utilizes electromagnetic waves to measure water velocity,offering an efficient,non-invasive method for water flow measurement.In this paper,we experimentally investigates its feasibility for automatically measuring the cross-section flow in open channels,in attempts to improve water resource allocation and support intelligent,precision-based water-saving irrigation systems.[Method]The velocity-area method was used in the experiment,where the radar velocimeters were installed at the heights of 2.1 m and 4.7 m above the canal bottom on a rigid truss bridge.The equipment automatically measured surface velocity and midstream depth.A mathematical model was developed to calculate the cross-sectional area and flow rate based on these measurements.The calculated flow rates were compared with those obtained from an electromagnetic flowmeter installed in a 600 m outlet pipe,upstream of the section.[Result]Comparison between flow rates measured by the radar flow meter and the electromagnetic flowmeter showed that the flow rate error ranged from 0.014 to 0.026,meeting the requirements for water flow measurement.For the radar velocimeter installed at heights of 2.1 m and 4.7 m over the bottom,their system errors were 0.89%and-0.79%,with the associated random uncertainties being 2.22%and 2.88%,respectively.For full-section precast concrete slab masonry,the measured flow rate error was 0.02.The overall accuracy of the flow measurement system exceeded 95%.[Conclusion]Radar velocity measurement technology satisfies the requirements for open channel flow in in irrigation districts.The developed model can accurately calculate average flow velocity,enables automatic,accurate flow measurements in large open channels.The system is well-suited for precise flow monitoring and management in modern irrigation systems.

Abstract:[Objective]Saline soils in seasonal frozen regions are often used as channel foundations but are prone to frost heave and salt migration,which can compromise structural stability.The objective of this paper is to investigate the efficacy of soil solidification in improving frost resistance and mitigating salt migration,and provide insights for improving engineering design in cold regions.[Method]Freeze-thaw cycle tests were conducted on saline soil with and without solidification in laboratory.There were five test sets,with the compaction coefficient varying from 0.855 to 0.952 and soil moisture content ranging from 10%to 18%.Key parameters,including frost heave force,frost heave volume,and salt migration were measured during the experiment.[Result]① Both solidified and non-solidified saline soils exhibited significant fluctuation in the frost heave force for temperature in the range of-10 to 0℃.Solidification reduced the frost heave force by up to 65.0%compared to non-solidified soil.②Solidification reduced the frost heave volume by 41.8%at the same soil depth,compared with non-solidification.③Salt migration decreased with increasing soil depth in both solidified and non-solidified soils.However,significantly slower migration was observed in solidified soils.④ With the increase in compaction coefficient,the frost heave force,frost heave volume,and salt migration initially increased,followed by a decline,after the increase exceeded a threshold.[Conclusion]Soil solidification significantly improved the frost resistance and reduced salt migration in saline soils.An empirical model was developed to estimate the maximum frost heave force and volume based on compaction coefficient and the number of freeze-thaw cycles,as well as salt migration as a function of soil depth.Our findings suggest that a compaction coefficient in the range of 0.85-0.90 is optimal for small-scale channel foundations,while a compaction coefficient exceeding 0.94 is recommended for medium to large-sized channels.

Abstract:[Objective]Gansu Province,with its unique geographic and climatic conditions,faces significant challenges in sustainable use of its soil and water resources.This paper analyzes the spatiotemporal variation interaction of soil and water resource carrying capacities in the province,with the aim of informing improved resource management and promoting sustainable development.[Method]Data on soil and water resources from 2000 to 2022 were used to assess their spatiotemporal variation and coupling coordination at the municipal and prefectural levels.The ecological footprint model and the coupling coordination degree model were applied for quantitative analysis.[Result]① Temporally,the per capita ecological footprint and carrying capacity of water resources in the province fluctuated significantly over the study period.The highest per capita water ecological footprint was 0.789 hm2 in 2004,and the lowest was 0.687 hm2 in 2019.Spatially,water resource footprints were generally higher in the northwest and lower in the southeast.② For land resources,the per capita ecological footprint and carrying capacity first declined and then gradually increased over time.Spatially,the pattern mirrored that of water resources,with higher footprints in the northwest and lower footprints in the southeast.③ The coupling degree between the per capita ecological footprint and the carrying capacities of soil and water resources showed a steady increase,ranging from 0.5 to 0.9.This indicates a transition from weak to moderate and strong coordination levels.[Conclusion]Enhancing the integrated management of soil and water resources,along with the implementation of region-specific protection strategies,is essential for improving carrying capacity and ensuring the sustainable use of soil and water resources in Gansu Province.

Abstract:[Background]Agricultural production in Northern China faces two major challenges:water scarcity and low fertilizer efficiency.Improving management practices to enhance water and nitrogen use efficiency is therefore crucial for developing sustainable agriculture in this region.This study investigates how biochar application,irrigation,and nitrogen fertilization can be optimized to improve crop growth and yield.[Method]A field experiment using a three-factor,three-level orthogonal design was conducted in a winter wheat field from 2021 to 2022.The experiment included three biochar application rates(0,12.5,and 25 t/hm2),three irrigation treatments(75%,100%,and 125%of evapotranspiration),and three nitrogen application levels(120,180,and 240 kg/hm2).During the experiment,we measured grain yield,water use efficiency(WUE),and nitrogen use efficiency(NUE)of the crop.[Result]Biochar application had an insignificant effect on water consumption,nitrogen accumulation,grain yield,WUE,and NUE.Irrigation levels did not significantly affect grain yield;however,increasing irrigation increased water consumption and decreased WUE,though these effects were not statistically significant.Increasing nitrogen fertilization significantly enhanced grain yield and nitrogen accumulation but reduced NUE.Statistical analysis indicated that nitrogen application was the primary factor affecting grain yield,nitrogen accumulation,and NUE,whereas irrigation and biochar application had no significant impact on these traits.[Conclusion]Irrigating at 75%of evapotranspiration did not reduce grain yield and resulted in the highest WUE.Due to high precipitation during the experiment,however,the optimal management strategy for winter wheat under drip irrigation in this study was 0 t/hm2 of biochar,100%of evapotranspiration for irrigation,and 240 kg/hm2 of nitrogen fertilization.

Abstract:[Objective]Soil organic carbon(SOC)is not only an indicator of soil health but also plays a crucial role in feedback interaction between global warming and carbon stock in terrestrial ecosystems.Its dynamics is modulated by a multitude of interactive abiotic and biotic factors.In this paper,we analyze the spatial distribution of SOC in the plough layer and its correlation with soil texture and other geochemical properties in the region of Zhengzhou in Henan province.[Method]Soil samples were taken from a grid network in the region.SOC,bulk density,soil texture and other geochemical properties in each soil sample were measured.The correlation between SOC and soil nutrients,including nitrogen,phosphorus,potassium and micronutrients in the soil,was analyzed using the GeoChemStudio software.[Result]The calcareous skeletol soil in the region has the highest SOC,reaching 2.307% .The SOC content varied from 0.1% -1 1.6% across the region,and was normally distributed with a mean of 1.134% .The SOC was positively correlated with N,P2O5,Fe,Mn,Zn,Cu,Mo and B,and their associated correlation coefficients were 0.804 5,0.223 0,0.156 3,0.119 1,0.223 8,0.263 4,0.162 8 and 0.191 1,respectively.Negative correlations were found between SOC and K2O and pH,and their associated correlation coefficients were-0.088 8 and-0.195 7,respectively.The average SOC content in the plough layer in the region was 1.09% .Spatially,SOC was rich in Xinmi,Dengfeng and Gongyi in the southwest of the region.In terms of soil texture,SOC is higher in skeletol soil and calcareous cinnamon soil than in other soils.SOC stored in the topsoil in the whole region was 1 012.87×104t,with 523.13x 104t stored in the cinnamon soils and calcareous cinnamon soils,accounting for 51.64% of the total topsoil SOC in the region.

Abstract:[Objective]Crops are vulnerable to drought and waterlogging at their seedling stages.Experience-based irrigation and drainage is not effective to alleviate water stresses that seedlings could face.This paper presents an automatic drainage and irrigation system we developed for seedlings of direct-seeded rice.[Method]The system includes a micro-sprinkler irrigation system and an automatic drainage device.They are controlled by a LoRa wireless communication network;the irrigation-drainage scheduling was calculated by the fuzzy control algorithm,based on the dynamics of soil moisture and growth of the seedlings measured in the field.The applicability of the system in the fields was evaluated using performance indicators and drainage device performance indicators.[Result]① In the terms of performance,the delay in the response of the system was 0.398 s,the decision-making time was 1.348 s,and the errors of the information monitoring was±1.48％.② The automatic drainage device took 4-6 s to close or open,and the standby electric current was 21.7 mA.③ Experimental results showed that the systems can control soil moisture at 85％of the field capacity 15 days after the seed-drilling;the survival rate of the seedlings was 83.9％.[Conclusion]The automatic irrigation and drainage system for seedlings of direct-drilled rice is energy-efficient.It can maintain soil moisture in the proximity of the soil surface around the designed value,alleviating water stress and improving the survival of the seedlings of the directly drilled rice.

Abstract:[Objective]The Barkol Lake Basin is located in the east of Xinjiang of China,and groundwater plays a pivotal role in supporting agriculture,livestock and other sectors in the region.This study aims to analyze the chemical characteristics and health risks associated with groundwater in the plain areas in the basin.[Method]The analysis utilized groundwater quality data collected in August 2022.Factors influencing groundwater chemistry were evaluated using ion ratio and saturation index methods.Groundwater quality and the associated health risks were assessed with the entropy weight water quality index method and a health risk assessment model.[Result]The groundwater in the study area is weakly alkaline,with low salinity and moderate hardness.Its hydrochemical profile is primarily of the HCO3·SO4-Ca·Na type.The chemical properties are predominantly influenced by rock weathering and cation exchange.In the region,75.0％of the groundwater is deemed drinkable without treatment,8.3％is of moderate quality,and 16.7％is undrinkable without further treatment.The non-carcinogenic health risk index for Na+is the highest,with children facing a greater potential non-carcinogenic risk compared to adults.[Conclusion]Overall,groundwater quality in the area is satisfactory,though there are potential risks in the northern part of Bolqiangji Town.This analysis provides a baseline for ensuring the safe use of groundwater in the region.

Abstract:[Objective]The cultivation of soybeans has increased in China and to assess the potential influence of this on agricultural water usage,we analysed the spatiotemporal variation in its water requirements across the whole country.[Method]The analysis was based on meteorological data measured from 1971 to 2020 in main soybean production regions.Water requirement of soybean in each region was calculated using crop coefficient and the potential evapotranspiration.The Mann-Kendall trend test method and the rescaled range method were used to analyze spatiotemporal variation in water requirement and water deficit of the soybean,for both current conditions and projected future scenarios.[Result]The average water requirement and water deficit of soybeans during their growth period across the country were 382 mm and 111 mm,respectively.However,these values exhibited significant spatial variability.The arid and semi-arid areas in the North,as well as the Qinghai-Tibet Plateau and the Loess Plateau are particularly susceptible to drought and water shortage.The average water deficit across various regions in the country ranged from 30 mm to 344 mm.Drought and water shortage have been worsening in some regions,which include the Eastern arid and semi-arid regions in Northern China,the Southern Northeast plain,the Western Huang-Huai-Hai plain,the Southern Yunnan-Guizhou plateau,the Southern region in the Northeast plain,the Western Huang-Huai-Hai plain,the Southern Yunnan-Guizhou plateau,specially in the Southern Yunnan-Kweichow Plateau.Furthermore,drought and water shortages in the Eastern arid and semi-arid regions in Northern China,the Southwest of the Yunnan-Guizhou plateau,and the Western Qinghai-Tibet Plateau are expected to Worsen.A potential water shortage crisis is anticipated in the Western Huang-Huai-Hai region,the Southeast of the Yunnan-Guizhou plateau,and the Northern,middle and lower reaches of the Yangtze River.[Conclusion]Our analysis indicates that drought and water shortage for soybean production in the South of the Northeast Plain,Western Huang-Huai-Hai Plain,and the middle and lower reaches of the Yangtze River are predicted to intensify.Therefore,enhancing water-saving measures is essential for sustaining water resource use in these regions for soybean production.

Abstract:[Objective]Spring wheat is an important cereal crop in Northern Xinjiang,where limited precipitation during the growing season makes irrigation essential for its successful production.This paper investigates the effect of irrigation amount on its growth traits and final yield,in attempts to identify an optimal irrigation schedule for spring wheat in this region.[Method]The field plot experiments were conducted using the high-yielding varieties'Xinchun 37'and'Xinchun 44'.Each variety was subjected to four irrigation treatments:4 500 m3/hm2(W1,resulting in severe drought),5 250 m3/hm2(W2,resulting in moderate drought),6 000 m3/hm2(W3,normal irrigation),and 6 750 m3/hm2(W4,excessive irrigation).For each irrigation treatment,we measured the growth traits,water use efficiency,and grain yield of the two crops.[Result]Soil water content in the 0-60 cm layer increased with the irrigation amount,with water in the 0-20 cm soil layer showing the most significant fluctuation.With the increase in irrigation amount,plant height and dry matter accumulation of both varieties increased initially,followed by a decline.It was also found that the grain-filling period of Xinchun 37 was longer than that of Xinchun 44.Compared to W4,W3 increased the water use efficiency of Xinchun 37 and Xinchun 44 by 30.00％and 15.45％,respectively,the irrigation water use efficiency by 33.91％and 19.85％,respectively.Compared to all other treatments,W3 increased the grain yield of Xinchun 37 by 14.45％-38.24％,while compared to W1 and W2,it increased the grain yield of Xinchun 44 by 25.76％and 14.45％,respectively.[Conclusion]Regression analysis shows that the optimal irrigation amount for Xinchun 37 and Xinchun 44 was 5 875.83 m3/hm2 and 5 967.67 m3/hm2,respectively,in the studied region.

Abstract:[Objective]The baffle plates in the forebay of lateral inlet pump stations are critical components to control water flow and optimize the performance of the pump station.We proposed a method to optimize their design.[Method]We used computational fluid dynamics(CFD)combined with the backpropagation neural network-genetic algorithm(BPNN-GA)to optimize the design parameters of the rectification baffle plates in the forebay.The optimization process used a comprehensive evaluation index,F,which calculated the fitness of the genetic algorithm based on the uniformity of the axial flow velocity distribution and the velocity-weighted average angle.The BPNN model was fine-tuned,with the comprehensive index F as the optimization objective,leading to the identification of optimal design parameters for the rectification baffle plates.[Result]The optimization results showed that the rectification baffle plates designed by the BPNN-GA algorithm significantly improved the flow pattern within the inlet channel.Notable improvements included increased uniformity in axial velocity distribution and a better velocity-weighted average angle.Additionally,the improved design also significantly reduced the vortex area within the forebay,with the comprehensive evaluation index F showing a 6.31 reduction.[Conclusion]The proposed BPNN-GA algorithm for optimizing the design parameters of the rectification baffle plates effectively ameliorated the undesirable flow conditions in the forebay.It provides a valuable method for improving the design of similar hydraulic structures.

Abstract:[Objective]Jujube is a vital cash crop in Xinjiang.This study examined the combined effect of irrigation and potassium fertilization on physiological traits of jujube leaves and fruit yield to determine the optimal irrigation and fertilisation strategy for its sustainable production in this region.[Method]The field experiment was conducted from 2022 to 2023 in an 8-year grey jujube orchard in Aksu,Southern Xinjiang.There were three irrigation treatments by irrigating 100%(T1),75%(T2)and 50%(T3)of estimated evapotranspiration.Each irrigation treatment had three potassium fertilizations:240 kg/hm2(A),180 kg/hm2(B)and 120 kg/hm2(C).During the experiment,we measured the photosynthetic traits of the jujube leaves and ultimate fruit yield.[Result]Both irrigation amount and potassium fertilization significantly impacted growth and development of the jujube.The net photosynthetic rate,transpiration rate and chlorophyll content of the jujube increased with increasing irrigation amount and potassium fertilization.Increasing potassium fertilization increased soluble sugar in jujube leaves,with its content in T1-A,T2-A and T3-A in 2023 increasing by 37.0%,36.9%and 28.7%,respectively,compared to that in 2022.The abscisic acid(ABA)in jujube leaves varied with irrigation amount,being the highest in T3-C.The irrigation water use efficiency increased as the plant grew,and the fruit yield increased with the increase in potassium fertilization.When potassium application was 240 kg/hm2,T1 and T2 increased the fruit yield by 56.77%and 45.52%in 2022,and 51.46%and 37.61%in 2023,compared to T3.Water use efficiency of T2-A was 8.88 kg/(hm2·mm)and 9.14 kg/(hm2·mm)in 2022 and 2023,respectively.[Conclusion]Among all treatments we compared,irrigating 75%of estimated evapotranspiration combined with a 240 kg/hm2 of potassium fertilization is optimal for improving fruit yield and water use efficiency of jujube in Southern Xinjiang.