Abstract:[Objective]Panax Notoginseng is a medicinal herb and primarily grown in Southern China.This paper investigates the impact of irrigation and fertilization on soil potassium and pH,as well as yield and quality of Panax Notoginseng.[Method]The experiment was conducted in Dalishu Village,Luxi County,located in the Honghe Hani and Yi Autonomous Prefecture,Yunnan Province.It consisted of four fertilizations by applying the 480 kg/hm2 of fertilizers at different ratios in the seedling,flowering,fruiting and root gain stages:25％∶25％∶25％∶25％(F1),25％∶30％∶20％∶25％(F2),30％∶30％∶15％∶25％(F3),and 40％∶20％∶10％∶30％(F4).Each fertilization had three irrigation treatments:200 m3/hm2(W1),300 m3/hm2(W2)and 400 m3/hm2(W3).The control(CK)was F1 combined with 92 m3/hm2 of irrigation.In each treatment,we measured the changes in soil potassium content and pH.The technique for order preference by similarity to ideal solution(TOPSIS)was used to evaluate all treatments.[Result]① When irrigation and fertilization were the same,soil pH decreased with soil depth and tended to stabilize as the crop grew.The soil pH showed little sensitive to fertilization.When irrigation was the same,the average soil pH was lower in the four treatments than in the CK.During the experimental period,pH of the 0-60 cm soil in different treatments varied from 4.80-8.66.W3F1,W2F4 and W2F3 gave the optimal soil pH for the crop to grow.② Both total and available soil potassium decreased with increasing soil depth.As the crop grew,the total potassium in the 0-60 cm soil layer increased,while the available potassium decreased initially before increasing.With increasing irrigation amount,total soil potassium decreased,while the available potassium increased initially followed by a decline.Fertilization influenced the dynamics of total and available potassium.Irrespective of fertilization and irrigation,potassium uptake by roots in different growing stages was ranked as follows:fruiting period＞flowering period＞root weight gain period＞seedling stage.Of all the treatments,W2F3 was optimal for soil potassium,with total and available potassium being 10.40 g/kg and 56.69 mg/kg,respectively.③ Regardless of fertilization,with the increase in irrigation amount,the yield and partial factor productivity(PFP)of the crop increased first followed by a decline.The yield,water use efficiency and PFP varied with fertilization.TOPSIS analysis showed that the optimal irrigation was 300 m3/hm2 and the optimal fertilization was applying 144,144,72 kg/hm2 and 120 kg/hm2 of fertilizers in the seedling,flowering,fruiting and root weight gain stage,respectively.[Conclusion]Based on soil potassium,pH,as well as yield and quality of Panax Notoginseng,the optimal irrigation and fertilization for Panax Notoginseng production in the studied area were irrigating 300 m3/hm2 and applying 144,144,72 kg/hm2 and 120 kg/hm2 of fertilizers in the seedling,flowering,fruiting and root weight gain stage,respectively.

Abstract:[Background and Objective]Cadmium contamination is a ubiquitous soil environmental problem facing agricultural production in many countries.Phytoremediation is an environmentally friendly technique.Since bioavailability of Cd varies with biogeochemical environment which,in turn,is regulated by soil water,irrigation is likely to have an important influence on efficacy of phytoremediation.This paper presents the results of an experimental study on the effect of irrigation with saline water on phytoremediation of Cd-contaminated soil.[Method]Pots filled with soil containing Cd at content of 0,5,10 and 15 mg/kg were used in the experiment.All pots were grown with maize and were irrigated with deionized water(W1),natural saline water(W2),and water with NaCl at the same salinity as W2(W3).In each treatment,we measured Cd absorption by the maize.[Result]① When the soil Cd content was low,irrigation with saline water resulted in a reduction in plant height,root length,as well as in dry and fresh biomasses of both above and below-ground parts.However,an increase in soil Cd content significantly inhibited maize plant growth only in treatment W1,while no significant effects were observed in treatments W2 and W3.② When Cd content was 5,10,or 15 mg/kg,the impact of irrigation water on Cd content in the above-and below-ground parts of the maize seedlings was ranked in the order of W3＞W2＞W1.③ When soil Cd content was 5 and 10 mg/kg,Cd accumulation in the above-ground parts of the maize seedlings was significantly lower in W2 and W3 than in W1(P＜0.05),while when soil Cd content was 15 mg/kg,there were no significant differences in Cd accumulation in the above-ground parts of the maize between the three water treatments(P＞0.05).When soil Cd content was 5,10 or 15 mg/kg,there was no significant difference in Cd accumulation in the roots of the maize between the three water treatments(P＞0.05).[Conclusion]Irrigating maize with saline water reduces phytoremediation efficiency of Cd-contaminated soil when soil Cd content was low,while it had no noticeable impact when soil Cd content was high.Saline water can thus be used for phytoremediation of soils heavily contaminated by Cd in areas where freshwater is scarce.

Abstract:[Objective]Maize is a water-intensive crop,and its production in northwestern China heavily depends on irrigation.Optimising irrigation scheduling is hence essential to improving water use efficiency and conserving water resources.This paper proposes a method to optimise irrigation scheduling for maize cultivation in this region.[Method]Field experiments were conducted in Xinjiang using mulched drip irrigation and high-yield maize varieties(DH618 and XY335)under varying total irrigation amounts.For each irrigation-amount treatment,the experiments evaluated the suitable depth of the wetting soil layer,water consumption,yield,and water use efficiency of the crops during different growth stages.The optimal irrigation amount and scheduling were determined based on these measurements.[Result]For both varieties,the suitable depth of the wetting soil layer was 20 cm at early vegetative growth stage,and 40 cm at late vegetative growth stage,tasseling stage and milk stage.The water use efficiency of both varieties was the highest when total irrigation amount was 660 cm.The optimal irrigation scheduling for the DH618 variety was 51-70 mm in each irrigation with the total irrigation amount being 649.5 mm,while for the XY335 variety,the optimal irrigation was 39-67.5 mm in each irrigation with the total irrigation amount being 629.5 mm.[Conclusion]The proposed method,based on soil moisture thresholds and crop water consumption,provides a more scientifically grounded approach to allocate irrigation water across growth stages.It enhances water use efficiency,conserves water resources,and increases maize yield,offering a valuable strategy for sustainable irrigation management in arid regions.

Abstract:Hydrological series are influenced by climate change,ecological succession,and human activities,containing complex,multi-layered,and interactive information that reflects highly non-linear and non-stationary characteristics.Effectively extracting and analyzing hidden information,while understanding temporal variation in hydrological data,remains a challenge.Empirical Mode Decomposition(EMD)has garnered increasing attention due to its ability to analyze non-linear and non-stationary data.This paper reviews the theory and application of EMD in hydrology,including its advantages and limitations.The review explores extensions and adaptations of EMD aimed at improving hydrological sequence analysis.We provide a comprehensive overview of the fundamental theory,methodological characteristics,and current challenges of EMD,covering five EMD-based methods:Hilbert-Huang Transform(HHT),Ensemble Empirical Mode Decomposition(EEMD),Multivariate Empirical Mode Decomposition(MEMD),Extreme Point Symmetric Mode Decomposition(ESMD),and Variational Mode Decomposition(VMD).The pros and cons of each method are analyzed.Additionally,we review the progress of EMD and its variants,particularly in the context of multi-spatiotemporal scale analysis,trend detection,and predictive modeling of hydrological series.Key insights are drawn from the use of EMD in detecting trends,identifying temporal variation features,and improving model predictions for hydrological data across different spatial and temporal scales.Despite the advancements in application of EMD and its variants in hydrology,challenges remain,including issues related to method robustness and efficiency in handling large-scale datasets.We conclude by offering recommendations for future research,including advancing EMD theory and enhancing techniques for analyzing hydrological variability at multi-temporal and multi-spatial scales under changing environmental conditions.

Abstract:[Objective]Leaf water potential(LWP)is a key physiological trait reflecting plant responses to environmental conditions.However,large-scale field measurements remain challenging.This study explores the feasibility of using spectral imaging for indirect LWP estimation.[Method]A field experiment with a soil water gradient was conducted in a potato field in Wuchuan County and Chahar Right Front Banner,Inner Mongolia.Leaf spectral reflectance and water potential were measured at different growth stages.Moisture-sensitive spectral bands were analyzed,and the optimal combination of difference,ratio,and normalized difference spectral indices was identified within the 350-2 500 nm wavelength range.[Result]The selection of optimal sensitive bands varied across growth stages and significantly impacted estimation accuracy.For individual growth stages,the most sensitive bands were primarily located in the red-edge and near-infrared regions,while for combined growth stages,the most effective bands were predominantly in the near-infrared region.A strong linear correlation was observed between the optimized spectral index and LWP.The Optimized Normalized Difference Spectral Index(NDSI)was the most effective index for estimating potato LWP at a single growth stage.As growth progressed,the correlation between spectral indices and LWP improved,with the highest estimation accuracy and robustness observed during the starch accumulation stage.At this stage,the coefficient of determination(R2)for training data reached 0.90,with an RMSE of 0.07 MPa and an MRE of 6.70%,while for validation data,R2 was 0.87,RMSE was 0.08 MPa,and MRE was 7.41%.When multiple growth stages were combined,the optimized spectral index enhanced LWP estimation accuracy during the tuber formation and expansion stage.For these stages,the R2 values for training and validation data were 0.64 and 0.53,respectively,with RMSE values of 0.14 MPa and 0.16 MPa,and MRE values of 10.39%and 12.40%.Compared to existing moisture-sensitive spectral indices,the optimized spectral index significantly improved accuracy and stability across combined growth stages.[Conclusion]The newly developed spectral index,based on band optimization,enhances sensitivity and reduces data dispersion compared to existing spectral indices.It significantly improves the stability of the potato LWP estimation model,offering valuable insights for optimizing spectral indices in potato water status monitoring and precision irrigation management.

Abstract:[Objective]Red soil in Southern China is typically deficient in structure and nutrients.Amending it with straw has been proposed as a method to improve its structure and fertility.This study experimentally examines the effects of different straw incorporation methods on the physicochemical properties of red soil,as well as nutrient leaching.[Method]The experiment was conducted using columns,where soils were repacked into columns and amended with crushed straw,straw powder,or straw ash.The control was soil without amendment.The columns were then subjected to leaching.At the end of the experiment,the physicochemical properties of the soil in each column were measured.[Result]Regardless of the type of straw,amending the soil with it reduced bulk density,increased total porosity and capillary porosity,enhanced soil organic matter,and increased most nutrients,while reducing nutrient leaching.Amending soil with crushed straw was most effective in increasing capillary porosity and reducing nitrate(NO3--N)leaching,as well as minimizing the losses of ammonium(NH4+-N)and total nitrogen(N).In contrast,amending the soil with straw powder was most effective in increasing soil ammonia nitrogen and available potassium content,while reducing the losses of total nitrogen and total phosphorus,and improving the stability of soil aggregates.Amending the soil with straw ash was most effective in increasing total soil porosity,soil organic matter,available phosphorus,and reducing total losses of nitrate(NO3--N),total phosphorus(P),and ammonium(NH4+-N).However,producing straw ash is environmentally unfriendly.[Conclusion]Among the three types of straw,amending soil with straw powder was the most effective in improving soil structure and the physicochemical properties of red soil.This method can be used as an improved agronomic technology to enhance the productivity of red soils.

Abstract:[Objective]The Hetao Irrigation District,the largest irrigation district in Inner Mongolia,relies primarily on water diverted from the Yellow River.However,long-term irrigation has led to increasing soil salinization.This study aims to analyze the spatiotemporal variations in drainage volume and mineralization within the district to inform sustainable drainage water reuse strategies.[Method]The analysis was based on drainage water and its mineralization measure from 2006 to 2020 in the irrigation district.The Mann-Kendall trend test was applied to assess the spatiotemporal variations in both drainage volume and mineralization across three irrigation areas:Jiefangzha,Yongji,and Yichang.Additionally,the Spearman correlation coefficient was used to evaluate the relationship between annual drainage volume and mineralization in each area.[Result]From 2006 to 2020,all three irrigation areas exhibited a significant increasing trend in drainage volume.Mineralization levels remained stable in the Jiefangzha area,while both Yongji and Yichang area experienced a significant decrease in mineralization.The Spearman correlation coefficients between annual drainage volume and mineralization were-0.02 for Jiefangzha and-0.81 for both Yongji and Yichang,indicating a strong negative correlation of drainage volume and mineralization in the latter two areas.Monthly data further revealed significant variations in drainage volume and mineralization,generally displaying a negative correlation.Spatially,the highest average annual drainage volume was recorded in Yichang(2.492 hundred million m3),followed by Jiefangzha(1.897 hundred million m3)and Yongji(1.305 hundred million m3).Notably,before 2014,mineralization levels in Yongji and Yichang were higher than those in Jiefangzha;however,this trend reversed after 2014.[Conclusion]Effective reuse of drainage water in the Hetao Irrigation District requires a comprehensive evaluation of both drainage volume and mineralization.Region-specific strategies that consider crop salt tolerance and local soil properties are essential for optimizing the sustainable utilization of drainage resources.

Abstract:[Objective]Saline-alkali soils pose significant challenges to agriculture in the Western Liaohe Plain of Inner Mongolia.This paper experimentally evaluates the effects of different fertilizations on soil quality and crop yield in theses saline-alkali soils.[Method]A field experiment was conducted in a sunflower field on a saline-alkali soil,and it consisted of five fertilization treatments:no fertilization(CK),conventional fertilization(CF),reducing nitrogen fertilizer by 30％(OF1),reducing nitrogen fertilizer by 30％coupled with replacing 50％of chemical fertilizer with organic fertilizer(OF2),combined OF2 with addition of desulfurized gypsum(OF3).During the experiment,we measured crop yield,soil nutrients,and salinity-alkalinity in the 0-60 cm of soil profile.[Result]Treatment OF3 significantly reduced soil pH and alkalinity in the 0-20 cm topsoil layer,decreasing pH by 0.64 and 0.63 units compared to CK and CF,respectively,and reducing alkalinity by 31.26％and 32.36％.Treatment OF2 decreased salt content in the topsoil by 6.98％and 9.09％relative to CK and CF.The average desalination rate in the topsoil exceeded 17％.Compared to CK,OF2 increased soil organic matter,total nitrogen,available phosphorus,and available potassium by 13.71％,18.55％,23.67％,and 19.76％,respectively;OF3 further increased these parameters by 14.68％,16.49％,34.61％,and 37.65％.Grain yield was improved by 68.21％and 84.85％in OF2 and OF3 treatments,respectively,relative to CK.Principal component analysis ranked the treatment effects on soil properties,nutrients,and crop yield as OF3＞OF2＞CF＞OF1＞CK.[Conclusion]Reducing nitrogen fertilization and substituting part of chemical fertilizers with organic fertilizers,combined with desulfurized gypsum addition,effectively improved soil fertility,mitigated salinization and alkalization,and enhanced crop yields in the saline-alkali soils on the Western Liaohe Plain.

Abstract:[Objective]Understanding the variation in hydrological and sedimentary processes and the underlying mechanisms is essential for integrated watershed management,particularly in arid inland basins.As a major tributary of the Shule River,the Dang River plays a key role in water resource regulation in the Hexi Corridor.This study analyzes the long-term changes in runoff and sediment load in the upper reach of the Dang River and its underlying mechanisms.[Method]The analysis was based on precipitation,runoff,temperature and sediment transport measured from 1972 to 2022.The variations in hydrological and sediment transport were examined using the Mann-Kendall trend test,the cumulative anomaly analysis,and the double mass curve method.A quantitative attribution analysis was used to assess the influence of climate change and anthropogenic activities.[Result]① Runoff and sediment transport showed strong seasonal variation,with their peaks occurring in July and August,primarily during spring and summer.② Over the 50-year period,runoff displayed a significant increasing trend(Hurst index＞0.5),while sediment load exhibited a decreasing but statistically insignificant trend.Abrupt changes were identified in 1986 for runoff and 2007 for sediment.Runoff exhibited dominant cycles of 12,5,8,and 22 years,whereas sediment dynamics were governed by cycles of 30,14,8,and 5 years.③ Attribution analysis revealed that precipitation had a stronger influence on hydrological changes during Transition Period Ⅰ than during Transition Period Ⅱ.In Period Ⅱ,precipitation contributed 196.34％to runoff variation and 65.96％to sediment change,while human activities accounted for 96.34％and 34.04％,respectively,to these variations,mainly through water regulation measures.[Conclusion]Rising temperatures have significantly contributed to increased runoff,while precipitation remains the dominant climatic driver of sediment variation.Human interventions,such as water regulation,have had a beneficial impact on improving water-sediment relationship in the basin.

Abstract:[Background]Sprinkler irrigation is a widely used technique across various sectors.This study examines the impact of using aquaculture water for irrigation on the hydraulic performance of the 20PY2H impact sprinkler systems.[Method]The experiments were conducted under varying working pressures and nozzle spacings,with clean water irrigation serving as the control.Measurements in the experiments included the pressure-flow relationship and water-droplet distribution around the nozzle for each treatment.The relationships between irrigation water type,working pressure,and nozzle spacing were analyzed,along with the influence of meteorological factors on irrigation uniformity.[Result]① Compared with the control using clean water for irrigation,irrigation using aquaculture water reduced flow rate of the sprinkler system by 2.06% -5.3 8% .② When working pressure was in the range of 200-300 kPa and nozzle-spacing was in the range of 1.0-1.4 of the radius of the covered area of the nozzle,the value of the CU calculated by our proposed model varied from 0.74 to 0.88,close to the measured CU which was in the range of 0.66 to 0.79.The erratic change in meteorological conditions in the field could reduce irrigation uniformity by 6.28% -12.78% .[Conclusion]Using aquaculture water for irrigation decreases the flow rate of the sprinkler systems.The effect of working pressure and nozzle spacing on irrigation uniformity is more pronounced when using clean water than using aquaculture water.

Abstract:[Objective]Micro-pressure filters are important components in micro-drip irrigation systems and their performance depends on many factors.In this paper,we study the impact of the distributor and water flow rate on water flow field within the filters.[Method]The study was based on numerical analysis.We used the software Fluent to simulate water flow in the filters under flow rates ranging from 5 to 17 m3/h,both with or without the water distributor.[Result]The standard k-e turbulence model and the Volume of Fluid(VOF)model effectively simulated water flow fields within the filters.Without the water distributor,a dead water zone developed on either side of the front end of the filter screen,with its extent expanded as the flow rate increased.The maximum velocity was at the centre of the inlet connecting pipe,creating a velocity gradient shaped like an inverted cone within the filter screen.A high-pressure zone was developed at the bottom of the filter chamber,with its area decreasing with increasing flow rate.Adding a water distributor increased head loss,generated vortices,and reduced the dead water area.While the distribution of maximum water flow and pressure with and without the distributor was comparable,the distributor mitigated the influence of flow rate on velocity and pressure distributions in the filters.[Conclusion]The overall distribution patterns of velocity and pressure in the filters remained consistent across different flow rates.Adding a water distributor enhanced the flow field,improved filter screen use,and increased the efficiency of water inlet and outlet.These findings provide valuable insights for future research on optimizing water flow and improving the structural design of micro-pressure filters.

Abstract:[Objective]Subsurface seepage pipe assisted with vacuum negative pressure is an emerging technology aimed at regulating soils water dynamics.In this paper,we examine the effects of negative-pressure seepage pipe(NPSP)on soil salt leaching.[Method]We used the HYDRUS model to simulate salt leaching in soils with five soil textures:silty clay,clay,clay loam,sandy clay loam,and sandy loam.Five infiltration water heads(2,4,6,8 and 10 cm)and five negative pressure heads(200,500,1 000,1 500 and 2 000 cm)in the subsurface pipes were considered in the simulations.Based on the simulated results,we calculated the changes in soil salt content before and after a leaching event,as well as the salt leaching efficiency(salt leached per unit of irrigation water).[Result]① Water discharged by the NPSP was primarily originated from the wetting zone in soil profile formed during the infiltration process,and the maximum pipe discharge was obtained as the wetting zone was saturated.② Soil texture was a key factor in influencing water and salt discharge,with both the desalination rate and salt leaching efficiency increasing as sand content increased.③ For all the tested soil textures,the desalination rate was positively correlated with both the surface infiltration head and the inner-pipe negative pressure.However,for sandy clay loam and sandy loam soils,increasing the infiltration head lead to a lower salt leaching efficiency.④ As compared with no-pipe control,the maximum increase of the desalination rate under the application of NPSP was 7.91％,while increased desalination rate were obtained in the soil profile above the NPSP,and the values decreasing with the lateral distance away from the NPSP;There was a salt accumulation zone directly below the NPSP,and its region expanded with the decrease of the applied negative pressure.[Conclusion]NPSP is feasible to facilitate soil desalination without increase the water consumption for leaching practice,and the desalination performance of NPSP is likely be improved in field with sandy soil.

Abstract:[Objective]The Yellow River Basin,the second largest in China,plays a crucial role in food production in the country.In this paper,we analyze the spatiotemporal variations in agricultural water use efficiency and calculate water resource flow patterns and their optimal allocation at watershed scale in the basin.[Method]Using the SWAT model,the basin was divided into sub-basin units to calculate crop water footprints.Virtual water flows were analyzed using social equity principles and the gravitational force method.[Result]In 2020,the total crop water footprint in the basin was 76.91 billion m3,with green water accounting for 69.7%.The middle reaches contributed the largest to the total water footprint,significantly surpassing upstream and downstream regions.Both blue and green water footprints exhibited seasonal variation,peaking between May and August.The average water footprint for crop production was 0.72 m3/kg,with notable spatial differences:high in the Northern regions and low in the South.High blue water footprints were predominantly in the upper and middle reaches.The total virtual water flow associated with crop production was 19.15 billion m3,with green water flow exceeding blue water flow.The Northern regions served as virtual water exporters,while the Southern regions were net importers.[Conclusion]Effective management of green water resources is essential for sustainable water use in the Yellow River Basin.Special attention is required for the middle reaches due to their higher water consumption.Key strategies include prioritizing irrigation water allocation in the regions with low blue water footprints,optimizing crop planting structures,adopting water-saving technologies,and establishing compensation mechanisms for virtual water flow.These measures will promote the sustainable utilization of water resources throughout the basin.

Abstract:[Objective]Nitrogen and phosphorus leaching from vegetable farms poses significant environmental risks and reduces agricultural profitability.Here,we present the results of an experimental study on the effectiveness of combining drip irrigation and biochar amendment in reducing nitrogen and phosphorus leaching in cabbage fields.[Method]The field experiment was conducted with four treatments:① conventional chemical fertilization(CK),② soil amendment with 7 500 kg/hm2 of biochar combined with the conventional fertilization(B1),③ drip irrigation with a 50%reduction of the fertilizer applied in CK(B2),and ④ combining B2 with 7 500 kg/hm2 of biochar amendment(B3).For each treatment,we measured the cabbage yield,nitrogen and phosphorus leaching losses,and changes in soil physicochemical properties.[Result]① Drip irrigation combined with biochar amendment and fertilizer reduction did not significantly reduce cabbage yield compared to CK.② Compared to CK,B1 increased total nitrogen and phosphorus content in the soil by 12.29%and 10.21%,respectively,while reducing the concentrations of total nitrogen,nitrate nitrogen,and soluble phosphorus in leachate by 45.09%,69.99%,and 39.45%,respectively.③ B2 reduced the concentrations of total nitrogen,ammonium nitrogen,nitrate nitrogen,total phosphorus,and soluble phosphorus in leachate by 45.16%,34.87%,63.46%,57.90%,and 55.04%,respectively,compared to CK.④ B3,combining biochar amendment and fertilizer reduction under drip irrigation,reduced total nitrogen and phosphorus leaching by 46.66%and 48.57%,respectively,compared to CK.Principal component analysis indicated that fertilizer reduction was more effective in reducing nitrogen and phosphorus loss than biochar application,and their combination exhibited a synergistic effect.[Conclusion]The combination of biochar amendment with reduced fertilization under drip irrigation is highly effective in minimizing nitrogen and phosphorus leaching in vegetable fields,improving both environmental sustainability and agricultural profitability.

Abstract:[Objective]Drought is one of the most common abiotic stresses affecting crop production worldwide.Accurate forecasting is essential for improving irrigation management and water use efficiency.This study evaluates a multi-dimensional time series model for drought prediction based on the ICEEMDAN decomposition,aiming to provide a new method for improving drought prediction accuracy.[Method]The Santun River Irrigation District in Xinjiang was chosen as a case study.Monthly precipitation data from the Nianpanzhuang Station(1980-2023)were used,and the standardized precipitation index(SPI)was calculated for time intervals of 1,3,6,9,12,and 24 months.Six prediction models were compared:the autoregressive integrated moving average(ARIMA)model,gated recurrent unit(GRU)network,long short-term memory(LSTM)network,and their combinations with the improved complete ensemble empirical mode decomposition with adaptive noise(ICEEMDAN),resulting in ICEEMDAN-ARIMA,ICEEMDAN-GRU,and ICEEMDAN-LSTM models.These models were used to predict the SPI series at multiple time scales.Model accuracy was evaluated using root mean square error(RMSE),mean absolute error(MAE),and the coefficient of determination(R2).[Result]The accuracy of all six models improved as the time interval increased,reaching the highest at the 24-month interval.ICEEMDAN effectively stabilized the time series data and improved model accuracy for drought prediction.The accuracy of the models was ranked as follows:ICEEMDAN-ARIMA＞ICEEMDAN-GRU＞ICEEMDAN-LSTM＞ARIMA＞GRU＞LSTM.[Conclusion]Incorporating ICEEMDAN enhances the accuracy of drought prediction.Among the six models compared,ICEEMDAN-ARIMA was the most accurate and can be used for drought prediction in the studied region.

Abstract:[Objective]An optimal root architecture not only provides anchorage for plants but also enhances the acquisition of water and nutrients,which are unevenly distributed in the soil profile.This study experimentally investigates how root cutting can improve the root architecture of rice seedlings and its subsequent impact on water use efficiency.[Method]The experiment used the rice variety Lvhan 639 as the model plant and included two treatments.In the first treatment,half of the root system was removed at 5,7,9,and 11 days after seedling emergence.In the second treatment,root cutting was conducted 9 days after seedling emergence,with the root being cut at 1.5 cm from the root tip(A1.5),at the middle of the root(A1/2),and cut the root to 2.0 cm(A2.0).The control group did not undergo any root cutting.In each treatment,we measured root architecture,plant height,stem diameter,root-to-shoot ratio,photosynthetic traits,and water use efficiency of the seedlings.[Result]In the first treatment,the most favorable root architecture was observed when half of the root was cut 7 days after seedling emergence.In the second treatment,(A2.0)produced the optimal root architecture.Root cutting reduced the root-to-shoot ratio in all cases,although the differences between the two treatments were not statistically significant.In the first treatment,the lowest root-to-shoot ratio(0.228 5)occurred when the root was cut 9 days after seedling emergence.Root cutting improved water use efficiency,primarily by decreasing stomatal conductance.In the first treatment,cutting the roots 9 days after seedling emergence increased water use efficiency by 14.93%compared to the control.In the second treatment,cutting the roots to 2.0 cm showed the highest water use efficiency,with a 38.99%improvement over the control.[Conclusion]Root cutting can effectively enhance both root architecture and water use efficiency in rice seedlings.Among the methods tested,cutting half of the root 7 days after seedling emergence or trimming the root to 2.0 cm on the 9th day after seedling emergence were most effective for optimizing root development and increasing water use efficiency.

Abstract:[Objective]Nutrient and water interactions play a crucial role in their uptake by crops.Understanding their optimal combination is essential for improving the efficiency of their use.This paper presents a method for optimizing irrigation strategies for winter wheat production under varying nitrogen application rates in different hydrological years using the AquaCrop model.By integrating water footprint theory,we evaluate the water-fertilizer coupling under various scenarios.[Method]The study was conducted at the Weishan Irrigation District,where field experimental data were used to calibrate the AquaCrop model.The calibrated model was then used to simulate changes in winter wheat yield,aboveground biomass,and other crop traits.A total of 76 irrigation schemes under three nitrogen application rates were considered to determine optimal irrigation strategies for a typical hydrological year.Water footprint analysis was conducted using a soil moisture dynamic balance model to evaluate the sources of water uptake by the crop.[Result]The optimal irrigation schemes were determined based on dual objectives:high yield and irrigation water use efficiency.At a nitrogen application of 218 kg/hm2,the optimal irrigation strategy was as follows:In the wet year(2008-2009),irrigating during the jointing and filling stages,with a total irrigation amount of 108 mm.In the normal year(2019-2020),irrigating during the heading and filling stages,with a total irrigation amount of 162 mm.In the dry year(2012-2013),irrigating during the heading and filling stages,with a total irrigation amount of 136 mm.The optimal irrigation strategy for nitrogen applications of 198 and 178 kg/hm2 was similar to that for 218 kg/hm2.[Conclusion]Under water-limited conditions,prioritizing irrigation during the heading and filling stages of winter wheat maximizes benefits.Across all scenarios,the green water footprint predominated,while the blue water footprint played a supplementary role during the jointing,heading,and filling stages.The contribution of blue water was lowest in wet years and higher in both normal and dry years.

Abstract:[Objective]Improving irrigation water use efficiency(IWUE)is essential for sustainable agricultural development,especially in water-scarce regions.This paper examines how the application of water-saving technologies influences the IWUE of wheat production at the farm household level.[Method]Based on survey data collected from 512 farm households across key agricultural areas in Henan,Shandong,and Hebei provinces,we evaluated the impact of various water-saving technologies,including drip irrigation,sprinkler systems,canal lining,and field leveling,on IWUE.An econometric model was used to characterize household attributes such as land size,crop types,and access to services.Propensity score matching and an instrumental variable approach were employed to address potential selection bias and endogeneity.[Result]The average IWUE among the sampled farmers was 78.23%,which is significantly lower than the overall technical efficiency in wheat production.This suggests that,under current conditions,farmers could save an average of 21.71%of irrigation water by enhancing their IWUE.Compared to overall wheat production efficiency,IWUE exhibited greater variation among farmers.The adoption of water-saving technologies had a significant positive effect on IWUE,with its contribution ranking third after regional differences(as captured by the provincial dummy variable)and water pricing.Our results also revealed a'Matthew effect':farmers with already high IWUE benefited more from technology adoption,achieving notable improvements,whereas those with low baseline IWUE experienced relatively smaller gains.Furthermore,higher agricultural water prices were associated with more efficient water use,indicating that economic incentives play a crucial role.Regional differences in infrastructure,training,and support also moderated the impact of technology adoption.[Conclusion]Improving IWUE requires a multi-pronged approach.Local and provincial governments should invest in water-saving infrastructure and provide targeted training and support for households with low IWUE.Additionally,rationalizing agricultural water pricing and establishing a well-designed water rights system alongside market-based mechanisms can incentivize water conservation.These strategies,collectively,are key to enhancing the adoption of water-saving technologies and improving irrigation water use efficiency in wheat production.

Abstract:[Objective]Vegetation restoration is a widely applied strategy for improving soil quality in mining areas degraded by excavation and other anthropogenic activities.This study evaluates the effectiveness of different vegetation types in enhancing soil quality on a coal mine dump site.[Method]Field sampling and laboratory analyses were conducted to examine the physical and chemical properties of soils under three vegetation types:artificial forest land,artificial grassland,and bare land(no artificial plantation).Principal component analysis(PCA)was used to identify the key factors that influence soil quality.[Result]① The ability of vegetation types to retain soil water content in the 0-50 cm soil layer ranked as follows:artificial forest land(14.23％)＞artificial grassland(13.56％)＞bare land(11.07％).Conversely,soil bulk density followed the opposite trend.With increasing depth,soil water content decreased,while soil bulk density increased across all treatments.② Organic matter content in the 0-50 cm layer was highest under artificial forest land(28.29 g/kg),followed by artificial grassland(24.99 g/kg)and bare land(23.52 g/kg).Total nitrogen and phosphorus contents were also higher in the artificial forest land compared to the other treatments.Across all treatments,total and available potassium levels were relatively high,whereas alkali-hydrolyzed nitrogen and available phosphorus levels were low.③ Soil nutrient contents generally decreased with depth.Soil bulk density was negatively correlated with soil water content,organic matter,total nitrogen,total potassium,available nitrogen,available phosphorus,and available potassium.In contrast,organic matter showed strong positive correlations with all measured nutrients and water content.④ PCA results showed that the comprehensive soil quality indices for artificial forest land,artificial grassland,and bare land were 1.819,-0.433,and-1.386,respectively,indicating that artificial forest land had the greatest impact on soil quality restoration.[Conclusion]Vegetation restoration significantly improved the physical and chemical properties of soils in the coal mine dump sites,with artificial forest land being the most effective in enhancing overall soil quality.

Abstract:With increasing global water scarcity and widespread soil degradation threatening agricultural productivity and sustainability,there is an urgent need to develop efficient soil and water management practices.Water-saving irrigation techniques have gained increased attention for reducing water consumption while maintaining crop yields.Simultaneously,amending soil with exogenous organic matter has been accepted as a critical strategy for improving soil health and enhancing organic matter content and soil structure.This review explores the synergistic effects of water-saving irrigation and organic amendments on soil improvement,aiming to clarify the mechanisms underlying their positive impacts and highlight their potential applications in sustainable agriculture.We systematically review the efficacy of three main organic materials,straw,biochar and artificial humic substances,in improving soil quality under water-saving irrigation.Amending soil with these organic materials significantly increases soil organic matter,improves soil physicochemical properties,enhances water use efficiency,and mitigates greenhouse gas emissions from soils.We found that straw incorporation alone elevates methane(CH4)emissions under anaerobic conditions.However,when integrated with water-saving irrigation,it improves soil redox conditions,reduces net CH4 emissions,and enhances nitrogen mineralization.Soil amendment with biochar initially immobilizes nitrogen,but its combination with water-saving irrigation can optimize soil moisture content and slowly release nutrient to meet crop demand.This improves nitrogen use efficiency,especially in rice.Artificial humic substances have a minor effect on soil quality under flooded irrigation,but markedly enhance photosynthetic efficiency,carbon assimilation,and soil carbon stability under moderate water stress created by water-saving irrigation.Future research should focus on optimizing the combination of organic matter application and water-saving irrigation,developing precision agronomic practices,and evaluating the efficacy of these practices in areas with diverse climate and soil types in the context of global environmental challenges.