Effects of drip and flood irrigation on carbon dioxide exchange and crop growth in the maize ecosystem in the Hetao Irrigation District,China

Drip irrigation and flood irrigation are major irrigation methods for maize crops in the Hetao Irrigation District,Inner Mongolia Autonomous Region,China.This research delves into the effects of these irrigation methods on carbon dioxide(CO_(2))exchange and crop growth in this region.The experimental site was divided into drip and flood irrigation zones.The irrigation schedules of this study aligned with the local commonly used irrigation schedule.We employed a developed chamber system to measure the diurnal CO_(2)exchange of maize plants during various growth stages under both drip and flood irrigation methods.From May to September in 2020 and 2021,two sets of repeated experiments were conducted.In each experiment,a total of nine measurements of CO_(2)exchange were performed to obtain carbon exchange data at different growth stages of maize crop.During each CO_(2)exchange measurement event,CO_(2)flux data were collected every two hours over a day-long period to capture the diurnal variations in CO_(2)exchange.During each CO_(2)exchange measurement event,the biological parameters(aboveground biomass and crop growth rate)of maize and environmental parameters(including air humidity,air temperature,precipitation,soil water content,and photosynthetically active radiation)were measured.The results indicated a V-shaped trend in net ecosystem CO_(2)exchange in daytime,reducing slowly at night,while the net assimilation rate(net primary productivity)exhibited a contrasting trend.Notably,compared with flood irrigation,drip irrigation demonstrated significantly higher average daily soil CO_(2)emission and greater average daily CO_(2)absorption by maize plants.Consequently,within the maize ecosystem,drip irrigation appeared more conducive to absorbing atmospheric CO_(2).Furthermore,drip irrigation demonstrated a faster crop growth rate and increased aboveground biomass compared with flood irrigation.A strong linear relationship existed between leaf area index and light utilization efficiency,irrespective of the irrigation method.Notably,drip irrigation displayed superior light use efficiency compared with flood irrigation.The final yield results corroborated these findings,indicating that drip irrigation yielded higher harvest index and overall yield than flood irrigation.The results of this study provide a basis for the selection of optimal irrigation methods commonly used in the Hetao Irrigation District.This research also serves as a reference for future irrigation studies that consider measurements of both carbon emissions and yield simultaneously.

Impacts of Sulfur and Microalgae Co-fertilization on Saline-alkaline Soil of Sunflower Field in Hetao Irrigation District

[Objectives]To evaluate the impacts of the elemental sulfur(S 0)and micro-algae(MA)co-fertilization on saline-alkaline soil of sunflower field in the Hetao Irrigation District(HID).[Methods]The greenhouse pot experiment was conducted with four treatments:control(CK),single S 0 fertilization(S),single MA fertilization(A),and S 0 and MA co-fertilization(SA)for comparing the selected soil properties and sunflower plant heights and weights in different treatments.[Results]The results showed that the mean soil organic matter(SOM)under the SA(25.08 g/kg)was significantly higher than that for the CK(20.59 g/kg),S(22.47 g/kg),and A(22.95 g/kg).The mean pH under the SA(7.75)was significantly lower than that for the CK(8.14),S(7.82),and A(7.96).The mean soil exchangeable Na+concentration under the SA was significantly lower than that for the S.The mean soil electrical conductivity(EC)under the SA was 9.76%lower than that for the S.The means of Cl-(1.22 g/kg)and SO 2-4(1.90 g/kg)in soil under the SA were lower than that for the S(1.30,2.06 g/kg)and A(1.31,1.97 g/kg),respectively.For plant height 3 at the late stage of plant growth,the mean plant height 3 under the SA(89.00 cm)was higher than that of the CK(69.60 cm)and A(74.33 cm).The total weights of the fresh sunflower heads,fresh stems,and dry seeds under the SA were higher than that for the CK,S,and A.[Conclusions]In conclusion,the S 0 and MA co-fertilization had positive effects on improving saline-alkaline soils,the soil under the S 0 and MA co-fertilization could be better conditions for promoting sunflower growth than that for the S,Z,and CK,and thereby the S 0 and MA co-fertilization could be a new idea to improve saline-alkaline soil in the cold and arid regions.

The Impact of Water Pricing Policy on Local Environment-An Analysis of Three Irrigation Districts in China

As a high priority in dealing with the problem of water scarcity, the effect of water pricing policy remains a controversial issue, especially the environmental effect. Using household-level panel data of three irrigation districts （IDs） in the northern China, this paper probes the potential impact of water price rising on local environment. The examination shows that farmers will reduce the rice area as a response to the rising surface water prices. The changing cropping pattern will exert three-fold environmental impacts, including the dropping groundwater level resulting from the reduction of seepage and percolation of irrigated water and overexploitation of groundwater, the negative effect of non-point pollution from fertilizer and pesticide application, and the loss of field irrigation facilities. Water pricing is not a valid means of significantly reducing agricultural water consumption due to the substitution of groundwater for surface water, it will lead to negative environmental effect. It is an imperative task for Chinese government to improve the management efficiency at IDs.

Applying a salinity response function and zoning saline land for three fi eld crops: a case study in the Hetao Irrigation District, Inner Mongolia, China

Salinity is one of the major abiotic factors affecting the growth and productivity of crops in Hetao Irrigation District, China. In this study, the salinity tolerances of three local crops, wheat （Triticum aestinum L.）, maize （Zea mays L.） and sunflower （Helianthus annuus L.）, growing in 76 farm fields are evaluated with modified discount function. Salinity ecological zones appropriate for these local crops are characterized and a case study is presented for crop salinity ecological zoning. The results show that the yield reductions of wheat, maize and sunflower when grown in saline soils are attributed primarily to a reduction in spikelet number, 1 000-grain weight and seed number per head, respectively. Sunflower is the most tolerant crop among the three which had a salinity tolerance index （ST-index） of 12.24, followed by spring maize and spring wheat with ST-Indices of 9.00 and 7.43, respectively. According to the crop salinity tolerance results, the arable land in the Heping Village of this district was subdivided into four salinity ecological zones： the most suitable, suitable, sub-suitable and unsuitable zones. The area proportion of the most suitable zone for wheat, maize and sunflower within the Heping Village was 27.5, 46.5 and 77.5%, respectively. Most of the most suitable zone occurred in the western part of the village. The results of this study provide the scientific basis for optimizing the local major crop distribution and improving cultural practices management in Hetao Irrigation District.

Cause Analysis and Prediction of the Groundwater Level in Jinghuiqu Irrigation District

Groundwater environment evolution can comprehensively reflect groundwater dynamics. Based on the relationship between the groundwater system and the external environment in Jinghuiqu irrigation district, adopting the Principal Component Analysis method, variation characteristics of environmental factors including climate and human activity and their impact on groundwater were systematically analyzed. The results show that groundwater level in Jinghuiqu irrigation district has been significantly dropped in nearly 34 years;the reduction of surface water irrigation use, which reduced the amounts of groundwater recharge and destroyed the water balance, is considered as the most direct cause for falling of regional groundwater level. Besides, reduction in precipitation, increase of evaporation also accelerated the declining of the groundwater level at some extent. Finally, a predicting method of groundwater depth based on BP neural network is developed. The experimental results show that the predicting model can reasonablely predict the groundwater level in Jinghuiqu irrigation district with a high precision.

Characteristics and Development of Agricultural Soil in Hetao Irrigation District,Inner Mongolia

Hetao Irrigation District is located in the cold and arid region of Hetao Plain,Inner Mongolia,where the agricultural soil has unique characteristics.Although the agricultural soil properties in Hetao Irrigation Districts have been reported,the overall characteristics remain unclear.Through literature review and investigation,the overall characteristics,development patterns,and related reasons were explored,consequently providing theoretical support for enhancing soil utilization and formulating sustainable soil development strategies.The results showed that the agricultural soil in Hetao Irrigation District originated from the sedimentary layer and anthropogenic mellowing produced by the diversions of the Yellow River.The soil has periodic secondary salinization characteristics,accompanied by a slightly increasing pH value over time.It has low soil organic contents with a stable changing trend,low nitrogen,and phosphorus contents but high potassium and sulfur content,uneven nutrient distribution,diverse production performance,weak but stable ecological performance,and heterogeneous soil quality with a stable change trend.These findings indicate that this kind of soil can be used to plant diverse crops tolerant to different saline-alkali and requiring various nutrients.This agricultural soil is sustainable,but it is also faced with the problems of increased saline-alkali,nutrient loss,and pollution.

The Analysis of Dominance Degree of Land Use in Irrigation District——A Case Study of Jinghuiqu Irrigation District in Shaanxi Province

According to the remote sensing interpretation data in study area, statistics and the data concerning agricultural land classification of Shaanxi Province, on the basis of degree of dominance of land use, taking Jinghuiqu Irrigation District as an example, this paper adopts benefit-cost analysis method and the method of degree of dominance of land resources per capita to conduct analysis on degree of dominance of land. The results show that in study area, the ratio of cost and benefit of farmland is 1.5, with relative big value, indicating that farmland is the dominant land resource in Jinghuiqu Irrigation District; the abundance of land resources in study area is 0.73, the combination index of land resources is 2.3, and degree of dominance of land resources per capita is 0.32, indicating that the combination index of land resources in study area is relatively big, while degree of dominance of land resources per capita is relatively small, which shows that in study area, the combination of all kinds of land resources is in a poor state, with poor supporting ability. In view of the status quo that the combination of all kinds of land resources is in a poor state, with poor supporting ability in Jinghuiqu Irrigation District, the corresponding policy suggestions are put forward as follows: first, strictly implement the central policy and protect farmland resources; second, adjust land use structure and strive to promote benefit; third, make rational planning of land resources and take the road of sustainable development; fourth, take the irrigation district as the unit and establish use class and price standard of land in irrigation district.

An Empirical Framework of Washing Salinity by Irrigation to Maintain Soil Quality in Hetao Irrigation District

[Objectives] To summarize the characteristics of washing salinity by irrigation in Hetao Irrigation District, and propose the empirical framework of washing salinity by irrigation to maintain soil quality, and provide a theoretical basis for maintaining the sustainable development of soil in Hetao Irrigation District. [Methods] The methods of experiment, questionnaire, on-the-spot investigation and literature review were used. [Results] This study proposed the empirical framework of washing salinity by irrigation to maintain soil quality in Hetao Irrigation District. Seven factors of the framework, including flood irrigation, land leveling, plastic film mulching, fertilization, soil organic matter, pH and salinity, and their relationships were determined. The characteristics of these factors in Hetao Irrigation District were investigated(flooding irrigation with a large amount of irrigation water, high amount of fertilizer application, low organic matter, high pH, large variation of salinity, etc.). The mechanisms and effects of various factors affecting soil quality in Hetao Irrigation District were analyzed(the mean soil organic matter(SOM) and pH were kept in the range of 10.9-13.9 g/kg and 8.0-8.15 in recent 35 years, respectively, and increased slightly, etc.). [Conclusions] The empirical framework can be used as a theoretical norm for evaluating soil quality under the condition of washing salinity by irrigation. Under the condition of washing salinity by irrigation, the agricultural soil quality in Hetao Irrigation District showed a stable trend over time. Using this framework, we can find soil problems, and adjust some unbalanced factors to maintain the stability of soil quality in Hetao Irrigation District, and can also provide a reference for other areas.

Balance of Irrigation Water in Jinghui Canal Irrigation District of China

Jinghuiqu Canal Irrigation District is an old irrigation area with a long history.Due to natural and man-made factors,the inflow and rainfall of the irrigation area are decreasing,which seriously affects agricultural production water in the irrigation area and constantly threatens the safety of irrigation water in irrigation area.In this paper,natural and man-made factors of affecting irrigation water in irrigation area are analyzed,and it is proposed that main channels of solving safety of irrigation water are enhancing the utilization of canal water and optimizing the allocation of canals and wells.

Reducing water and nitrogen inputs combined with plastic mulched ridge-furrow irrigation improves soil water and salt status in arid saline areas,China

Plastic mulched ridge-furrow irrigation is a useful method to improve crop productivity and decrease salt accumulation in arid saline areas.However,inappropriate irrigation and fertilizer practices may result in ecological and environmental problems.In order to improve the resource use efficiency in these areas,we investigated the effects of different irrigation amounts(400(I1),300(I2)and 200(I3)mm)and nitrogen application rates(300(F1)and 150(F2)kg N/hm^(2))on water consumption,salt variation and resource use efficiency of spring maize(Zea mays L.)in the Hetao Irrigation District(HID)of Northwest China in 2017 and 2018.Result showed that soil water contents were 0.2%-8.9%and 13.9%-18.1%lower for I2 and I3 than for I1,respectively,but that was slightly higher for F2 than for F1.Soil salt contents were 7.8%-23.5%and 48.5%-48.9%lower for I2 than for I1 and I3,but that was 1.6%-5.5%higher for F1 than for F2.Less salt leaching at the early growth stage(from sowing to six-leaf stage)and higher salt accumulation at the peak growth stage(from six-leaf to tasseling stage and from grain-filling to maturity stage)resulted in a higher soil salt content for I3 than for I1 and I2.Grain yields for I1 and I2 were significantly higher than that for I3 and irrigation water use efficiency for I2 was 14.7%-34.0%higher than that for I1.Compared with F1,F2 increased the partial factor productivity(PFP)of nitrogen fertilizer by more than 80%.PFP was not significantly different between I1F2 and I2F2,but significantly higher than those of other treatments.Considering the goal of saving water and nitrogen resources,and ensuring food security,we recommended the combination of I2F2 to ensure the sustainable development of agriculture in the HID and other similar arid saline areas.

现代化数字灌区建设主体功能及主要应用结构体系探讨

基于对物理灌区的现代化和模拟灌区的数字化认知,分析总结了现代化数字灌区建设应着力完成的“灌区识别”“立体感知”“精准控制”“信息交互”“管理调度”等“五大主体功能”结构体系;基于智慧水利建设和灌区高效运管需求,高效地模拟渠系水流,系统梳理了以“节点流量过程”为输入和输出的灌区概化图,研究提出了现代化数字灌区建设主要业务应用结构体系,即构建以“数据库”为载体,“数学模型”为支撑,基于“灌区一张图”基础之上的“组织管理、工程管理、安全管理、泵站管理、农业节水与供用水管理、经济管理、信息化管理、公共服务”等“九大业务应用”为交互的的整体架构,以期有效提升灌溉供水服务的安全性、公平性、可靠性和灵活性。

智慧水利理论体系与数字孪生流域虚拟模型研究成果述要

智慧水利是水利高质量发展的显著标志之一。围绕智慧水利理论体系不完善、流域映射精准度不高、模型精度不高、决策支撑程度低等问题,建立了由智慧流域基础理论、数字孪生流域基础理论和智能水网理论框架组成的智慧水利理论体系,研究了由数字孪生感知节点模型、数字孪生降水遥感模型、数字孪生蒸散发遥感模型、数字孪生土壤水遥感模型、数字孪生水体遥感模型、数字孪生地下水遥感模型、数字孪生水质遥感模型组成的数字孪生流域感知模型,构建了由数字孪生流域水文模型、数字孪生水动力水质模型、数字孪生动态调控模型、数字孪生虚拟仿真模型、数字孪生协同决策模型、数字孪生并行组合模型等组成的数字孪生流域虚拟模型。研究成果可为我国智慧水利建设提供理论基础和技术支撑。

数字孪生灌区建设核心要义与关键技术探讨

梳理了数字孪生技术缘起背景和发展进程,分析指出数字灌区是建设数字孪生灌区的重要基础,现代化数字灌区是推进数字孪生灌区建设的重要发展阶段。基于对数学模型的功能认知,在数字孪生灌区框架下,首次提出将数学模型划分为3个层次,即普适性平台模型、针对性应用模型和友好性交互模型。同时,基于数字孪生灌区定义,分析指出数字孪生模型具有实时动态性及闭环反馈性本质特征,物理灌区与孪生灌区存在同步仿真、虚实交互与迭代优化的过程,二者在灌区全生命周期相互影响,相互促进,孪生灌区不仅随着物理灌区的改变而实时改变,而且基于孪生灌区所做的分析和决策也会实时反馈给物理灌区,并影响物理灌区的行为。因此,具体工作实践中,应基于物理灌区现代化改造需要,发现问题,遵循确有需要、节水高效和可以持续的原则,精准选择灌区数字孪生对象,优化创新数学模型,着力突破关键技术,有序开发重点应用,强化网络安全和数据安全,以期能够更有序、更精准、更高效地推进数字孪生灌区建设。

Spectral matching based remote sensing identification of two main crop rotation patterns in a large irrigation district

The rapid identification of planting patterns for major crops in a large irrigated district has vital importance for irrigation management,water fee collection,and crop yield estimation.In this study,the OTSU algorithm and Mean-Shift algorithm were employed to automatically determine threshold values for mapping two main rotated crop patterns at the pixel scale.A time series analysis was conducted to extract the spatial distribution of rice-wheat and wheat-maize rotations in the Chuanhang irrigation district from 2016 to 2020.The results demonstrate that both threshold segmentation algorithms are reliable in extracting the spatial distribution of the crops,with an overall accuracy exceeding 80%.Additionally,both Kappa coefficients surpass 0.7,indicating better performance by OTSU method.Over the period from 2016 to 2020,the area occupied by rice-wheat rotation cropping ranged from 12500 to 14400 hm 2;whereas wheat-maize rotation cropping exhibited smaller and more variable areas ranging from 19730 to 34070 hm 2.These findings highlight how remote sensing-based approaches can provide reliable support for rapidly and accurately identifying the spatial distribution of main crop rotation patterns within a large irrigation district.

淠史杭灌区干旱推演及抗旱预案调控研究

水资源干旱是限制灌区可持续发展的关键因素。为提高灌区的干旱防治能力,使其更好的发挥其在节水、减灾方面的作用,以淠史杭灌区为研究区,通过划分水资源配置子单元和设置调蓄节点,采用公平性最优和供水缺水率最小作为目标函数,总量控制、供水能力、分质供水等作为约束条件,采用基于精英策略的非支配遗传改进算法求解,构建区域General Water Allocation and Simulation Model(GWAS)模型;以2022年为现状基准年,与2023规划年组合,分为连续干旱与不连续干旱两大类,基于灌区水资源“应急干旱三次平衡”调控思想,分析灌区水资源在不同干旱情景下缺水的基础上,展开水资源抗旱配置研究,推演分析不同抗旱方案下水资源供需平衡情况。结果表明:连续干旱年中,灌区2023规划年在情景Ⅰ(P=90%)、情景Ⅱ(P=80%)来水频率下,各乡镇配置单元均存在不同程度的缺水情况,区域总缺水率分别为35.1%、20.8%;不连续干旱年中,2023规划年在情景Ⅲ(P=50%)来水频率下,模型基准配置水量基本可以满足区域各乡镇水量需求,区域总缺水率为5.9%。经不同抗旱方案尾部泵站补水、调整作物种植结构及外调水的优化配置后,三种情景下区域总缺水率最终都降为0%,优化后各配置单元供水改善效果显著。研究成果可为淠史杭灌区未来在应对不同干旱类型情景下水资源的合理调整提供技术支撑,并且可为实现该区域水资源统一管理和水量的统一调配提供理论依据。

基于C-D生产函数的灌区节水贡献率研究

为挖掘灌区节水目标实现路径,提高灌区用水效率,研究分析了大中型灌区水利工程建设管护对节水战略目标的贡献程度。以江苏省为例,选取6个典型灌区,收集了2015-2022年统计数据,分别计算渠系工程、田间工程和非工程措施的节水潜力,并据此计算灌区总节水潜力。以水利工程投入、劳动力投入、土地投入、技术进步作为自变量,灌区总节水潜力作为因变量,利用改进C-D生产函数来构建“双对数模型”。利用SPSS软件对数据进行多元线性回归,运用步进法剔除无关变量后建立最优方程,通过弹性系数测算不同变量对节水目标的贡献率大小。结果表明,在灌区总节水潜力组成中,渠系工程节水占比最大,田间工程节水占比最小;水利工程投入、土地投入、技术进步对节水目标的平均贡献率分别为45.5%、30.4%、5.2%,但技术进步贡献率呈现逐年增长的趋势,水利工程收入贡献率先减小后增大。大型灌区水利工程对灌区节水的贡献率高于中型灌区。该研究将C-D生产函数模型运用到节水评价当中,结果较为合理可靠,可为大中型灌区节水发展提供技术参考。

漳河水库灌区水效领跑者引领行动的实践与评价

开展灌区水效领跑者引领行动及评价,是强化、规范农业灌溉用水管理的重要措施。基于有关部门印发的《灌区水效领跑者引领行动实际细则》和漳河水库灌区实践情况,采用层次分析方法(AHP),建立了漳河水库灌区水效领跑者引领行动的评价指标体系和评价阈值,分析了节水技术评价、节水管理评价和鼓励性评价等敏感指标,并对其进行评价,结果表明漳河水库灌区水效领跑者引领行动综合评价值0.94与实际情况吻合。

交口灌区农业水土资源承载力评价及障碍因子诊断

【目的】评价交口灌区农业水土资源承载力及其障碍因子。【方法】以交口灌区为研究对象,构建包括水土资源、社会、经济、生态环境4个准则层的水土资源承载力评价指标体系,采用组合赋权的TOPSIS模型对交口灌区水土资源承载力进行综合评价,采用障碍度模型诊断制约灌区农业水土资源承载力的主要障碍因子。【结果】2016—2020年,交口灌区水土资源承载力呈稳步提升态势,各区、县的水土资源承载力差距逐渐缩小;灌区不同区、县的水土资源承载力水平差异显著,灌区北部承载力水平高于灌区南部,各区、县承载力指数介于0.257~0.621;水土资源和生态环境系统中的单位耕地农药施用量、水土资源匹配系数、单位耕地施肥量、垦殖率、生态环境用水率、水资源开发利用率是制约交口灌区水土资源承载力提升的主要障碍因子。【结论】水土资源和生态环境是影响灌区水土资源承载力的关键要素,灌区应以可持续发展理论为导向,注重农业发展与生态保护并重,综合提升灌区承载力。

基于MWatNet模型的河套灌区解放闸灌域灌溉水体提取

为提高灌溉农田中灌溉水体的识别精度,以河套灌区解放闸灌域作为研究区,基于Sentinel-2遥感影像,结合灌区实际情况对地表水体提取模型(WatNet)进行改进,得到MWatNet模型并提取灌溉水体。采用总体精度(Overall accuracy,OA)、平均交并比(Mean intersection over union,MIoU)、F1值等水体提取精度指标进行综合评价。结果表明:改进后的地表水体提取模型(MWatNet)在解放闸灌域农田灌溉水体的提取上具有较好的识别精度,模型总体精度达到96%,平均交并比达到83%,F1值为80%,实地调研验证准确度为85.7%;对比原WatNet、水体语义分割模型(Deeplabv3_plus)和水体提取模型(Deepwatermapv2),MWatNet在灌溉水体提取的连结性、剔除道路和城镇干扰等方面,均表现出更好的效果和模型运行效率。利用该模型可以实现灌溉水体定量化表征,为灌溉用水调度提供了数据支撑。

非接触式雷达波测流系统在桑干河七一灌区中的应用

为了提高水文测流的效率和时效,开发无人值守自动测流系统非常必要。基于自动化控制理论,设计了非接触雷达波测流系统。该系统使用非接触式雷达波流速仪作为水面流速的测量传感器,能自动完成测流过程,具备优良的差错控制和系统辅助管理功能,可有效应对七一灌区无人值守的流量自动测量难题。