Agricultural Water Management最新文献

{"title":"Optimized water and nitrogen management improves photosynthesis, yield, and resource use efficiency of maize under mulched drip irrigation","authors":"Yi Fan ,&nbsp;Yuyi Zhang ,&nbsp;Zixiang Wang ,&nbsp;Ying Li ,&nbsp;Yang Wang ,&nbsp;Hejing Tang ,&nbsp;Zhandong Liu ,&nbsp;Xingpeng Wang","doi":"10.1016/j.agwat.2026.110219","DOIUrl":"10.1016/j.agwat.2026.110219","url":null,"abstract":"<div><div>Photosynthesis underpins crop yield formation, and understanding its response to integrated water-nitrogen management is essential for sustainable agricultural development. While drip fertigation has proven effective in conserving water, enhancing yield and reducing nutrient losses, its regulatory effects on photosynthetic performance of densely-planted maize under plastic-mulched drip irrigation in arid regions remain poorly understood. To address this knowledge gap, a two-year field experiment was conducted from 2024 and 2025 to investigate the combined effects of irrigation and nitrogen fertilization on maize photosynthesis and yield formation, with irrigation amounts ranging from 42.75 to 52.5 mm and nitrogen application rates from 0 to 360 kg ha⁻¹. The results showed that moderate nitrogen application significantly increased relative chlorophyll content, net photosynthetic rate, maximum quantum efficiency, effective quantum yield of PSII, and photochemical quenching, while markedly reducing non-photochemical quenching. These combined effects promoted carbon assimilation and assimilate accumulation, benefiting grain yield formation. However, excessive nitrogen application diminished these beneficial effects. Among all treatments, irrigation with 47.25 mm of water combined with 240 kg ha⁻¹ of nitrogen fertilization was identified as optimal for improving photosynthesis and grain yield, achieving a two-year average yield of 20,873.78 kg ha⁻¹.Compared with conventional fertigation practices used by local farmers, this optimal treatment reduced irrigation water and nitrogen fertilizer inputs by 10.0 % and 33.3 %, respectively, while increasing grain yield, irrigation water use efficiency, and nitrogen partial factor productivity by 18.77 %, 30.56 %, and 78.17 %, respectively. Structural equation modelling revealed that the optimal fertigation enhanced grain yield primarily through increasing photosynthetic capacity and PSII function. A comprehensive evaluation using the TOPSIS method further indicated that the optimal fertigation provided the greatest synergistic benefits in photosynthetic performance, and resource-use efficiency. Overall, this study results demonstrate that optimizing fertigation can synergistically improve photosystem function, resource-use efficiency and crop productivity, they provide practical guidance for sustainable and efficient maize production under drip irrigation in arid regions.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"326 ","pages":"Article 110219"},"PeriodicalIF":6.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the mitigation effects of irrigation methods on a record-breaking drought: Crop Yield and Economic Loss in Shaanxi Province, China","authors":"Hao Chen ,&nbsp;Xinhao Li ,&nbsp;Bate Zuo ,&nbsp;Ziji Lv ,&nbsp;Jiaqi Chen ,&nbsp;Jiaxi Wang ,&nbsp;Wenyan Ge ,&nbsp;Shangyu Shi ,&nbsp;Jianqiao Han ,&nbsp;Jinshi Jian ,&nbsp;Fei Wang","doi":"10.1016/j.agwat.2026.110247","DOIUrl":"10.1016/j.agwat.2026.110247","url":null,"abstract":"<div><div>Drought events are intensifying under climate change, creating mounting risks for crop production and rural livelihoods in dryland regions. Shaanxi Province experienced a record drought in the 2025 agricultural season, reported as the most severe in the past 75 years, causing major impacts on food production and farm income. We assessed drought impacts and the mitigation role of irrigation by integrating multi-decadal meteorological records (1950–2025), field soil-moisture profiles (0–200 cm; 80 sites), crop growth observations (plant height and vegetation index; n = 175), and a province-wide household survey (n = 1025; 511 field interviews and 514 online responses). Meteorological analysis shows significant long-term drying in Shaanxi, and 2025 exhibited sharp anomalies, with precipitation and shallow soil water content reduced by 31 % and 16 % relative to 2024, confirming a severe drought year. Field sampling indicates strong shallow desiccation: mean soil moisture at 0–20 cm was only 9.4 %, well below the Loess Plateau’s typical field capacity, while deeper layers (&gt;20 cm) remained around 12 %, offering limited buffering. Crop growth responses were severity-dependent, with plant height and vegetation index reduced by 35 % under moderate drought and by 76 % and 52 %, respectively, under severe drought compared with normal years. Survey results reveal heterogeneous vulnerabilities: wheat was relatively less affected (28 % yield loss, ∼6180 RMB/ha), whereas vegetables and orchards experienced much larger reductions (48–51 % yield loss; 18,675–23,520 RMB/ha). Irrigation significantly mitigated losses, with well and drip irrigation reducing yield declines to 28 % and 19 %, respectively, versus 46 % under rainfed conditions. Overall, the results identify shallow root-zone desiccation as a primary constraint and show that unequal access to efficient irrigation drives unequal drought outcomes, supporting targeted water-management and crop adaptation strategies to strengthen drought resilience in dryland farming systems.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"326 ","pages":"Article 110247"},"PeriodicalIF":6.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146778238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reducing nitrogen use under optimal irrigation and planting date can sustain sugarcane yield and gross margin under climate change","authors":"Shijin Yao ,&nbsp;Bin Wang ,&nbsp;De Li Liu ,&nbsp;Fangzheng Chen ,&nbsp;Siyi Li ,&nbsp;Keyu Xiang ,&nbsp;Jianqiang He ,&nbsp;Mingxia Huang ,&nbsp;Meichen Feng ,&nbsp;Qiang Yu","doi":"10.1016/j.agwat.2026.110160","DOIUrl":"10.1016/j.agwat.2026.110160","url":null,"abstract":"<div><div>Sugarcane is a vital economic crop in Australia, supporting both agricultural and regional economies. However, its heavy reliance on high nitrogen (N) inputs raises costs and results in considerable losses to the environment. While climate warming is projected to enhance sugarcane yield in subtropical New South Wales (NSW), it remains unclear whether this benefit, combined with adaptive management, can sustain yields under reduced N use in future climates. To address this, the APSIM-Sugarcane model, validated with high accuracy (R²=0.82 for yield and 0.73 for gross margin), was driven by projections from 27 global climate models under two Shared Socio-economic Pathways (SSP2–4.5 and SSP5–8.5) to simulate yield responses to varying N rates, irrigation levels, and planting dates across the main production regions of Condong, Broadwater, and Harwood in northern coastal NSW. Results indicated that under future climates, yield and gross margin increased under current management practices, with further gains under optimal management (50 % PAWC irrigation and planting in September). The optimal strategy remained unchanged across N rates, but yield and gross margin declined with reduced inputs. The lowest feasible N rate under future climates sustaining current yield (101–127 t ha⁻¹) and gross margin (2147–3122 AU$ ha⁻¹) was 60 kg ha⁻¹ (a 40 % reduction from the current N rate of 100 kg ha⁻¹). At this level, irrigation was the primary driver of yield and gross margin, followed by temperature and CO₂. This study highlights practical nitrogen reduction strategies sustaining sugarcane productivity, profitability, and environmental sustainability under future climates in Australia.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"326 ","pages":"Article 110160"},"PeriodicalIF":6.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling nitrogen fluxes in a tile-drained cropping system in the Midwest using an enhanced SWAT model","authors":"Muhammad Rizwan Shahid ,&nbsp;Junyu Qi ,&nbsp;Bryan D. Emmett ,&nbsp;Robert W. Malone ,&nbsp;Natalia Rogovska ,&nbsp;Peter L. O’Brien ,&nbsp;John L. Kovar ,&nbsp;Anna Radke ,&nbsp;Gary W. Feyereisen ,&nbsp;Kevin W. King ,&nbsp;Mark Williams ,&nbsp;Daniel Moriasi ,&nbsp;Michael J. Castellano","doi":"10.1016/j.agwat.2026.110225","DOIUrl":"10.1016/j.agwat.2026.110225","url":null,"abstract":"<div><div>Artificial (tile) drainage systems are extensively implemented across the U.S. Midwest to enhance crop production in poorly drained soils; however, they also pose environmental challenges by significantly altering nitrogen fluxes within agricultural landscapes. In response, sustainable intensification strategies seek to increase agricultural productivity while reducing environmental impacts, often through improved management practices such as cover cropping and conservation tillage. Effectively evaluating the trade-offs and synergies of agricultural management practices demands advanced modeling tools capable of representing coupled biogeochemical and hydrological processes across diverse spatial and temporal scales. This study presents the first application of an enhanced version of the Soil and Water Assessment Tool (SWAT), integrated with Century/DayCent-based biogeochemical modules, to simulate both nitrate (NO₃⁻) loss and nitrous oxide (N₂O) fluxes in a tile-drained corn-soybean system. The model was applied to long-term field data (2004–2010) from an Iowa site with two treatments: with and without winter rye cover crops. With careful calibration, the model reproduced tile discharge and crop yields well and captured the direction and magnitude of cover-crop reductions in NO₃⁻ losses. However, interannual variability in NO₃⁻ export and event-scale N₂O peaks remained difficult to reproduce, likely due to limited sampling frequency and structural constraints in soil hydrology, solute transport, and vertical resolution. The model simulated a ∼41 % reduction in NO₃⁻ leaching with cover crops, close to the observed ∼50 %. In contrast, effects on average daily N₂O flux varied by year and conditions, ranging from −30–67 % (observed: −24–28 %). These results support the model’s use for assessing long-term nitrogen-loss responses to cover crops in tile-drained systems, while highlighting priorities for improving event-scale biogeochemical simulations.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"326 ","pages":"Article 110225"},"PeriodicalIF":6.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of soil hydrothermal condition and potato growth under different colored plastic film mulch in an arid region","authors":"Youliang Zhang ,&nbsp;Qianyun Deng ,&nbsp;Zhiming Qi ,&nbsp;Fengxin Wang ,&nbsp;Matthew Sima ,&nbsp;Chunli Hua ,&nbsp;Qiu Luo ,&nbsp;Shaoyuan Feng","doi":"10.1016/j.agwat.2026.110238","DOIUrl":"10.1016/j.agwat.2026.110238","url":null,"abstract":"<div><div>Potato (<em>Solanum tuberosum</em> L.), the fourth important global food crop, is sensitive to stress of soil water and temperature, especially in arid regions. To mitigate the stress, plastic film mulch combined with drip irrigation has been widely adopted to improve thermal and moisture conditions and potato growth which depend on the film color. Critically, it is challenging to predict soil water and temperature and potato growth under different colored film mulches. Process-based simulation models offer a powerful tool to address this complexity. However, the capability of the modified RZ-SHAW model to accurately simulate the soil hydrothermal conditions and the drip irrigated potato growth under different colored plastic films has not been adequately evaluated. In this research, the simulation ability of the modified RZ-SHAW model on soil moisture, soil temperature, yield, water consumption, leaf area index, and dry matter under transparent mulch (TM), no mulch (NM), and black mulch (BM) treatments was evaluated using two years of field potato experimental data. The simulation results showed that the modified RZ-SHAW model effectively captured soil water and temperature variations during the entire potato growth stage. The average root means squared error (RMSE) for soil water content was 0.029, 0.038, and 0.037 cm³ cm⁻³, and for soil temperature was 3.0, 2.0, and 3.0 °C with TM, NM, and BM, respectively. The relative RMSEs (RRMSE) were 15.3%, 22.0%, and 19.9% for soil water content and 17.0%, 11.7%, and 17.6% for soil temperature with TM, NM, and BM, respectively. The modified RZ-SHAW model had an advantage in the simulation of crop evapotranspiration and tuber yield. Overall, this model can simulate soil water and heat condition and potato growth under colored film mulches, which can provide guidelines for high yield potato cultivation.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"326 ","pages":"Article 110238"},"PeriodicalIF":6.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146777220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prolonged drought strongly suppresses temperate grasslands actual evapotranspiration: Insights from eddy covariance observations upscaling","authors":"Lexin Ma ,&nbsp;Zhi Chen ,&nbsp;Quanhong Lin ,&nbsp;Tianxiang Hao ,&nbsp;Meng Yang ,&nbsp;Jianxing Zhu ,&nbsp;Linfei Yu ,&nbsp;Mingyu Sun ,&nbsp;Yong Lin ,&nbsp;Tao Li ,&nbsp;Fubo Yu ,&nbsp;Zongxu Yu ,&nbsp;Jiwen Li ,&nbsp;Guirui Yu","doi":"10.1016/j.agwat.2026.110211","DOIUrl":"10.1016/j.agwat.2026.110211","url":null,"abstract":"<div><div>Despite frequent droughts in East Asian grasslands, most studies have concentrated on their impacts on carbon balance, leaving limited understanding of actual evapotranspiration (ET_a) responses under prolonged drought conditions. The Chinese Grassland Transect (CGT), located in the transition zone between croplands and grasslands, spans alpine grasslands (AG) and temperate grasslands (TG) and provides a natural laboratory for examining drought impacts on water dynamics. In this study, monthly data from 18 eddy covariance sites were used to train and evaluate 24 machine learning models, and the best-performing model was applied to estimate ET_a across AG and TG. Results showed a persistent increase in ET_a in AG, whereas TG experienced significant declines during 1999–2011 due to prolonged drought associated with reduced precipitation (P). The variability of P in TG was largely controlled by the El Niño - Southern Oscillation (ENSO), whereas in AG, P was primarily influenced by the South Asian monsoon system and the region was less affected by drought impacts due to the Tibetan Plateau. Interannual variability in net ecosystem productivity (NEP) closely tracked the water balance, with NEP in TG more strongly influenced by water input (P), whereas NEP in AG was more strongly influenced by water loss (ET_a). These findings reveal contrasting ET_a responses to prolonged drought along the CGT and highlight the key roles of ENSO and monsoon systems in regional hydrology.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"326 ","pages":"Article 110211"},"PeriodicalIF":6.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two independent water balance approaches demonstrate extensive use of groundwater by rainfed crops","authors":"Adam P. Schreiner-McGraw,&nbsp;Claire Baffaut","doi":"10.1016/j.agwat.2026.110218","DOIUrl":"10.1016/j.agwat.2026.110218","url":null,"abstract":"<div><div>In the rainfed cropland of the U.S. Corn Belt effective management requires an understanding of where crop water originates. Thus, quantification of where in the subsurface crops extract water from is warranted. In this study, we co-located measurements of crop water use, soil moisture, and groundwater level at three locations within a field with potentially sustainable management practices (ALT field). The field has a restrictive claypan soil layer previously thought to restrict vertical water movement. We used these measurements to calculate a point-scale water balance and show that crops draw important amounts of water from below the restrictive claypan. These calculations contain considerable uncertainty but show that between 31 % and 53 % of growing season water use is sourced from below the claypan. There was considerable variability between the three locations. To test if our results were robust over larger spatial scales and a longer period, we calculated the groundwater flux with independent field-scale water budgets using measurements of precipitation, evapotranspiration (<em>ET</em>), soil moisture, and runoff. We did this at the ALT field as well as a field managed with the prevailing practices of the region (PRV). This field-scale water balance showed that both fields drew considerably from water beneath the claypan, supplying an average of 29 % and 25 % of total growing season <em>ET</em> for the ALT and PRV fields, respectively. Values of non-growing season groundwater flux were not sufficient to recharge this water use, highlighting the importance of complex groundwater recharge pathways in rainfed croplands of the U.S. Corn Belt.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"326 ","pages":"Article 110218"},"PeriodicalIF":6.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of irrigation uniformity on the delineation of homogeneous zones in a pear orchard","authors":"L. Bonzi ,&nbsp;M. Carrara ,&nbsp;F. Hamouda ,&nbsp;S. Marasco ,&nbsp;R. Massai ,&nbsp;À. Puig-Sirera ,&nbsp;D. Remorini ,&nbsp;G. Rallo","doi":"10.1016/j.agwat.2026.110224","DOIUrl":"10.1016/j.agwat.2026.110224","url":null,"abstract":"<div><div>Spatial variability analysis is fundamental in precision orchard management, yet non-uniform irrigation can distort the delineation of management zones (MZs), leading to sub-optimal operational decisions. This study investigates the impact of irrigation non-uniformity on MZ delineation in a 7-ha micro-irrigated pear orchard by integrating topographic information (Z), vegetation vigor (NDVI), soil apparent electrical conductivity (ECa), and emitter flow rates (Q). Geostatistical analyses show that elevation and ECa are the primary drivers of structured field variability, while Q reveals substantial hydraulic heterogeneity—most notably in the <em>Carmen</em> sector, which displays both the lowest average discharge and the greatest variability in emitter performance. Incorporating Q into fuzzy c-means clustering increases zoning complexity, leading to more MZs than classifications based solely on soil and vegetative indicators. When all variables (Z, NDVI, ECa, Q) are combined, the orchard is optimally divided into four management zones that more accurately reflect the interplay of hydraulic, topographic, and soil-related factors shaping crop response. These findings indicate that a lower distribution uniformity of the irrigation can introduce operational artefacts into spatial analyses, highlighting the value of optimising the irrigation layout and adopting zone-specific irrigation management to improve system performance and crop responsiveness.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"326 ","pages":"Article 110224"},"PeriodicalIF":6.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Out-scaling apparent conductivity from ground acquired electromagnetic induction using satellite reflectance data to assess regional salinity and waterlogging","authors":"Mark R. Glover ,&nbsp;Jorge L. Peña-Arancibia ,&nbsp;Debolina Sarkar ,&nbsp;Manoj Kumar Nanda ,&nbsp;Yingying Yu ,&nbsp;Mohammed Mainuddin ,&nbsp;Mustafa Kamal Shahadat ,&nbsp;Md. Maniruzzaman ,&nbsp;Khokan Kumer Sarker ,&nbsp;Md. Belal Hossain ,&nbsp;Argha Ghosh ,&nbsp;Priya Lal Chandra Paul ,&nbsp;Sukanta Kumar Sarangi ,&nbsp;Sukamal Sarkar ,&nbsp;Edward G. Barrett-Lennard ,&nbsp;Donald S. Gaydon","doi":"10.1016/j.agwat.2026.110135","DOIUrl":"10.1016/j.agwat.2026.110135","url":null,"abstract":"<div><div>The salt-affected coastal zone of the Ganges-Brahmaputra Delta (CZGBD, ∼37,400 km²), is home to approximately 54 million people, many of whom face livelihood challenges. Primarily an agricultural economy, soil salinity and waterlogging during the dry season (Rabi, from November to March), plus climate induced natural disasters and inadequate infrastructure, significantly decrease food security. The spatial delineation of a salinity/waterlogging proxy, Apparent Conductivity (ECa), can indicate locations of impaired agricultural productivity, and thereby improve the efficiency of limited supplies of irrigation water. To assist in this, a novel technique was developed to integrate and out-scale 19 ground-based electromagnetic induction ECa surveys conducted in agricultural sites with Sentinel-2 10 m reflectance data. These data are used to predict 5 ECa classes (from low to severe) regionally from 2019 to 2023 using a Random Forest model, with a cross-validation accuracy of 66 %. The observed regional ECa dynamics are qualitatively linked to antecedent monsoon rainfall, discharge and the hydromorphology of the CZGBD. Relatively higher monsoon rainfall, particularly late in the season, results in higher ECa classes that are related to waterlogging in areas to the north of the CZGBD. Higher ECa classes are also related to soil salinity in areas of decreased fluvial activity over time, particularly in the southwest of the CZGBD. These maps can be used to guide future investments in waterlogging mitigation (drainage systems), prioritize irrigation supply network upgrades, support improved farming systems choices including reducing the risks of Rabi season crop failure and inform supply chain investment or management decisions.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"326 ","pages":"Article 110135"},"PeriodicalIF":6.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of critical soil moisture thresholds and the water–energy regulation mechanisms in semi-arid sand dune–meadow ecosystems","authors":"Simin Zhang ,&nbsp;Limin Duan ,&nbsp;Yongzhi Bao ,&nbsp;Lina Hao ,&nbsp;Xin Tong ,&nbsp;V.P. Singh ,&nbsp;Tingxi Liu","doi":"10.1016/j.agwat.2026.110235","DOIUrl":"10.1016/j.agwat.2026.110235","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Dryland ecosystems are highly sensitive to global change, with their carbon–water cycling strongly regulated by soil moisture (SM). The critical soil moisture content at which the ecosystem shifts from energy limitation to water limitation during drought can be regarded as a soil moisture threshold that characterizes this regulation. Accurately quantifying critical soil moisture thresholds (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) remains a key scientific challenge in elucidating the mechanisms of carbon–water interactions. This study focuses on the Horqin Sandy Land, one of the four major sandy regions in northern China, using long-term eddy covariance and environmental data collected from dune and meadow ecosystems during the growing seasons (May–September) from 2013 to 2024. Three methods—evaporative fraction (EF), covariance (Cov), and correlation difference (corr)—were used to identify to &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, marking the transition from energy-limited to water-limited states during drought. Furthermore, interpretable machine learning (XGBoost–SHAP) and dominance analysis (DA) were employed to elucidate the driving mechanisms of &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;. Results showed that meadow ecosystems had stronger carbon uptake capacity, water regulatory potential, and environmental stability than dune ecosystems. The three methods yielded highly consistent &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; for both dune (&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;EF&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;: 0.0676, &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;Cov&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;: 0.0564, &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;corr&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;: 0.0544 m³/m³) and meadow (&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;EF&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;: 0.4335, &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;Cov&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;: 0.4178, &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;corr&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;: 0.3934 m³/m³) ecosystems, with standard deviations of 0.005 and 0.023 m³ /m³ , respectively. In dunes, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; was primarily driven by rainfall (Rain) and evapotranspiration (ET), with gross primary productivity (GPP) and ET jointly contributing over 50 % to its formation. In meadows, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;t&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; was regulated by Rain and canopy conductance (gc), with GPP and gc contributing 28.98 % and 19.57 %, respectively. As shown fo","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"326 ","pages":"Article 110235"},"PeriodicalIF":6.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147386128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}