Agricultural Water Management最新文献

{"title":"Enhancing rice yields, water productivity, and profitability through alternate wetting and drying technology in farmers’ fields in the dry climatic zones of West Africa","authors":"Jean-Martial Johnson ,&nbsp;Mathias Becker ,&nbsp;Elliott Ronald Dossou-Yovo ,&nbsp;Kazuki Saito","doi":"10.1016/j.agwat.2024.109096","DOIUrl":"10.1016/j.agwat.2024.109096","url":null,"abstract":"<div><div>Irrigated rice farming is crucial for meeting the growing rice demand and ensuring global food security. Yet, its substantial water demand poses a significant challenge in light of increasing water scarcity. Alternate wetting and drying irrigation (AWD), one of the most widely advocated water-saving technologies, was recently introduced as a prospective solution in the semi-arid zones of West Africa. However, it remains debatable whether AWD can achieve the multiple goals of saving water while increasing yield and farmer income in diverse edaphic and climatic growing environments. We carried out participatory on-farm trials in four major irrigation schemes of Burkina Faso, (i) to assess the effects of AWD on yield, water productivity, and profitability in comparison to farmers’ irrigation practices, and (ii) to identify the environmental conditions and cropping practices determining yield gain of AWD over farmers’ irrigation practices. During the 2018 and 2019 wet and dry seasons, we conducted 154 pairwise comparisons of AWD at the threshold of 15 cm below the ground surface, and farmers’ irrigation practices (fields being submerged as frequently as water availability allowed according to the scheme-dependent water provision schedule). The drivers of yield gains associated with AWD were identified using brute force and random forest machine learning algorithms. Across irrigation schemes and seasons, AWD reduced irrigation water input by 30 %, while increasing grain yield by 6 % (<em>p</em> &lt; 0.05). Consequently, AWD increased the irrigation water productivity by 64 % and profit by 5 % over farmers’ irrigation practices. The AWD-associated yield gains were higher in fields with poor access to irrigation water, and higher for <em>indica</em> than for tropical <em>japonica</em> varieties. Overall, AWD appears to be an effective strategy to improve yields, water productivity, and profitability in rice irrigation schemes in dry climatic zones in West Africa. This study suggests a need for reshaping rice irrigation practices, involving a systematic monitoring of field water levels in the region.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"304 ","pages":"Article 109096"},"PeriodicalIF":5.9,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"UAV-enabled approaches for irrigation scheduling and water body characterization","authors":"Manish Yadav ,&nbsp;B.B. Vashisht ,&nbsp;Niharika Vullaganti ,&nbsp;Prem Kumar ,&nbsp;S.K. Jalota ,&nbsp;Arun Kumar ,&nbsp;Prashant Kaushik","doi":"10.1016/j.agwat.2024.109091","DOIUrl":"10.1016/j.agwat.2024.109091","url":null,"abstract":"<div><div>In recent years, precision agriculture has seen a substantial increase in the use of unmanned aerial vehicles (UAVs). They have shown great potential in spraying, nutrient application, irrigation scheduling, field mapping, yield estimation, and crop monitoring. UAV-enabled approaches have transformed several industries, and they have enormous potential for irrigation water management and characterization of water reservoirs. This paper explores the use of UAVs for variable rate irrigation (VRI) which provides tailored irrigation based on crop water demand, weather conditions, and soil moisture levels using the indices <em>viz</em> canopy temperature, crop water stress index (CWSI), crop evapotranspiration, etc. UAV-VRI provides customized irrigation which increases crop yield and reduces total water uses by improving the water use efficiency. It further enables sustainable water resources management, particularly in water-scarce areas. UAVs offer versatile applications including mapping water quality, vegetation, and bathymetry of aquatic bodies such as lakes and reservoirs. The review highlights the advantages of UAVs over conventional techniques, including a cost-effective, high spatial and temporal resolution, frequent revisit time for irrigation scheduling and monitoring of water bodies which provide useful information for water resource managers and environmental researchers. However, It also discusses the challenges associated with UAVs such as legal issues, data processing, and the need for trained personnel. The massive amounts of data gathered by UAVs may be processed and analyzed using machine learning algorithms, enabling more effective and precise water management. The ongoing advancements in UAVs and machine learning ensure its potential for sustainable water resources management.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"304 ","pages":"Article 109091"},"PeriodicalIF":5.9,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microplastics in aquaculture environments: Sources, pollution status, toxicity and potential as substrates for nitrogen-cycling microbiota","authors":"Pei Su ,&nbsp;Jianhui Chang ,&nbsp;Fei Yu ,&nbsp;Xugan Wu ,&nbsp;Gaohua Ji","doi":"10.1016/j.agwat.2024.109090","DOIUrl":"10.1016/j.agwat.2024.109090","url":null,"abstract":"<div><div>Microplastics (MPs) have emerged as a pressing global pollution issue and have drawn significant attention in the field of environmental science in recent years. Plastics are widely used in aquaculture, leading to the accumulation of MPs in aquaculture environments, referred to as aquaculture-derived MPs (AD-MPs). This review summarizes the pollution status of MPs in aquaculture environments, their adverse impacts on aquaculture, and the potential benefits of MPs serving as substrates for nitrogen-cycling microbiota to improve water quality in aquaculture. Our study underscores the severity of microplastic pollution in aquaculture, with the microplastic content reaching 362.8 items L⁻¹ in water and up to 124,884 items kg⁻¹ in sediment. However, these levels vary significantly depending on the type of aquaculture system and the specific location of aquaculture activities, with MPs being most abundant in estuary aquaculture systems. The primary sources of MPs in aquaculture environments include plastic nets, packaging and other plastic tools used in aquaculture. Consequently, most of the MPs present are white fibers composed of polypropylene and polyethylene. These MPs accumulate in aquatic products such as fish, shrimp, crabs, and shellfish, with abundances reaching 61.75 items per individual. This accumulation leads to toxic and combined effects on cultured animals and poses a risk to human health through the food chain. However, the surfaces of MPs (the plastisphere) also facilitate a series of chemical reactions, including biological nitrogen fixation, nitrification and denitrification, by serving as a substrate that attracts nitrogen-cycling microorganisms. These findings highlight the potential positive effects of MPs in aquaculture. To mitigate the ecological risks arising from MPs in aquaculture and address their potential threats to human health, it is essential to conduct long-term, sustainable assessments of MPs in aquaculture water sources. Special attention needs to be given to the effects of nitrogen-cycling biofilms on the surface of MPs and their potential benefits to aquaculture water quality.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"304 ","pages":"Article 109090"},"PeriodicalIF":5.9,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring expert perceptions towards emerging pollutants and their impacts in reused wastewater and agriculture","authors":"Antonio Jodar-Abellan ,&nbsp;José Antonio Albaladejo-García ,&nbsp;Pablo Aznar-Crespo ,&nbsp;Manuel Ballesta de los Santos ,&nbsp;Seyed Babak Haji Seyed Asadollah ,&nbsp;Abdessamed Derdour ,&nbsp;Juan José Martínez-Nicolás ,&nbsp;Pablo Melgarejo ,&nbsp;Daniel Prats ,&nbsp;Francisco Serrano-Bernardo","doi":"10.1016/j.agwat.2024.109098","DOIUrl":"10.1016/j.agwat.2024.109098","url":null,"abstract":"<div><div>Water sustainability involves several natural and human spheres conditioning the availability and quality of water resources and life conservation. Regarding water quality, currently emerging pollutants (EPs) are a key topic at global scale since they are difficult to remove by traditional water treatment systems. In this context, this work aims to evaluate experts’ perception of several EPs issues with a special focus on semi-arid Mediterranean areas where EPs are negatively impacting water, environmental, and agricultural systems as, in these areas, effluents from water treatment plants are widely reused in the irrigation of crops, urban gardens, and golf courses or directly discharged on natural streams. Particularly, a detailed survey composed of questions about EPs regulation, risk insight, equipment, social and economic impacts, was performed collecting 437 responses. Main results suggested that EPs existence may pose a significant risk and a destabilizing factor in wastewater reuse, with negative impacts to crop irrigation, being managers the class with more concern followed by scientifics and administratives. New EPs regulations raises uncertainty amongst experts since 29 % considered positive its creation, while 20 % estimated this fact as regular and 14 % as negative. As well, although the combination of technologies to improve EPs removal generated agreement, aspects like the treatment charges at water treatment plants or the price/bill of EPs-free water were features of ambiguity. Within EPs elimination, the three expert groups highlighted that technologies impacts in the sustainability spheres will be positive on public health (87 % of responses), social trust (75 %), and environmental sustainability (76 %). Likewise, 88 % of experts concurred that the future of wastewater reuse relies on a combination of technologies. These findings offer valuable information to water legislators and policymakers to manage water resources, especially in semi-arid areas due to the final use of treated effluents and, therefore, the great implications for agriculture, environment and human health.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"304 ","pages":"Article 109098"},"PeriodicalIF":5.9,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rainfall water collection and irrigation via stone bud and karren on karst rocky desertification slopes: Application and benefit analysis","authors":"Baichi Zhou ,&nbsp;Shengtian Yang ,&nbsp;Hezhen Lou ,&nbsp;Jiyi Gong ,&nbsp;Zihao Pan ,&nbsp;Huaixing Wang ,&nbsp;Yin Yi ,&nbsp;Chengcheng Gao ,&nbsp;Xueyong Huang ,&nbsp;Weizhao Wu","doi":"10.1016/j.agwat.2024.109087","DOIUrl":"10.1016/j.agwat.2024.109087","url":null,"abstract":"<div><div>Lack of surface water is a key factor leading to agricultural drought in karst regions and exacerbates the karst rocky desertification, which is characterized by high rate of exposed bedrock. With the characteristics of impermeability, runoff collection, and wide distribution, stone bud and karren (SBK), a unique karst landscape type composed of exposed bedrock and gullies, has a great potential to solve water shortage in agricultural irrigation, especially in the rain-rich karst regions of Guizhou Province, China. Using unmanned aerial vehicle images to identify SBK and measured rainfall–runoff data for validation, we applied SBK as a basic unit to harvest rainfall water on rocky desertification slopes and analyzed the benefits of rainfall water collection and irrigation via SBK. The results showed the following: (1) Karrens on rocky desertification slopes could be identified using a method coupling terrain opening difference and depression filling, and the simulated runoff on SBK could achieved the average <em>NSE</em> and <em>R</em>^<em>2</em> of 0.82 and 0.86, with <em>RMSE</em> and <em>RSR</em> less than 0.03 m³ and 0.51, respectively. (2) The exposed bedrock utilization rate and rainfall water collection coefficient of SBK were 0.62 and 0.55, respectively, such that the area ratio of exposed bedrock to the cultivated land meeting irrigation water demand reached 1:3.1, 1:3.7 and 1:7.0 under 90 %, 80 % and 50 % possibilities of irrigation. (3) Implementing SBK for rainfall water harvesting and irrigation could efficiently avoid crop failure in the karst regions where crops faced drought within only one week after rainfall, and was at an affordable cost to local farmers with limited environmental damage. The use of SBK to harvest rainfall water could also alleviate surface water shortages in karst regions caused by problems such as uneven temporal distribution of rainfall and engineering water shortages. Consequently, SBK demonstrate a strong application potential to alleviate agricultural drought in karst rocky desertification regions.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"304 ","pages":"Article 109087"},"PeriodicalIF":5.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of long-term biodegradable film mulching on yield and water productivity of maize in North China Plain","authors":"Xiudi Shangguan ,&nbsp;Xin Wang ,&nbsp;Meng Yuan ,&nbsp;Mingliang Gao ,&nbsp;Zhendong Liu ,&nbsp;Ming Li ,&nbsp;Rui Zong ,&nbsp;Chitao Sun ,&nbsp;Mingming Zhang ,&nbsp;Quanqi Li","doi":"10.1016/j.agwat.2024.109094","DOIUrl":"10.1016/j.agwat.2024.109094","url":null,"abstract":"<div><div>Biodegradable films are considered ideal alternatives to polyethylene films because of their advantages in increasing crop yield and controlling soil pollution. However, the influences of biodegradable film mulching on soil physicochemical environments and water productivity after long-term mulching remain poorly understood. Therefore, a field experiment after long-term mulching (since 2016) was conducted to explore the effects of black biodegradable film (BB), transparent biodegradable film (TB), and traditional polyethylene film (PE) on soil physicochemical environments, aboveground biomass accumulation, grain yield, evapotranspiration, and water productivity (WP) of maize in the 2021 and 2022 in the North China Plain. The results showed that polyethylene films and biodegradable films had a similar ability to preserve soil moisture, promote maize growth, reduce evapotranspiration, and increase WP. Moreover, the performances of BB were more equivalent to PE, and there was no significant difference on WP and yield under BB and PE. Compared with traditional flat planting without mulching (CK), BB and PE significantly increased yield (9.5 % and 12.7 % in 2021; 5.25 % and 6.37 % in 2022) and WP (11.54 % and 21.47 % in 2021; 24.28 % and 23.42 % in 2022). Film mulching treatments increased the soil organic carbon sequestration rate, and the content of soil organic carbon, microbial activity, and urease activity in the 0–20 cm soil layer compared with CK. According to structural equation modeling, the increasing soil water storage because of films mulching positively influenced yield by enhancing enzyme activities which were related to soil nutrients. Over all, these results showed that black biodegradable film is an ideal replacement for polyethylene films under long-term mulching conditions because of its comparable agronomic performance and influence on soil physicochemical environments in the North China Plain.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"304 ","pages":"Article 109094"},"PeriodicalIF":5.9,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The relationship of δD and δ18O in soil water and its implications for soil evaporation across distinct rainfall years in winter wheat field in the North China Plain","authors":"Abdoul Kader Mounkaila Hamani ,&nbsp;Junming Liu ,&nbsp;Zhuanyun Si ,&nbsp;Djifa Fidele Kpalari ,&nbsp;Guangshuai Wang ,&nbsp;Yang Gao ,&nbsp;Xiaotang Ju","doi":"10.1016/j.agwat.2024.109092","DOIUrl":"10.1016/j.agwat.2024.109092","url":null,"abstract":"<div><div>Soil evaporation plays a key role in regulating local climate and water loss. Stable isotope ratios of water (²H/¹H and ¹⁸O/¹⁶O) are effective tracers for studying water flux. This study examines three isotope-based indicators deuterium excess (d-excess), the slope of the soil water evaporation line (SEL), and line-conditioned excess (lc-excess) across three wheat growing seasons: wet, ordinary, and dry years. The influencing factors of d-excess, SEL, and lc-excess, respectively, soil, vegetation, and meteorology, were analyzed using various methods. Wheat yields varied significantly, reaching 6.69 t ha⁻¹ in wet years, 8.66 t ha⁻¹ in dry years, and 9.28 t ha⁻¹ in ordinary years. The lc-excess was highest in ordinary years, and d-excess peaked during dry years. A negative correlation between d-excess and SEL slope, and between lc-excess and SEL slope, was observed in dry and ordinary years (P&lt;0.05), but not in wet years (P&gt;0.05). Multivariate regression showed that net radiation (Rn) was the primary factor influencing SEL, contributing 54.19 %, 11.58 %, and 29.27 % in wet, dry, and ordinary years, respectively. Leaf area index (LAI) was the most significant factor affecting lc-excess (37.91 % in wet years, 32.22 % in dry, and 30.92 % in ordinary years). Vapor pressure deficit (VPD) affected d-excess in wet and ordinary years, while air (Ta) and soil temperature (Ts) were key in dry years. Variation partitioning revealed meteorological factors primarily influenced SEL, lc-excess, and d-excess in wet years, while soil, vegetation, and climate interactions had greater effects in dry and ordinary years. The lc-excess, integrating multiple factors, is a better indicator of soil evaporation than SEL.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"304 ","pages":"Article 109092"},"PeriodicalIF":5.9,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term investigation of the irrigation intervals and supplementary irrigation strategies effects on winter wheat in the U.S. Central High Plains based on a combination of crop modeling and field studies","authors":"Farzam Moghbel ,&nbsp;Forough Fazel ,&nbsp;Jonathan Aguilar ,&nbsp;Abolfazl Mosaedi ,&nbsp;Romulo P. Lollato","doi":"10.1016/j.agwat.2024.109077","DOIUrl":"10.1016/j.agwat.2024.109077","url":null,"abstract":"<div><div>Implementing optimized irrigation strategies to achieve acceptable wheat yield while conserving groundwater resources is critical for extensively irrigated regions. Field experiments regarding winter wheat irrigation management were conducted for two growing seasons (2013–2014 and 2014–2015) to calibrate and validate the AquaCrop model. To determine proper parameterization of the AquaCrop model for various data availability conditions, the model performance was tested for calibration based on three different datasets, including a) calibration based on a full irrigation condition (CA 1), b) calibration based on a dryland condition (CA 2), and c) calibration based on diverse irrigation conditions, which included full irrigation, different deficit irrigation levels, and dryland (CA 3). The CA 3 calibration scenario resulted in the model's highest accuracy in simulating biomass, grain yield, total soil water, and seasonal evapotranspiration during the calibration and validation process. However, the model performance was also convenient when calibration based on full irrigation conditions was pursued. The calibrated and validated AquaCrop model based on the CA3 was used to analyze long-term (36-year) irrigation management scenarios for identifying the optimized water-conservative winter wheat irrigation strategies. The long-term analysis emphasized that increasing irrigation intervals from 7 to 15 or 20 days could reduce groundwater withdrawal by 52–64 % while expecting a 14–19 % reduction in grain yield. By implementing one 25 mm irrigation after planting and two 25 mm depth irrigation events at jointing or leaf growth stages, 91 % of Kansas's average winter wheat yield (2.88 tons/ha) could be achieved. During wet years, the 1.2 ton/ha reduction in biomass and 0.27–0.62 ton/ha reduction in grain yield is expected irrespective of irrigation management strategies. Considerable uncertainty was detected in grain yield production during dry years under dryland (rainfed) conditions. The maximum winter wheat production could be achieved under normal years, establishing a balance between precipitation and heat units. Our agro-hydrological analysis revealed that the highest irrigation water use efficiency could be attained by the application of two 25 mm irrigation events at jointing or flag leaf growth stages during normal years, the application of two irrigation events during jointing or heading during wet years, and two 25 mm irrigations at heading or flowering during dry years. The results of this research could be used as a baseline for producers of the U.S. Central High Plains and semi-arid regions with similar climate characteristics to cope with water scarcity in winter wheat production.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"304 ","pages":"Article 109077"},"PeriodicalIF":5.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimating water quality parameters of freshwater aquaculture ponds using UAV-based multispectral images","authors":"Guangxin Chen ,&nbsp;Yancang Wang ,&nbsp;Xiaohe Gu ,&nbsp;Tianen Chen ,&nbsp;Xingyu Liu ,&nbsp;Wenxu Lv ,&nbsp;Baoyuan Zhang ,&nbsp;Ruiyin Tang ,&nbsp;Yuejun He ,&nbsp;Guohong Li","doi":"10.1016/j.agwat.2024.109088","DOIUrl":"10.1016/j.agwat.2024.109088","url":null,"abstract":"<div><div>UAV imaging technology has become one of the means to quickly monitor water quality parameters in freshwater aquaculture ponds. The change of sunlight during a long flight affects the quality of UAV images, which will reduce the accuracy of monitoring water quality. This study aims to propose a method to correct spectral variation during UAV imaging and apply it to detect dissolved organic matter (DOM) concentration and dissolved oxygen (DO) content in freshwater aquaculture ponds. Firstly, a spectral correction method was used to transform UAV-based multispectral images. The spectral data before and after correction was extracted. Secondly, 18 spectral indices before and after correction were constructed. The optimal combination of indices was identified using correlation analysis algorithm. The estimation models of water quality parameters were then constructed and compared using the Random Forest (RF), Support Vector Regression (SVR), and BP neural network (BP) methods. The results showed that the accuracy of estimating DOM concentration using corrected spectral indices was significantly improved compared to pre-correction models, with the highest improvement of 38 % (SVR), the lowest of 23 % (BP), and an average improvement of 31 %. The RF model performed best, achieving R² = 0.81, RMSE = 3.34 mg/L, and MAE = 2.17 mg/L. For DO content estimation, the accuracy of models using corrected spectral indices was also improved significantly, with the highest improvement of 97 % (RF), the lowest of 39 % (SVR), and an average improvement rate of 67 %. The Random Forest model was again optimal, with R² = 0.69, RMSE = 1.97 mg/L, and MAE = 1.47 mg/L. This study indicates that the proposed spectral correction method helps to map the concentration of DOM and DO in freshwater aquaculture ponds with high accuracy using UAV-based multispectral images.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"304 ","pages":"Article 109088"},"PeriodicalIF":5.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the impacts of different degrees of deficit irrigation and nitrogen interactions on assimilate translocation, yield, and resource use efficiencies in winter wheat","authors":"Tingxuan Zhuang ,&nbsp;Syed Tahir Ata-UI-Karim ,&nbsp;Ben Zhao ,&nbsp;Xiaojun Liu ,&nbsp;Yongchao Tian ,&nbsp;Yan Zhu ,&nbsp;Weixing Cao ,&nbsp;Qiang Cao","doi":"10.1016/j.agwat.2024.109089","DOIUrl":"10.1016/j.agwat.2024.109089","url":null,"abstract":"<div><div>Water and nitrogen (N) are recognized as the primary determinants influencing the development and output of winter wheat. They affect the growth of winter wheat not only through their own changes, but also through their interaction. The translocation and accumulation of pre- and post-anthesis assimilates (including dry matter and N) are important physiological processes in winter wheat, which are closely related to the resource use efficiency and yield. However, a dearth of research exists that examines the complex interplay between varying water levels, especially severe water deficit, and N deficiency levels on the growth dynamics of winter wheat. The purpose of this study was to quantify and compare the effects of different degrees of water deficit and N interaction on assimilate translocation, water and N use efficiency and yield of winter wheat. A four-year long-term field experiment conducted under the rain-out shelter including four irrigation and two N levels was launched during 2019–2023. This method avoided the impact of precipitation on water treatment and helped to achieve serious water deficit treatment. The findings indicated that the higher N application improved the wheat's ability by 49.6 % - 362.3 % to utilize the available soil water. The pre- and post-anthesis translocation and accumulation of assimilates (including dry matter and N) in winter wheat increase alongside elevated levels of water and N application, except under severe water deficit treatment. Plants under mild to moderate water deficit were better able to translocate the pre-anthesis assimilates. However, the severe water deficit hindered the re-translocation of assimilates before anthesis. Providing additional N during periods of severe water scarcity leads to a 13.4 % - 44.7 % reduction in water use efficiency (WUE). Furthermore, both the irrigation water use efficiency and WUE diminished by 10.3 % - 60.5 % and 4.5 % - 41.4 % with higher levels of irrigation, while improved by 24.4 % - 48.2 % and 12.6 % - 39.4 % with higher N application rates. Conversely, N partial factor productivity and N use efficiency followed the opposite trend. Similar to WUE, increasing N application under severe water deficit would result in a yield reduction of 38.7 %. The reduction in crop yield resulting from severe water stress was primarily ascribed to the decline in the kernels number per spike (up to 74.9 %), with the reduction in spike number per unit area following closely behind (up to 29.1 %). This integrated approach, combining resource use efficiency with a detailed assessment of assimilate dynamics, provides a holistic view of how water and N management strategies impact winter wheat performance. The findings will offer precise insights for developing targeted irrigation and N scheduling strategies for sustaining both winter wheat production and environmental sustainability.</div></div>","PeriodicalId":7634,"journal":{"name":"Agricultural Water Management","volume":"304 ","pages":"Article 109089"},"PeriodicalIF":5.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}