Heavy metal pollution in groundwater poses global environmental and public health risks, particularly in agricultural regions relying on groundwater for irrigation and drinking. Here we quantify 11 heavy metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Cd, Ba) in the Fengpei Plain, China, and apportion their sources and health impacts using the APCS-MLR receptor model coupled with health risk assessment. Mean concentrations ranked as: Sr (521.5 μg/L) > Ba (50.45 μg/L) > Fe (15.37 μg/L) > As (1.080 μg/L) > Zn (0.887 μg/L) > Cu (0.294 μg/L) > Cr (0.083 μg/L) > Ni (0.064 μg/L) > Co (0.032 μg/L) > Mn (0.027 μg/L) > Cd (0.011 μg/L). Source apportionment using the APCS-MLR model revealed five major sources of heavy metals in the study area, with their respective contributions as follows: iron ore mining (22.8

Runoff is a fundamental component of the hydrological cycle and a key indicator of water security. Its dynamics are jointly shaped by climate change (CC) and human activities (HA). However, the spatiotemporal evolution of pixel-scale runoff and the relative contributions of its drivers remain poorly constrained across large spatial extents and long-term periods. Drawing upon multi-source data of precipitation (P), potential evapotranspiration (PET), underlying surface conditions (n), and runoff volume from 1980 to 2024, this research integrates trend analysis, abrupt change detection, water balance, and the Budyko model to illuminate the spatiotemporal dynamics of runoff at a pixel scale in China, and further quantifies the underlying driving mechanisms and contribution shares of CC and HA to runoff alterations. The results showed that natural runoff (RN) increased significantly across China during 1980–2024 at a rate of 1.70 mm yr-1, with 64.98% of the country exhibiting significant increases. In contrast, actual runoff (RM) declined significantly at a rate of 1.57 mm yr-1, with significant decreases observed across 73.61% of the study area. This nationwide divergence suggests that increasing anthropogenic influences, particularly human water consumption, progressively offset the hydrological gains associated with increasing RN. Abrupt changes in RM exhibited pronounced temporal clustering and spatial heterogeneity, with 2019 representing the most widespread change-point year and accounting for 8.79% of all detected abrupt changes. The strong spatial correspondence between change-point hotspots and regions of intensive water consumption further highlights the increasing influence of anthropogenic disturbances on hydrological dynamics. Runoff variations in China were jointly regulated by CC and HA, with contribution rates of 46.44% and 53.56%, respectively, indicating a transition toward anthropogenic dominance in runoff regulation. Among the climatic factors, precipitation was the dominant driver of runoff variability, contributing 32.46%, substantially exceeding the influence of PET. Among the anthropogenic factors, human water consumption emerged as the dominant contributor to runoff decline, accounting for 49.90% of the observed changes. These findings demonstrate that increasing anthropogenic water consumption has fundamentally altered runoff dynamics across China and provide important scientific support for adaptive water-resource management, optimized water allocation, and sustainable watershed governance under growing water demand and climate change.

To address the issue of freshwater scarcity for agricultural irrigation in arid and semi-arid regions, saline water and reclaimed water have great potential as alternative irrigation water. Therefore, a three-year field study was conducted in the Yinbei Irrigation District of Ningxia, China, to investigate the effects of alternate drip irrigation using freshwater (F), saline water (S) and reclaimed water (R) on sunflower growth. The study established six alternate drip irrigation schedules (SSR, SRS, RSS, SRR, RSR, RRS) and three continuous drip irrigation modes (FFF, SSS, RRR) based on the key sunflower growth stages: emergence-budding, budding-flowering, and flowering-maturity. The results revealed that during the emergence-budding stage and budding-flowering stage, saline water irrigation favored the allocation of dry matter to the roots, whereas reclaimed water irrigation was more effective in allocating dry matter to the leaves and faceplate, and significantly promoted nitrogen and phosphorus accumulation in sunflower plants. Furthermore, reclaimed water irrigation dramatically increased the crude protein content (12.6 %-15.4 %), unsaturated fatty acid content, and saturated fatty acid content in sunflower grains. During the flowering-maturity stage, reclaimed water irrigation was more conducive to dry matter accumulation in the plant, biomass allocation to the faceplate and grains, and resulted in an increase in sunflower grain yield by 2.1 %-5.0 %. Additionally, reclaimed water irrigation during the flowering-maturity stage significantly promoted radial development of the sunflower faceplate and markedly increased the linoleic acid and palmitic acid contents in the kernels, compared to saline water irrigation. The optimal irrigation schedule for sunflower cultivation in arid and semi-arid agricultural areas of China was suggested to be alternate irrigation with saline water during the emergence-budding stage and reclaimed water during the budding-flowering stage and flowering-maturity stage.

Terraced fields represent unique agricultural ecosystems in southwestern China, where soil exhibits preferential flow, potentially leading to the loss of water and fertilizers in rice paddies, thus affecting the structural stability of field ridges. However, the understanding of preferential flow characteristics in paddy and ridge soils across different altitudes remains limited. This study investigates the distribution and development of preferential flow in paddy fields and ridges at low, middle, and high elevations within the Hani terraced paddy fields. The results indicate significant variations in soil moisture infiltration with elevation. Preferential flow was predominantly observed in the shallow layers, particularly in the middle elevation areas, where the stained area ratio (SAR) and stained path number (SPN) reached their peaks. The preferential flow ratio (PFfr) was highest at mid-elevations, with values of 50.97 % for rice fields and 97.33 % for ridges, suggesting a more advanced preferential flow in the latter. Additionally, lateral preferential flow from paddy fields to ridges was significant. Key environmental factors, including soil bulk density, total porosity, and organic matter, were found to correlate with preferential flow indicators. In conclusion, variations in soil properties significantly influence water movement, with mid-elevation regions exhibiting greater soil moisture infiltration. To mitigate water loss and prevent ridge collapse, strategies such as loosening paddy fields and adjusting irrigation and fertilization practices are recommended. These findings contribute to enhanced water dynamics and resource management in both natural and modified ecosystems.

Large soil pores critically influence water and solute transport in soils. The presence of preferential flow paths created by soil macropores can profoundly impact water quality, underscoring the necessity of accurately assessing the characteristics of these macropores. However, it remains unclear whether variations in macropore structure exist between different altitudes and positions of terraced paddy fields. The primary objective of this research was to utilize X-ray computed tomography (CT) and image analysis techniques to characterize the soil pore structure at both the inner field and ridge positions across different altitude levels (high, medium, and low altitude) within terraced paddy fields. The results indicate that there are significant differences in the distribution of large soil pores at different altitudes, with large pores concentrated in the surface layer (0–10 cm) in low-altitude areas, while in high-altitude areas, the distribution of large pores is more uniform. Additionally, as altitude increases, the porosity of large pores shows an increasing trend. The three-dimensional equivalent diameter and large pore volume are primarily characterized by large pores ranging from 1 to 2 mm and 0 to 5 mm3, respectively, with their morphology predominantly appearing spherical or ellipsoidal. The connectivity of large pores in the surface layer of paddy soil is stronger than that in the bunds. However, this connectivity gradually weakens with increasing soil depth. The findings from this study provide valuable quantitative insights into the unique characteristics of soil macropores that vary according to the altitude and position in terraced paddy fields. Moreover, this study emphasizes the necessity for future research that encompasses a broader range of soil types, altitudes, and terraced paddy locations to validate and further explore the identified relationships between altitude and macropore characteristics.

Scientific irrigation scheduling is crucial for conserving agricultural water resources, as excessive irrigation diminishes crop yield and imprecise water application can equally reduce water use efficiency (WUE). In Western Liaoning Province, China, where water scarcity is critical, traditional irrigation regimes are commonly used for peanut cultivation, with local farmers applying water without considering actual crop water demands, thereby reducing water efficiency and yield. In this study, field experiments on peanuts were conducted from May to October during 2021 and 2022 in Heishan County, Western Liaoning Province, China. Four irrigation regime treatments for micro-sprinkler irrigation, with different lower limits of soil water content, were applied: T1 (55% field capacity), T2 (65% field capacity), T3 (75% field capacity), and T4 (85% field capacity). The plant height, stem thickness, root length, dry matter weight, yield, WUE, and net return were measured. Different irrigation regimes had significant effects on peanut growth. The yield was highest in the T3 treatment in 2021 at 5574 kg·hm−2. Moderate irrigation could improve the yield, but it was difficult to simultaneously achieve a high WUE. The WUE of the T3 treatment was 5% lower than that of the T2 treatment in 2022, where the WUE was the highest at 1.62 kg·m−3. The highest net return was observed in the T3 treatment at 27,307 yuan·hm−2. The T3 treatment, with the highest similarity degree of 0.83 as determined with the entropy value and TOPSIS method, was evaluated as the optimal irrigation regime. This regime not only exhibited a favorable balance of water use efficiency and yield but also maximized economic benefits, making it a recommendable practice for local peanut irrigation.

With the rapid development of the social economy, human activities have increasingly disrupted water environments, and the continuous input of pollutants poses significant challenges for water environment management. Taking the Xiaoxingkai Lake basin as the study area, this paper develops a social–economic–water environment model based on the system dynamics methodology, incorporating subsystems for population, agriculture, and water pollution. The model focuses on four key indicators of pollution severity, namely, total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), and ammonia nitrogen (NH3-N), and simulates the changes in pollutant loads entering the river under five different scenarios from 2020 to 2030. The results show that agricultural non-point sources are the primary contributors to TN (79.5%) and TP (73.7%), while COD primarily originates from domestic sources (64.2%). NH3-N is mainly influenced by urban domestic activities (44.7%) and agricultural cultivation (41.2%). Under the status quo development scenario, pollutant loads continue to rise, with more pronounced increases under the economic development scenario, thus posing significant sustainability risks. The pollution control enhancement scenario is most effective in controlling pollutants, but it does not promote socio-economic development and has high implementation costs, failing to achieve coordinated socio-economic and environmental development in the region. The dual-reinforcement scenario and moderate-reinforcement scenario achieve a balance between pollution control and economic development, with the moderate-reinforcement scenario being more suitable for long-term regional development. The findings can provide a scientific basis for water resource management and planning in the Xiaoxingkai Lake basin.

With the rapid expansion of the aquaculture scale, the environmental pollution caused by the accumulation of fish pond sediment (FPS) has become increasingly prominent, making it urgent to establish sustainable resource utilization solutions. This study investigates the potential of using FPS as a soil amendment to improve saline–alkali soil (SAS) quality and enhance vegetable growth, while also quantifying ecological benefits through Gross Ecosystem Product (GEP) accounting. A pot experiment was conducted to evaluate the effects of different FPS mass percentages (0%, 20%, 40%, 80%, and 100%) on the growth of three vegetables (water spinach, lettuce, and chili) and soil quality. The results demonstrated that FPS addition at ≥40% significantly improves SAS quality, reducing the pH and salinity (p < 0.05), while enhancing organic matter, nutrient availability, and microbial activity. Among the treatments, 80% FPS maximized vegetable yields, with water spinach achieving the highest edible biomass (37.32 g). Compared to the control, nutritional quality under ≥80% FPS treatment showed substantial increases: vitamin C (133.33–307.03%), soluble sugars (49.97–73.53%), and protein (26.14–48.08%). An economic analysis revealed that 80% FPS with water spinach cultivation generated peak ecological benefits (274,951 CNY·ha−1; 185% above control). These findings provide a scientific basis and effective model for the resource utilization of FPS and the improvement of saline–alkali soil, offering significant implications for the sustainable development of agriculture and environmental protection.

The improved multi-stage drip irrigation scheduling, combined with agronomic engineering, was successfully applied for spring re-vegetation in coastal saline soils. To date, few studies have addressed summer vegetation planting using this method. The aim of this study is to reveal the desalinization mechanism associated with summer afforestation and multi-stage drip irrigation. A three-year field experiment was conducted in the coastal saline land of southern China. The trial consisted of four irrigation stages, with the soil moisture potential (SMP) monitored directly beneath the drip emitter at a depth of 0.2 m, correspondingly controlled to be higher than −10 kPa (Stage I), −25 kPa (Stage II), and −45 kPa (Stage III), respectively. Results indicated that soil bulk density decreased by 14%, while soil moisture increased by 30% compared to initial conditions. The average electrical conductivity (EC) value across the entire soil layer decreased by 65.64% to 97.79%. Soil pH gradually increased during the first three irrigation stages, with the rate of increase accelerating during the rainfed stage, reaching values between 9.22 and 9.87. The concentrations of soil ions, including Ca2+, K+, Mg2+, Na+, and SO42−, decreased by 95.18%, 79.67%, 87.74%, 89.68%, and 57.19%, respectively, in the final irrigation stage. Throughout the entire soil profile, the average sodium adsorption ratio (SAR) decreased by 49.37%, while the average exchangeable sodium percentage (ESP) increased by 9.98%. This study demonstrated that multi-stage drip irrigation scheduling significantly influenced the soil physicochemical properties, soil salt ions, and vegetation growth, and thereby explained the efficient desalinization mechanism associated with this irrigation strategy. It is recommended to increase the amount of irrigation water and apply acidic regulators during the rainfed stage to reduce soil pH for vegetation establishment in coastal saline areas.

Preferential infiltration is prevalent in low-hilly areas and has a significant influence on soil hydrological processes. Changes in land use are widely acknowledged as factors that affecting preferential infiltration. Nevertheless, the influence of prolonged vegetation restoration on soil permeability and the development of preferential flow remains inadequately understood. In this study, the dye tracer method and laboratory experiments were adopted to quantitatively assess disparities in the physicochemical properties of soils and their effects on the development of preferential flow and soil permeability among the three land types in typical low-hilly areas. The findings suggest that (1) forest and dry land show a higher soil infiltrability than paddy fields, with stable-state infiltration rates at depths of 0–20 cm and 20–40 cm being elevated by 43.52–73.15

Facing the dual challenges of an energy crisis and climate warming, this paper introduces an integrated uncertain optimization framework for sustainable agricultural crop and livestock management under waste-to-energy nexus, aiming at maximizing bioenergy production, economic profit, and minimizing allocation risks, nitrogen, phosphorus, and carbon footprints. The framework addresses return-risk tradeoffs, decision-making attitudes, and uncertainties in agricultural systems; reconciles conflicting objectives among energy, economic, and environmental spheres; identifies bioenergy potentials from crop and livestock management; and validated through a case study in Hubei province, China. Flexible resource allocation schemes answer questions commonly asked by decision makers: "Where are the bioenergy production potentials from agricultural wastes?" and "Which efforts will lead to better agricultural sustainability?". Compared to current practices, optimal results show increased economic profits by 5.07 x 108 CNY, reduced allocation risks by 5.02 x 108 CNY, reduced environmental impacts by 0.89 x 108 kg N, 0.26 x 106 kg P, and 0.37 x 1010 kg CO2, and significant bioenergy potential 2.304 x 1011 MJ contributed by crop straw and livestock manure recycling. The proposed model performed well in generating robust and coordinated solutions. This study offers an optimization-based solution towards sustainable energy transition and global warming mitigation, as well as valuable insights for other systems suffering similar energy and environmental crises.

Emergy theory and methodology have been widely applied in the study of ecosystems and sustainability. This article employs bibliometric methods and visualization tools (SATI, VOSviewer and CiteSpace) to conduct a systematic statistical analysis of 1,404 emergy-related articles retrieved from the Web of Science database. The results are as follows: 1) Overall, the annual publication volume demonstrates a consistent upward trajectory. China exhibits dominant contributions across all levels—national, institutional, and individual authorship. 2) Emergy-related papers are mainly published in high - quality journals, concentrated in environmental and ecological sciences, especially in themes related to ecosystems, the geobiosphere, sustainable development, and sustainability assessment. 3) Against the backdrop of rapid population growth and climate change, emergy theory has been applied and developed in the field of sustainable development. Emergy research not only explores ways to reduce the impact of human activities on climate change but also provides quantitative tools for decision-makers in combination with a variety of theoretical approaches to promote sustainable evaluation of emerging technology systems. These themes are expected to remain key focuses in emergy research. Additionally, the integration of emergy with emerging fields such as Artificial Intelligence (AI) shows great potential. 4) Emergy research still faces issues like methodological disputes, data dependency, and insufficient dynamic modeling capabilities. There’s an urgent need to address these challenges, by establishing a standardized methodological framework, developing AI-integrated dynamic models, promoting cross-disciplinary/cross-national cooperation, and advancing the cross-application of bibliometrics and meta-analysis.

River pollution is a major issue in China’s urbanization process. Understanding the effects of river morphology and constructed wetlands on the self-purification capacity is crucial for water quality improvement. This study takes the Shiwuli River, a main tributary of Chaohu Lake, as an example. By monitoring the concentration changes of five water quality indicators—total nitrogen (TN), total phosphorus (TP), ammonia nitrogen (NH3-N), chemical oxygen demand (COD), and dissolved oxygen (DO)—in the river section for the years 2017 and 2024, we conducted a comparative analysis of the relationship between river morphology and self-purification capacity, as well as influencing factors. The results show that meandering rivers possess self-purification capabilities under natural conditions. There is a positive correlation between river sinuosity and the reduction rates of TP, TN, NH3-N, and COD, as well as the increase rate of DO—the greater the sinuosity, the stronger the purification capacity. Wetlands enhance both the self-purification capacity and the purification rate of river channels, reducing the required sinuosity for effective self-purification from 1.49 to 1.30. This study also discusses the mechanisms by which meandering rivers influence water self-purification, and proposes that increasing river sinuosity and constructing wetlands can enhance the self-purification capacity. This measure will increase the length and width of the river, prolong the purification time, improve the DO level, and enhance the exchange between the riverbed and groundwater. The findings of this study can provide a reference for river restoration and management in the context of urbanization.

Understanding groundwater recharge origin and hydrochemical evolution processes is imperative for sustainable groundwater management, particularly in vulnerable river-lake basins. In this study, natural-human factors controlling groundwater chemistry evolution in the southeast of Nansi Lake Basin (SNLB) were identified by combining self-organizing maps (SOM) with an integrated dataset of hydrochemistry and environmental isotopes (delta 18O and delta 2H). The shallow groundwater samples were classified into 5 clusters by k-means clustering in the SOM, which revealed different isotopic and hydrochemical characteristics. The relationship between delta 18O and delta 2H in different water bodies indicates that atmospheric precipitation is the primary recharge source for groundwater in the eastern lake area, with some contribution from deep groundwater leakage. In contrast, the hydrogen and oxygen isotope composition of groundwater in the western lake area is significantly more depleted than local precipitation, suggesting that it may be recharged by external water sources. The groundwater samples east of Nansi Lake (Cluster 1-2) were characterized by Ca-HCO3 and Ca center dot Mg-HCO3 center dot SO4 type with relatively low pH, TDS, and F- , but high NO3- concentration. However, the groundwater in the area west of Nansi Lake (Cluster 3-5) represented Na center dot Mg-HCO3 center dot Cl and Na center dot Mg-Cl center dot HCO3 type with higher pH, TDS, Na+, HCO3- , and F- concentration, along with less NO3- contamination. On the east side of Nansi Lake, the primary ion concentrations of groundwater were mainly derived from carbonate weathering and anthropogenic NO3 - input. The ionic ratio diagram indicated that NO3 - contamination is primarily from agricultural activities and domestic sewage. Contrarily, multiple natural processes, including silicate weathering, evaporite dissolution, cation exchange, and geogenic sources' F- were responsible for groundwater chemistry on the west side of Nansi Lake. The dissolution of fluoride-bearing minerals, carbonate precipitation, and positive cation exchange jointly controlled groundwater F- enrichment. The findings of this study imply that SOM is an effective tool for dealing with highdimensional data to understand groundwater's origin and evolution patterns better.

Ningxia is one of the main tomato-planting regions in China, but unreasonable irrigation modes and excessive fertilization rates have restricted the efficient development of local agriculture. Field experiments were carried out during 2019-2020 in Yinbei Irrigation District of Ningxia, China, to investigate the coupling effects of different micro-nano aeration ratios and topdressing levels on tomato growth and development, with underground drip irrigation system. The aeration ratios consist of non-aeration (0), low aeration (5 %), medium aeration (10 %) and high aeration (15 %). The topdressing levels of urea-tricalcium superphosphate-potassium sulfate included high topdressing (180-400-480 kg center dot ha-1 , traditional level), medium topdressing (135-300-360 kg center dot ha-1 ) and low topdressing (90-200-240 kg center dot ha-1 ). Results indicated that increasing the aeration ratio stimulated root viability and the development of fine root (diameter in 0-2 mm) to moderate root (diameter in 2-5 mm); raised leaf net photosynthetic rate, single fruit weight and tomato yield; and promoted the accumulation of organic acid, vitamin C, soluble sugar and soluble protein in tomato fruits. With the same aeration ratio, decreasing the high topdressing level to medium topdressing level increased single fruit weight and tomato yield, accelerated fruit expansion, promoted soluble solids and soluble sugar accumulation. Besides, increasing the aeration ratio by 10 % or 15 % was enough to alleviate the adverse effects of decreasing the high topdressing level to medium topdressing level. Considering the decrease of topdressing fertilizer application amount, increasing tomato yield and improving fruit quality, the present study suggested that the appropriate topdressing level of urea-triple superphosphate-potassium sulfate and the corresponding proper aeration ratio for tomato underground drip irrigation in the Yinbei Irrigation District of Ningxia was 135-300-360 kg center dot ha-1 and 15 %, respectively. The obtained proper combination of micro-nano aeration ratio and topdressing level can provide a scientific basis for the management of aerated underground drip irrigation and fertilization in northeast Ningxia of China and other agricultural districts with similar environments.

Water quality degradation and eutrophication of lakes are global ecological and environmental concerns, especially shallow lakes. This study collected hydrochemical data from 2935 samples of the Chinese part of Xingkai (Khanka) Lake, based on 40 published papers spanning the period from 2001 to 2023. Using the water quality index (WQI), improved geo-accumulation index (Igeo), and redundancy analysis (RDA), we analyzed the overall contamination characteristics of the water environment in Xingkai Lake. Additionally, we explored the impact of climate change and human activities on the lake’s water quality. The results showed that the annual WQI for Xingkai Lake ranged from 47.3 to 72, with a general downward trend, indicating improving water quality. Notably, the average WQI in May and total nitrogen (TN) content decreased significantly, signaling further improvement in water quality. The average concentration of TN in sediments was 1401.3 mg/kg, reflecting mild contamination. The Igeo values for the heavy metals Hg and Cr were greater than 1, indicating moderate contamination, while the Igeo values for Cd and Pb were between 0 and 1, which is in the range of uncontaminated to moderately contaminated. Land use and climate change (average annual temperature and annual precipitation) were key factors influencing water quality, with cumulative explanatory ratios of 67.3% and 50.1%. This study utilized land-use change as a metric for human activities, highlighting the potential impacts of climate change and human activities on the water quality of Xingkai Lake. It offers vital insights for the sustainable management of Xingkai Lake and provides valuable references into the management of similar transboundary lakes.

The intensified development of aquaculture and excessive use of agricultural fertilizers pose a threat to natural resource availability and deteriorate the environment. Utilizing aquaculture wastewater from mariculture for agricultural irrigation can mitigate pollution and alleviate the pressure on natural resources. This study investigated the comprehensive benefits of using freshwater and mariculture wastewater for irrigation, employing two concentration levels of mariculture wastewater in a pot experiment with saline-tolerant rice. Furthermore, we quantitively assessed the integrated benefits for farmland by utilizing an ecosystem service function value assessment and emergy value theory. The results indicate a significant enhancement in the growth and yield of saline-tolerant rice when irrigated with mariculture wastewater. Specifically, the theoretical yield increased by 9.01% relative to freshwater irrigation. Irrigation using aquaculture wastewater significantly enhanced the nutrient concentrations in the soil, including soil organic carbon (SOC), avail-K (AK), Olsen-P (OP), and alkali-N (AN). Additionally, the uptake of these nutrients by salt-tolerant crops during their late reproductive stage effectively mitigated the rise in soil salinity induced by the wastewater irrigation practice. Under experimental conditions, wastewater irrigation conferred superior ecological benefits compared with freshwater irrigation. The comprehensive benefits of wastewater irrigation, valued at 104,439.10 RMB/hm2, exceeded those of freshwater irrigation by 188.8%. The utilization of mariculture wastewater effectively enhances the coastal environment, augments crop yields, and diminishes treatment costs. From the perspectives of revenue enhancement, environmental compatibility, and sustainability, the model of utilizing salt-tolerant crops irrigated with mariculture wastewater holds substantial promotional and practical significance.

Water delivery management in China’s irrigation districts has traditionally prioritized the main canal system, often overlooking the water-saving potential of the final canals and field irrigation, which offer substantial opportunities to enhance water use efficiency and conserve agricultural water resources. This study summarizes and defines the integrated water management of final canals and field irrigation as terminal water management. An optimization method was developed to improve terminal water management, which includes optimizing irrigation quotas based on water balance and scheduling final canal water delivery to minimize seepage losses. A genetic algorithm was employed to solve the problem. The method was applied to the Hongjin irrigation district in Jiangsu Province, China. In 2020, paddy water management was observed, revealing that the irrigation amount for organic and traditional rice was 1113 mm and 956 mm, respectively. Conventional irrigation and water delivery practices have led to extensive drainage, significant rainwater wastage, and inefficient water use. The optimized irrigation quotas for organic and traditional rice resulted in water savings of 302.5 mm and 325.9 mm, respectively, compared to the 2020 monitored data. An irrigation event in early August during a 75% hydrological frequency year was selected as an example. With conventional scheduling, optimized final canal water delivery scheduling reduced the seepage losses from 6.3% to 4.6%, shortened the irrigation time from 17 h to 14 h, and stabilized canal flow rates. The proposed optimization method is a valuable tool for enhancing terminal water management and supporting better irrigation decisions in irrigation districts.