The agricultural development of reclaimed coastal areas in Jiangsu Province is significantly hindered by high soil salinity and an inadequate irrigation and drainage infrastructure. Optimizing the layout of subsurface drainage systems has been identified as an effective means of reducing soil salinity, with the proper designation of engineering parameters being crucial. This study applied 12 treatments (T1–T12) consisting of four different spacings of subsurface drainage pipes (6 m, 11 m, 15 m, and no subsurface drainage pipes) and three observation wells at varying distances from the drainage outlet (5 m, 25 m, and 45 m). Results showed that all three subsurface pipe spacing treatments significantly reduced soil salinity compared to natural drainage, with a smaller subsurface pipe spacing treatment leading to better salt-reducing effects. The farther the distance from the measuring point to the drain, the higher the salinity. As the burial depth of the outlet decreased and spacing between the subsurface drainage pipes decreased, the salinization rate of the 0–60 cm soil layer was higher, while the salt accumulation in the 60–80 cm soil layer was more severe. Therefore, a subsurface drainage pipe spacing of 6 m and an outlet burial depth of 40 cm are recommended as more suitable choices to effectively control salt concentration in the soil. The research aimed to provide scientific reference data and technical support for the optimized design of subsurface drainage engineering parameters while promoting efficient desalination of saline-alkali areas worldwide.

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.

The traditional advancing front technique algorithm encounters many problems due to the complex geometric characteristics of the front edge shape. These problems include poor quality, a slow algorithm, low robustness, and the inability of the mesh unit to converge. To address these problems, an optimized adaptive triangular mesh dynamic generation algorithm called R-TIN is proposed and applied to 3D engineering geological modeling in this study. Firstly, all the shapes involved in advancing the front edge inward were classified into four types, and then the optimal triangular unit was constructed by using the candidate mesh point heuristic algorithm. Then, the robustness of this algorithm could be maintained by the graded concession of the included angle threshold in the adjacent front-line segments. Finally, based on 160 engineering geological boreholes in the study area, the 3D engineering geological model was constructed and the accuracy and visualization effect of the overall geological model have been greatly improved, which can better present the spatial distribution of strata and lithological characteristics. At the same time, this algorithm can be used in geoscience information services to support the regional or national exploration of resources and energy, sustainable development and utilization, environmental protection and the prevention of geological disasters.

China’s South–North Water Transfer Project has been questioned as it has resulted in significantly negative issues. Drawing on the notion of hydrosocial territories, this article examines the contested hydraulic configuration and counter-imaginaries from local water users’ perspectives and their specific adaptation strategies in the South–North Water Transfer Project. This article argues that local water users in a Chinese context can only adopt adaptation strategies that are determined by their socio-economic backgrounds. This has led to significant social and environmental injustice. Addressing these issues is crucial for tackling inequities in the South–North Water Transfer Project and achieving the ambitious development goals of the project.

Human-dominated landscapes have become a serious threat to amphibian populations worldwide. In such landscapes, concrete structures act as barriers to migration, fragmenting habitat and causing mortality. In China, concrete irrigation channels, which play an important role in agriculture, impede the movement of anuran amphibians. To promote the sustainable development of irrigated agriculture, we performed behavioral experiments to examine the ability of a common Chinese frog species (Pelophylax nigromaculatus) of four different body sizes to use corridors along a gradient of six different slopes to escape from irrigation channels. We found that body size was positively related with frogs’ ability to climb the ladders. Most frogs could not escape if the slope was ≥65 degrees, but all frogs could successfully navigate a ladder with a slope of 45 degrees. Based on our experimental results, we propose a simple improved design for amphibian ladders that would greatly improve the success of frogs in escaping from irrigation channels. This research is expected to provide scientific reference data and technical support for frog conservation in the study area, as well as the development of ecological restoration of irrigation districts throughout the world.

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.