Against the backdrop of worsening global water scarcity, the development and utilization of unconventional water resources and the construction of diversified water supply systems have become key paths for countries to alleviate the contradiction between water supply and demand and promote sustainable agricultural development. Based on the statistical data of unconventional water resources over the past 20 years, this study first conducted a quantitative analysis of the current development status of unconventional water resource utilization in China. Then, it retrieved and analyzed the evolutionary trends of research in this field using the CNKI (China National Knowledge Infrastructure) and Web of Science databases; additionally, it systematically sorted out the utilization technologies, agricultural applications, and innovative practices of reclaimed water, rainwater, brackish water, and atmospheric water. The results showed that: The utilization volume of unconventional water resources in China has increased continuously over the past 20 years, reaching 25.16 billion m³ in 2024. In terms of spatial distribution, it presents the characteristics of "large total volume with concentrated distribution, more in the north and less in the south" the utilization of such resources in water-scarce northern regions, including the Haihe River Basin, Yellow River Basin, Beijing, and Tianjin, accounts for a prominent proportion. It is predicted that the available volume of agricultural unconventional water resources will reach 34.38 billion m³ by 2030, indicating significant development potential and broad application space for agricultural unconventional water resources; during 2000-2024, research in this field has shown a fluctuating growth trend, with themes focusing on reclaimed water irrigation, brackish water irrigation, and other directions. This research belongs to interdisciplinary and comprehensive studies, involving environmental science, agricultural engineering, agronomy, and other disciplines; research institutions are mainly universities in North China and Northwest China, and their layout responds to regional water scarcity demands. As the unconventional water resource with the largest utilization volume, reclaimed water needs to rely on the continuous innovation of membrane technology. It combines conventional treatment with advanced treatment, and is equipped with disinfection processes to achieve high reuse standards. Rainwater utilization focuses on the synergy between collection-storage and utilization, adopting composite and ecological rainwater harvesting to serve agriculture in arid regions, and matching with intelligent scheduling and new materials to improve management efficiency. Brackish water utilization centers on desalination, salt reduction, and crop stress mitigation, constructing a complete technical solution from pretreatment to advanced treatment. By integrating the strategies of mixed irrigation and alternate irrigation of brackish and fresh water, along with amendments and agronomic measures, it is suitable for the irrigation of salt-tolerant crops such as cotton and wolfberry. For atmospheric water harvesting, improving efficiency and reducing costs are the core; strengthening the combined surface water generation technology (an energy-efficient atmospheric water harvesting technology) can provide a new cost-effective water source path for agriculture in arid regions. In the future, through optimizing process combinations, reducing production costs, and strengthening regionally differentiated applications, the efficient development and scientific utilization of agricultural unconventional water resources will provide important support for sustainable agricultural development.

To An innovative irrigation system was proposed for facility cultivation tomatoes using weight feedback, in order to improve the accuracy of irrigation. Among them, the weighing feedback module was used to monitor the water requirements of tomato plants. Multi-source information acquisition and transmission were to collect and transmit the environmental information in the greenhouse. An irrigation decision module was to issue the irrigation commands for the switch of water pumps. A water-fertilizer actuation module was to configure and transport the nutrient into the crops. Initially, a satellite positioning module was employed to ascertain the latitude and longitude of the irrigation site, which was facilitated the automatic calculation of the sunrise, sunset, and solar noon times. Four phases of dynamic irrigation were autonomously segmented the day, according to the water absorption of coco coir strips and the diurnal transpiration patterns of tomato plants within the greenhouse. Furthermore, general mode of irrigating nutrient or desalination mode of irrigating pure water (or low-concentration nutrient solution) was formulated, according to the greenhouse temperature and humidity information, as well as the feedback on the root information of tomato plants that obtained from drainage conductivity. Experimental design was involved the radiation accumulation and timed irrigation as controls, in order to validate the applicability, in terms of cultivation, irrigation, and application benefits. The results indicate that the weight feedback system increased irrigation volume by about 1.8%, compared with the radiation accumulation. The fertilizer usage, drainage ratio, and drainage EC value were reduced by 7.3%, 7.9%, and 9.3%, respectively. The irrigation volume, fertilizer usage, drainage ratio, and drainage EC value decreased by approximately 11.3%, 20.0%, 17.9%, and 4.9%, respectively, compared with the timed irrigation. Cultivation results show that when the coconut coir strip-cultivated tomatoes were irrigated under this weight feedback irrigation system, there were no significant differences (P>0.05) in the stem thickness, relative chlorophyll content of leaves, sugar content, and single ear mass, compared with the radiation accumulation. Additionally, the plant height increased by 4.8%. There were no significant differences (P>0.05) in the plant height, stem thickness, relative chlorophyll content of leaves, sugar content, and single ear mass, compared with timed irrigation. It was expected that 15 solar greenhouses (1.22 hm²) were contributed to save 27.6 thousand yuan per month and 22.6 thousand yuan per hectares per month using the weight feedback system, compared with the radiation accumulation; The park can save 22.47 thousand yuan per month in application benefits, compared with the timed irrigation and 18.47 thousand yuan per hectares per month. As such, the previous cumbersome calculation of water demand was greatly simplified to achieve the precise detection of tomato water and precision irrigation for the Rockwool cultivation and the mixed substrate potted cultivation.