**1. Introduction**

About 22–32% of the world's terrestrial plants have their roots near or within the groundwater [1, 2]. As a result, groundwater significantly impacts the transpiration of aboveground ecosystems and net primary productivity [3–5]. On a global scale, groundwater contributes about 23% to vegetation water consumption on average [6]. In areas with shallow groundwater, it contributes up to 84% of the total transpiration of vegetation. In arid areas [7], almost all water consumption of the plant comes from groundwater [8]. However, groundwater contributes little or even negatively to transpiration in irrigated agriculture or coastal areas with shallow water table depth, due to its high salinity [9]. At present, with the expansion of the agricultural area, the supply of freshwater resources is becoming more and more insufficient; agricultural production began to use underground saltwater, or which combined with saline water irrigation, along with the development of water-saving irrigation technology and water conservancy engineering measures suitable for the

region. Therefore, further research is strongly needed to promote the efficient use of agricultural moisture in areas with shallow groundwater, to figure out the crop growth process under the influences of irrigation and shallow water replenishment, and the salt balance characteristics under different management measures. Consequently, it is beneficial to find out how to use the abundant shallow underground saltwater in the coastal zone as a resource instead of limitations, realize the recycling of groundwater resources, and solve the source problem of lacking freshwater in terms of water-salt regulation.
