A study of typical plant growth changes in response to drainage water and salt in ditch wetland in arid area

Agricultural drainage significantly affected the changes of soil moisture and salinity in ditch wetlands. These changes can profoundly impact the spatial distribution and evolution of ditch wetland vegetation, thereby affecting the ecological environmental effects of these wetlands. Consequently, it is imperative to investigate the response of typical plant growth to drainage and soil salt in ditch wetlands in arid regions. Based on the classical metapopulation conceptual framework model (Levins model), this study established a new model of plant growth change in ditch wetlands, incorporating the key variables (water level and soil salinity) of arid area ditch wetlands. The application of the Gaussian model facilitates the resolution of species growth rates and mortality rates within this model. The study focused on the main drainage ditch (ditch M) and the drainage bucket ditch (ditch N) in the Lubotan saline-alkali land in Fuping, Shaanxi Province. The results revealed the following key findings: 1) the model effectively simulates the response of plant growth changes to water level and soil salinity in ditch wetlands in arid regions, particularly plants in the reed area and transition area disturbed by single factors such as water level and soil salinity; 2) the germination period of Phragmites australis in the reed area thrives in a shallow moisture environment, and adjusting the water level of the drainage ditch can maintain optimal growth conditions for Phragmites australis; 3) during the germination period of Suaeda salsa in the transition area, soil salinity should not be excessively high, though a moderate increase in soil salinity can promote the germination and growth of Suaeda salsa; and 4) Suaeda salsa in the symbiotic area has a higher adaptability to the soil salinity, with change in biomass consistent with plants in the transition area. The model provides an explanation and prediction for the growth changes of plant communities in ditch wetlands under drainage conditions. By integrating this model with the impact of farmland drainage on water level and soil salinity in drainage ditches, effective drainage management measures can be formulated, offering scientific support for the construction of ecological irrigation areas.