Agricultural utilization and vegetation establishment on saline-sodic soils using a water-salt regulation method for scheduled drip irrigation

Reclamation of saline-sodic soils for agricultural and vegetation ecological establishment is an important way to solve food and environmental problems, especially in developing countries. A water-salt regulation method using scheduled drip irrigation to control the soil matric potential (SMP) at a depth of 0.2m immediately under drip emitters was proposed and the application effect of the method applied in field experiments was evaluated for reclamation of saline-sodic wasteland at five sites with different climates, land-use objectives, and planting patterns. A low-salinity environment was created in the whole soil profile, especially in the root zone, and the salt leaching process was divided into three stages: rapid desalination, slow desalination, and salt stabilization. The soil environment was improved with reclamation time, resulting in improved land productivity, crop yields at levels close to those in local farmland after 2-3 years, and good landscape vegetation ecosystems were created by establishment of artificial vegetation and natural germination of seeds in the soil seed bank. Soil alkalization should receive some attention during the salt leaching process because it may affect the growth of acid-loving plants. In addition, the low survival rates for salt-sensitive/non-salt tolerant landscape plants in the early reclamation period led to the creating a non-saline soil environment by adding non-saline soils into planting holes. Overall, the water-salt regulation method to control SMP immediately under scheduled drip irrigation emitters is suited for saline-sodic soils restoration, and some suggestions were proposed for its better application according to the field experiments.