An Innovated Drip Irrigation Technique for Improving Water Use Efficiency and Increasing Salt Leaching from Cotton Fields

【Objective】 Soil salinization is one of many factors faced by cotton production in Xinjiang. Improving irrigation is one way to mitigate their detrimental impact. In this paper, we present an innovative drip irrigation system to ameliorate the effect of soil salinization and conserve water resources. 【Method】 The proposed method was based on that under drip irrigation, salt accumulates in the periphery of the wetted zone around the drip emitters. We reconfigured the conventional drip irrigation system into a system consisting of three-capillary tubes with staggered emitters. Parameters, including spacing between the capillary tubes, drip layout patterns, irrigation amount, and salt leaching were determined experimentally to elucidate its efficacy on salt migration in the wetted zones. 【Result】 Keeping soil properties and water quality consistent, we implemented the staggered delivery of water through the system in a cotton field. After six rounds of irrigation, soil samples were collected from the wetted zone to assess salt content in it. The vertical salt content distribution at a location 40 cm from the wetted zone decreased from 105.21 g/kg to 49.015 g/kg. This means that the proposed system effectively increased the desalination of the root zone and resulted in a reduction in annual saltwater usage by three times per year, compared with conventional drip irrigation. 【Conclusion】 The expansion of the desalination zone in the root zone is contingent on factors such as soil bulk density, irrigation method, frequency, drip patterns, soil salinity, irrigation water salinity, and irrigation cycles. As irrigation rounds increase, the desalination range grows. The method hence offers a promising strategy for managing saline-alkali lands while in the meantime optimizing water use efficiency.