Salt removal technology by shallow subsurface drainage in combination with a cut-drain

Abstract

In Uzbekistan, secondary salinization of irrigated lands is caused by rising groundwater level due to excessive irrigation and drainage system malfunction. Countermeasures such as drainage system maintenance, drainage facility construction, and leaching have been adopted to control salinity. However, there are still fields where salinity levels remain high because of incomplete dredging operations, reduced deep subsurface drainage system discharge capacity, or ineffective approaches to vertical drainage operations. To achieve stable production and crop diversification, prompt salt removal is necessary. Thus, we proposed a shallow subsurface drainage technology to ensure effective salt removal from the surface soil layer. The technology was investigated in combination with a new drain drilling technique (cut-drain) developed in Japan. It was experimentally introduced in farmers’ fields in the Syrdarya Province. A leaching test performed in the study field revealed that highly saline water was observed at the outlet of the drainage pipe. The results of our study showed an approximately 20% increase in cotton yield, along with a decreasing salinity trend in the surface soil layer. Our study demonstrated that this technology can be employed as an effective measure for controlling salinity in a field.