Whether canal command irrigation through pressurized irrigation system deteriorates soil properties in hot arid ecosystem of India?

Abstract

Introduction of canal irrigation in arid zones may result into secondary salinization. However, adoption of judicious use of irrigation water through pressurized irrigation network may avoid the problem of soil salinity. In this study, soil properties in canal command area of Narmada Canal Project (NCP) in Rajasthan India having 2.46 lakh ha command area with pressurized irrigation network were assessed through field sampling followed by laboratory analysis. Soil physicochemical properties [pH, soil organic carbon content (SOC) and electrical conductivity (EC)] and soil chemical properties (contents of N, P, K, Fe, Cu, Zn and Mn) were determined for 200 soil samples collected from topsoil (0–15 cm) covering both irrigated and rainfed land use and three NCP command zones (lift area, flow area and ‘ned’ area). Principal component analysis (PCA) reduced the dimension of data to four major principal components (PCs). Few of these PCs were found to vary significantly across land use categories and NCP command zones. K-means clustering of observations showed that it can be segregated to either two or three clusters, however clustering efficiency was not good. Most of the observations lied in a single cluster indicating that all soil properties are almost similar to each other. Most of the extreme observations belonged to irrigated land use indicating that irrigation in few pocketed areas have been leading to deterioration of soil properties but can be managed through proper canal lining and excluding saline groundwater as a source of irrigation.