Irrigated Agriculture and Salinization

Abstract

The Loess Plateau has complex topography with deep, thick loess, and is poor in water resources. The soil is loose and rich in carbonates, but because these dissolve readily when moistened, the soil is susceptible to subsidence and erosion damage when wet. These natural characteristics have hindered irrigation development on the plateau. Irrigation methods on the plateau can be classified into three categories: (1) gravity irrigation on flat tablelands in the southern region, (2) gravity irrigation on steep topography, and (3) pump irrigation on relatively flat, high plains. Among these three, (1) and a part of (2) have potential salinization hazards, with no such potential for category (3) and most of category (2). We analyzed the relationship between topographic characteristics and potential salinity hazards of irrigated farmlands in the Luohui Irrigation District, a typical large-scale irrigation system located on the southeast Loess Plateau. Based on onsite observation, we summarize current and potential problems of irrigated farmland within a semiarid area. Salinization of irrigated farmland is greatly influenced by water management. The construction, operation, and management of a well-conceived and elaborate water management system is a requirement for sustainable agriculture.