Influence of Soil Salinization on Growth of Cotton in an Arid Area in Northwest of China

Abstract

This paper discusses the influence of soil salinization on cotton plant growth and the factors that cause salinization in irrigated farmland located along the northern part of the Tarim River, Xinjiang Uygur Autonomous Region, China. A field survey was conducted in a cotton field in Nuerbake Township, Xayar County. The physical properties of the soil, fluctuations in groundwater level, the growth of cotton plants and electrical conductivity (EC) of the soil saturation extract were investigated. The quality of irrigation water and groundwater was also measured at the study area. The groundwater level was low in the summer and high in early spring; this high level was due to thawing of the soil and irrigation for planting. However, use of border irrigation temporarily raised the groundwater level. Even within the same field, the EC of the soil saturation extract differed depending on locations and soil depths. An EC of the surface soil exceeding 8.0 dSm⁻¹ retarded cotton growth. We found that irrigation water quality did not affect the growth remarkably because the EC of the irrigation water was lower than 4.0-6.0 dS/m. On the other hand, the existence of a less permeable subsurface soil damaged cotton growth. The difference in hydraulic properties of the subsurface soil is influenced by the amount of clay that affects water and saline movement toward the surface.