Soil Salinity Changes Under Cropping with Lycium barbarum L. and Irrigation with Saline-Sodic Water

In order to utilize the wasted saline-sodic soils under shallow groundwater condition, a 3-year field study was carried in a field cropped with Lycium barbarum L. and irrigated by drip irrigation with saline groundwater under the water table depth of 30-40 cm in the northern Yinchuan Plain, China. Effects of cropping duration (one, two, and three years) on soil salinity, soil solution composition, and pH in three adjacent plots were investigated in 2008. Results showed that a high irrigation frequency maintained high soil water potential and subsequently facilitated infiltration and downward movement of water and salt in the crop root zone. Salt accumulated on the edges of the ridges, and soil saturated-paste electrical conductivity (ECe) was higher in the edge. Concentrations of Na(+), Ca(2+), Mg(2+), Cl(-), and SO(4)(2-) in the soil increased with the soil depth as did the ECe, while FICO(3)(-) and pH had a relative uniform distribution in soil profile. As planting year increased, the ECe and soil salts in the field had a decreasing tendency, while in the root zone they decreased immediately after irrigation and then remained relatively stable in the following growing seasons. HCO(3)(-) and pH had little change with the planting year. Results suggested that the application of drip irrigation with saline water could ameliorate saline-sodic soil and provide a relatively feasible soil environment for the growth of salt-tolerant plant Lycium barbarum L. under the saline-sodic soils with shallow groundwater.