The effect of winter flood irrigation with saline water on groundwater in a typical irrigation area

Abstract

Flood irrigation in the winter has been widely applied in northwest China for several years, but little attention has been paid to the flood irrigation program to date. In order to seek a reasonable irrigation quota, a flood irrigation experiment using two common quotas (1,800 and 1,200 m3 ha−1) was conducted in an area irrigated by saline water in the Nanjiang basin with shallow groundwater. Soil electrical conductivity in six treatments irrigated by saline water, with various salinity backgrounds, was investigated using Hydra and DDS-307 before and after flood irrigation. The results indicate that the quota of 12,00 m3 ha−1 was small enough to prevent soil salt from leaching out of the root zone. Although the quota of 1,800 m3 ha−1 may guarantee regular plant growth in the following year, it resulted in at least 267.2 g m−2 of salt entering the shallow groundwater. Therefore, flood irrigation had an important and profound effect on plants, soil environment, and shallow groundwater. The quota of flood irrigation in winter should be determined cautiously according to the hydraulic characteristics and salt background of the soil.

Accumulation of Na+ in cotton field under mulched drip irrigation of brackish water in arid areas

“…When the concentration of Na is lower than 500 mg/kg, the growth of cotton seedling is signi cantly promoted (Li, 2006). Because plants absorb and take away relatively little sodium, approximately 60-80% of the sodium applied to the soil remains in the soil (He et al, 2015;Wang,2018). The Cl−, Ca2+, and Na + contents in cotton plants increase during the growing period, and more salt ions are transported from the roots (Min, 2014) to the aboveground parts and accumulate in the stems and leaves (Mostafazadeh-Fard, 2012), while less salt ions accumulate in the buds and bolls (Wang et al, 2007).…”