EFFECT OF DESULFURIZATION GYPSUM ON SALINE-ALKALI SOIL IN NINGXIA UNDER RIDGE CULTIVATION AND DRIP IRRIGATION

Addressing the actual issues of severe soil salinity and exchangeable sodium percentage (ESP), and water shortage in the Yellow River irrigation area of Ningxia. With the goal of controlling soil salinity and reducing ESP, ridge cultivation and drip irrigation technology were adopted. Through field positioning experiments, three desulfurization gypsum (DG) application rates of 12 t/hm2 2 (T1), 15 t/hm2 2 (T2), and 18 t/hm2 2 (T3) were set up in the ridge planting area, with a control treatment without desulfurization gypsum (CK) to explore the effect of different desulfurization gypsum application rates on saline-alkali soil in the Yellow River irrigation area of Ningxia under high ridge drip irrigation mode. The results showed that: (1) The application of desulfurization gypsum was beneficial in reducing soil ESP and pH, with the T3 treatment showing the most significant reduction effect; (2) Drip irrigation was conducive to creating a suitable water- salt environment for the ridge planting area. The soil salinity in the 0-20 cm layer of the T1 treatment was 22.5% and 32.2% lower than those of the T2 and T3 treatments, respectively, with soil salinity accumulating in the ridge furrows; (3) Under ridge cultivation and drip irrigation mode, the application of desulfurization gypsum promoted the growth of sweet sorghum, but the higher the application rate of desulfurization gypsum, the better the effect was not necessarily observed. The growth indicators of sweet sorghum in the T2 treatment were the highest. Under the ridge cultivation and drip irrigation mode, the application of 15 t/hm2 2 desulfurization gypsum had the best effect on controlling soil salinity and reducing ESP. The research results can provide theoretical basis and technical support for the improvement and utilization of moderately to severely saline-alkali land in the arid areas of Northwest China.