Salinity variability of soda meadow alkaline soil in different depths of subsurface pipe

Abstract

The study investigates the impact of subsurface pipes at different depths on physicochemical properties of soda meadow alkaline soil. Field experiments were carried out in 5 treatments: CK (no treatment), CK1 (treatment with comprehensive supplementary measures: subsoiling to 0.6 m and applying farm manure in the amount of 34 m3/hm2, then mulching with sandy soil of 500 m3/hm2), and 3 treatments of comprehensive supplementary measures combined with subsurface pipes at different depths (H1 = 0.8 m, H2 = 1.0 m, and H3 = 1.2 m). The results suggest that soil permeability, organic matter content, available nitrogen, available potassium, and cation exchange capacity (CEC) in all treatments were significantly improved except for CK. The application of comprehensive supplementary measures improved soil pH, electrical conductivity (EC), total salt content (TS), total alkalinity (TA), and sodium adoption rate (SAR). Compared to CK1, treatments of H1, H2, and H3 decreased TS, TA, and exchangeable sodium percentage (ESP). Moreover, the treatment with shallow buried pipe (H1 = 0.8m) decreased more in soil pH, EC, and SAR, and promoted more in rice yield than the other treatments. These results suggest that shallow buried subsurface pipe (0.8 m in depth and 5 m in space) has the best amelioration in soda saline-alkali soil region, when the same rice-planting and comprehensive supplementary measures were adopted.