Effect of the biochar interlayer on saline wasteland desalination and the development of Suaeda salsa roots
Qiang Xu, Han Han, Yibin Xu, Hanji Xia, Mingsi Li, Ping Gong, Chunxia Wang, Yufang Li, Pengfei Li, Hongguang Liu
Abstract
up interlayers to prevent upward salt movement may effectively manage salt accumulation in the root zone of saline wasteland with high groundwater levels and evaporation. To assess the impact of a biochar interlayer combined with Suaeda salsa on saline wasteland improvement, field experiments involving the burial of biochar interlayers within a 40 cm soil layer were conducted over two years. Four different amounts of biochar were tested: 0 Mg ha –1 (CK), 15 Mg ha –1 (M1), 45 Mg ha –1 (M2), and 75 Mg ha –1 (M3). The results indicated that the biochar interlayer treatment increased soil spatial heterogeneity and altered the spatial distributions of soil water, salt, and fertilizer. In the 0–50 cm soil layer, this treatment notably increased the soil moisture content by 5.33 %–20.69 %, and the soil water content increased with increasing biochar amount. The soil salinity in the 0–40 cm soil layer decreased by 13.85 %–40.74 %, and with increasing biochar content, it first decreased but then increased. The biochar interlayer treatment also increased the soil nitrate nitrogen concentration by 3.68 %–23.87 % and reduced the deep leaching loss of nitrogen. There was a positive correlation between root morphology and the soil nitrogen content, increases in root morphology parameters of 3.26 %–27.52 %, respectively. The root system absorbed more water, salt, and nutrients from the biochar layer, increasing the total biomass by 22.12 %–65.92 %, and the total salt absorption capacity increased by 30.62 %–85.03 %. Hence, biochar interlayer (45 t ha −1 ) represents an efficient approach for the ecological development of saline wasteland, with promising application prospects in extremely arid regions. • The synergistic desalination rate of biochar interlayer and S. salsa is over 50 %. • The soil salt accumulates and stabilizes at the biochar interlayer. • Biochar interlayer improves nitrogen availability and reduces deep leaching loss. • There was a positive correlation between root system morphology and soil nitrogen distribution.