| Biochar, as a soil conditioner, is little known on its impacts on salt leaching of saline soil. In this experiment, 10% rates of mushroom medium biochar was added into different layers (0～20 cm, 0～35 cm, 0～70 cm) in a sulfate saline soil column collected from Hetao area in Inner Mongolia. Following washing with deionized water, the eluent was collected and measured for electrical conductivity (EC) and main ion contents. The study aims to investigate the effect of adding biochar into the different soil layers on leachings of salts and ions. The results showed that the eluent from biochar-amended columns appeared much earlier, by 34～37 days. The time for EC reduction to lower than 5 mS·cm-1 was shortened by 94～101 days. Adding biochar into the soil layer of 0～35 cm achieved earlier eluent and better leaching effect compared with other two treatments in which biochar was added into 0～20 cm and 0～70 cm soil layer. Biochar addition had different impacts on ion leaching. It promoted leaching of Na+, K+ and Mg2+, but inhibited Ca2+ leaching out of soil. Biochar addition promoted the leaching of both Cl- and SO42- at early stage and the leaching of HCO3- and CO32- at late stage. The obtained result may imply that the biochar amended into saline soil as a soil conditioners could shorten salt leaching time and increase salt leaching efficiency as well. |