Effects of acidified biochar amendment on water and salt movement in saline-alkali soil in drip-irrigated cotton field

Abstract

【Objective】 Acidified biochar has been used as a soil conditioner to improve properties of saline-alkali soils. This paper presents the results of an experimental study on the effect of acidified biochar amendment on water and salt movement in saline-alkali soil. 【Method】 Infiltration experiment was conducted using columns repacked with saline-alkali soil taken from a cotton field to the depth of 40 cm. The soil was amended with acidified biochar at a ratio from 1% to 5%. Soils without biochar amendment (CK1) and amended with 2% of non-acidified biochar (CK2) were taken as the control. The movement of wetting front, changes in soil pH, soil salt content, soil alkalinity and soil desalination in each treatment were measured and analyzed. 【Result】 The pH value of the soil amended with acidified biochar was significantly lower than that of the soil in CK1 and CK2, with pH value decreasing with the increase in acidified biochar application. With acidified biochar application increasing, soil alkalinity decreased first followed by an increase, with soil alkalinity being the least when acidified biochar application ratio was 2%. Soil desalination in the 0-50 cm of soil layer and salt accumulation in the 50-70 cm of soil layer both increased with the increase in application of unacidified biochar and acidified biochar. Overall, soil desalination was the best in soil amended by 2% of acidified biochar. 【Conclusion】 Amending soils by acidified biochar was more effective to improve the properties of saline-alkali soil than amending with non-acidified biochar. Among all treatments we compared, amending the soil by 2% of acidified biochar was most effective in improving soil properties.

Keywords

• wood vinegar
• biochar
• improved alkalized soil
• salinity vertical distribution