Treatment of the saline-alkali soil with acidic corn stalk biochar and its effect on the sorghum yield in western Songnen Plain

Due to biochar could improve the physical and chemical properties of soil and promote crop growth, it is widely used in soil remediation, especially in saline soil. However, it is rarely studied of the application of acidic biochar in saline-alkali land. A field experiment with acidic corn stalk biochar (ACSBC) as a soil amendment was carried out in the western Songnen Plain of China. ACSBC (0, 0.15, 0.3, 0.45, 0.6, 0.75, 1, 6 and 15 t ha−1) was added to the topsoil to evaluate the combined effects on soil and sorghum yield. During the seeding and harvest period, the content of soil water, nutrient elements, cation exchange capacity (CEC), organic matter (OM), soluble cations (K+, Ca2+, Mg2+) increased, Na+ content showed opposite trend. However, soil pH decreased averagely with 0.3 and 1.0 during the seeding and harvest period respectively, salinity decreased with 19.37% and 18.14%, exchange sodium percentage (ESP) decreased with 37.08% and 37.04%. The sorghum yield increased 32.98% averagely, significantly by 51.37% and 47.33% with the 0.6 and 1 t ha−1 of ACSBC treatments respectively. These experimental results show that proper application of ACSBC in saline-alkali soil can effectively improve soil properties and increase sorghum yield.