Abstract: In order to study the effects of organic fertilizer, wood chips, biochar and gypsum on base cations (K⁺, Ca²⁺, Na⁺, Mg²⁺)leaching, soil column simulation experiment was carried out. It was shown that addition of any above material could effectively increase the leaching amount of base cations, and improve soil quality. Under the experiment conditions, addition of 25 g organic fertilizer or gypsum, respectively, led to the highest leaching amount of K⁺, Ca²⁺, Na⁺, Mg²⁺ as compared to other doses. As for wood chips, the leaching amount of Ca²⁺, Na⁺, Mg²⁺ reached the highest level with addition of 12.5 g wood chips, while the leaching amount of K⁺ was the highest without wood chips. As for biochar, the leaching amount of Ca²⁺, Mg²⁺ reached the highest level with addition of 12.5 g biochar, while the leaching amount of K⁺, Na⁺ was the highest with addition of 25 g biochar. Comprehensively, the following solutions were effective for base cations leaching: (1) Irrigation. This method was simple and time-saving, but, it cost a lot of water. (2) Adding amendment. Based on the findings in the present study, addition of 25 g organic fertilizer, 12.5 g wood chips, 12.5 g gypsum exhibited the best leaching effect and the highest efficiency under the set conditions.

Key words: Zhoushan, saline-alkali soil, soil improvement, soil column experiment