关键词: 土壤质地, 树龄, 交换性钙镁

Abstract: In order to understand the change rule of exchangeable Ca and Mg content under different soil texture and tree-age condition, this paper choose sandy and loam 2 kinds of walnut tree orchard, one in primary fruit period and the other in full fruit period, and tested the exchangeable Ca and Mg contents in soil. The results showed that there were remarkable differences in contents of exchangeable Ca and Mg in different soil texture. Relatively speaking, the loam had strong adsorption and immobilization capacity of Ca2+, and also high Ca2+ content. There were significant differences in contents of exchangeable Ca and Mg between loam and snay soil（P＜0.05）. Under loam condition, there were also big differences in soil exchangeable Ca and Mg contents between 2 different tree-ages. Soil types had certain effect on the change of soil exchangeable Ca/Mg. Exchangeable Ca and Mg showed significant negative correlation between loam and sandy soil. While under the same soil condition, Ca and Mg showed significant positive correlation. The ratio of exchangeable Ca/Mg was negatively correlated with the content of exchangeable Mg.

Key words: soil texture, tree-ages, exchangeable calcium and magnesium