中文摘要：

在水稻田、玉米地、撂荒地和人工林地4种土地利用方式下，对潮棕壤0-150cm土层中土壤交换性钙（Ca）和交换性镁（Mg）的剖面分布及Ca／Mg的变化进行了比较研究．结果表明：不同利用方式下土壤交换性Ca含量及储量差异不明显；林地各土层的土壤交换性Mg含量均显著高于水稻田（P〈0．05）；交换性Mg储量大小依次为林地、玉米地、撂荒地和水稻田（P〈0．05）．不同利用方式交换性Ca／Mg随土层深度的增加而降低，40cm以下土层水稻田Ca／Mg显著高于其他3种利用方式（P〈0．05）．土壤生态系统中Mg的优先固持、土壤管理以及植物自身的特性如生物量的循环速率、生物量在地上部分和地下部分的分配、根系的分布等，对土壤剖面中交换性Ca和交换性Mg的构成以及土壤交换性Ca库和Mg库的重建等起到重要作用．

英文摘要：

A comparative study was made on the profile distribution of exchangeable Ca and Mg and Ca/Mg ratio at the depth of 0-150 cm in an aquic brown soil under four land use patterns, i. e. , paddy field, maize field, fallow field, and woodland. The results showed that less difference was observed in the soil exchangeable Ca content and storage among different land use patterns. For soil exchangeable Mg, it was significantly higher in woodland than in paddy field, and its storage was in the sequence of woodland 〉 maize field 〉 fallow field 〉 paddy field （ P 〈 0. 05 ）. The exchangeable Ca/Mg ratio tended to decrease with soil depth, and was significantly lower in paddy field than in other three land use patterns in the soil layers below 40 cm （P 〈 0. 05 ）. The preferential retention of Mg in soil ecosystem, soil management practices, and plant characteristics, e.g. , biomass cycling rate, biomass above- and below-ground allocation, root distribution, and maximum rooting depth） might play important roles in shaping soil exchangeable Ca and Mg profiles and in recon structing soil exchangeable Ca and Mg pools.