岩溶区不同土地利用方式下土壤养分的剖面分布特征

为研究岩溶区不同土地利用方式下土壤养分的剖面分布特征，对5 种土地利用方式（橘园地、草地、菜地、灌丛地、耕地）下土壤养分含量及剖面分布特征进行对比分析。结果表明：（1）土地利用方式对土壤有机质、速效磷、速效钾有显著影响，而对全氮、水解氮、全磷、全钾没有显著影响。土壤有机质从高到低依次为：草地>菜地>橘园地>灌丛地>耕地；土壤速效磷从高到低依次为：灌丛地>草地>耕地>橘园地>菜地；土壤速效钾从高到低依次为：橘园地>草地>菜地>耕地>灌丛地：（2）从不同土地利用方式土壤剖面特征来看，有机质、水解氮、全磷、全钾、速效钾表聚特征明显；（3）土壤中大部分养分与土壤颗粒有一定的相关性，其中砂粒与土壤养分相关性最好。

Profile distribution characteristics of soil nutrients under different land use types in the karst areas

In order to investigate the profile distribution characteristics of soil nutrients under different land use types in the karst areas, the impact of different land use types including orchard land, grassland, vegetable land, shrub land and farmland on soil nutrient distribution was analyzed. The results showed: (1) Soil organic matter(OM), available phosphorus (P), available kalium(K) were significantly affected by land use types, while total nitrogen(TN), available nitrogen(N), total phosphorus(TP), total kalium (TK) were not significantly affected by land use types. The order of content of OM in different land use types was grassland>vegetable land>orchard land>shrub land>farmland, the order of content of P in different land use types was shrub land>grassland>farmland>orchard land>vegetable land, the order of content of K in different land use types was orchard land>grassland>vegetable land>farmland>shrub land; (2)OM, N, TP, TK, K content had the character of surface accumnulation in some extent; (3)There existed significant relationship between most nutrients in soil and various oil granule contents and soil sand, had the best relationship with soil nutrients.