不同土地利用方式及开垦时间对岩溶山区土壤养分空间分布的影响

Effects of Different Land Uses and Cultivation Periods on Spatial Distribution of Soil Nutrients in Karst Mountainous Region

采集贵州普定典型岩溶山区7种土地利用方式和3个不同开垦时间(27 a、39 a、48 a)的0～10 cm、10～20 cm、20～40 cm土壤样品,进行室内理化分析.结果显示,林地土壤有机质、全氮、碱解氮累积量较多,玉米黄豆地含量最少.林地土壤0～10 cm层有机质、全氮、碱解氮分别比玉米黄豆地高271.0%、317.7%、246.1%.林地和撂荒地对土壤养分循环较为有利.林地开垦为农业用地后,土壤有机质、全氮、碱解氮含量明显下降,全磷、有效磷、全钾含量没有明显变化,有效钾含量增多.开垦39 a的0～10 cm层土壤有机质、全氮、全磷、有效磷、有效钾含量高于开垦27 a和48 a土壤的含量,碱解氮低于开垦27 a和48 a土壤的含量;开垦27 a的土壤全钾含量高于开垦39 a和48 a土壤的含量.开垦时间长或短对土壤养分含量的影响未表现特殊规律性,可能受到其他因素的影响.

Puding County in Guizhou,China is a typical karst mountainous region,where the 0～10 cm,10～20 cm,20～40 cm soil samples were collected from an area with 7 types of land uses and 3 cultivation periods（27 a,39 a,48 a）.The contents of soil nutrients including organic matter（OM）,total nitrogen（TN）,total phosphorus（TP）,total potassium（TK）,available nitrogen（AN）,available phosphorus（AP） and available potassium（AK） were determined and analyzed.The result showed that the contents of OM,TN and AN in forest land were higher than those of other land uses.OM,TN and AN in maize-soybean fields were lowest.OM,TN and AN in 0～10 cm soil of forest land were 271.0%,317.7% and 246.1% higher than those in maize-soybean fields,respectively.Forest land and uncultivated land had advantage in soil nutrient cycling.OM,TN and AN decreased with the process of forest land becoming cultivated land,TP,AP and TK were not found with this trend,but AK increased in this process.However,in this study different cultivation periods（27 a,39 a,48 a） had no significant effect on soil nutrients,which indicate that other influencing factors might exist.