耕地土壤pH值和有机质含量空间分布特征及影响因素——以长沙县为例

Spatial Distribution Characteristics of pH Value and Organic Matter Content in Farmland Soil and Influencing Factors in Changsha County

为了解长沙县耕地土壤有机质丰缺状况和空间分布特征,采集了长沙县2 118份耕层(0~20 cm)土壤样本,测定土壤pH值、土壤有机质含量,分析了不同母岩母质、土壤质地、土地利用方式对土壤pH值和有机质含量的影响。结果表明:长沙县耕地土壤主要以微酸性为主,其中部和北部耕地土壤酸性更强;土壤有机质含量较高,呈北高南低的分布趋势;不同母岩母质中,除砂岩风化物发育的土壤呈酸性,其他类型的母岩母质形成的土壤均呈弱酸性,土壤有机质含量平均值范围为27.2~38.3 g/kg;不同土壤质地中,轻壤的pH均值最高,为6.3,砂壤的pH均值最低,为5.5,有机质含量排序为轻壤>砂壤>中壤>黏土>重壤;不同土地利用方式中,水田的pH值平均为5.92,有机质含量平均为34.2 g/kg,旱地的pH平均值是5.89,有机质含量平均为30.5 g/kg。

In order to understand the abundance and spatial distribution characteristics of organic matter in farmland soil in Changsha County,2118 soil samples from farmland(0-20 cm)in Changsha County were collected.The pH value and organic matter content in soil were measured,and the effects of different parent rock materials,soil texture,and land use methods on pH value and organic matter content in soil were analyzed.The results show that the farmland soil in Changsha County is mainly slightly acidic,with stronger acidity observed in the central and northern parts of the farmland soil.The organic matter content in soil is relatively high,showing a distribution trend of high in the north and low in the south.Among different parent rock materials,only the soil developed by sandstone weathering is acidic,and the soil formed by other types of parent rock materials is slightly acidic.The average organic matter content in soil ranges from 27.2 to 38.3 g/kg.Among different soil textures,the mean pH value of light soil is the highest(6.3),and that of sand soil is the lowest(5.5).The organic matter content in descending order is light soil>sandy soil>medium soil>clay>heavy soil.Among different land use methods,the average pH value and organic matter content of paddy fields are 5.92 and 34.2 g/kg,respectively.The average pH value and organic matter content of dry land are 5.89 and 30.5 g/kg,respectively.