沂蒙山区不同土地利用方式下土壤理化性质及土壤质量的差异性

Differences in soil physical and chemical properties and soil quality under different land use types in the Yimeng mountainous region

基于沂蒙山区祊河流域不同土地利用方式下土壤理化性质分析,采用主成分分析法(principal component analysis,PCA)建立最小数据集(minimum data set,MDS),利用土壤质量指数(soil quality index,SQI)研究了该区不同土地利用方式下的土壤质量状况。结果表明:(1)不同土地利用方式下土壤物理性质变化明显。林地的土壤容重最小,砂粒含量最少,黏粒含量最多,土壤含水量较高,而园地正好相反;耕地土壤容重较大,砂粒和黏粒含量都较少,土壤含水量最高,而草地正好相反。(2)不同土地利用方式下土壤化学性质差异显著。土壤pH值由大到小依次为草地、林地、耕地、园地;林地和草地的土壤有机质、全氮、碱解氮和全钾含量均较高,而速效磷含量均较低;林地的土壤全磷含量最低而速效钾含量最高,草地正好相反;耕地和园地的土壤有机质、全氮、碱解氮和全钾含量均较低,而全磷、速效磷含量较高,耕地的速效钾含量较高而园地的最低;研究区域耕地和园地的土壤有机质、全氮和速效钾含量处于相对缺乏状态。(3)不同土地利用方式的土壤质量指数为SQI_(林地)(0.64)>SQI_(草地)(0.51)>SQI_(耕地)(0.35)>SQI_(园地)(0.23),土壤全氮含量是限制研究区域耕地、园地土壤质量的关键因素。(4)由土壤容重、砂粒含量、全氮含量构成的最小数据集(MDS)能够替代全量数据集(total data set,TDS)评价研究区域土壤质量。

The soil quality under different land use types in the Benghe River Basin of the Yimeng mountainous region were evaluated by analyzing the soil physical and chemical properties,using the soil quality index(SQI)and the minimum data set(MDS)established by using the principal component analysis(PCA)method.The results showed that:(1)The soil physical properties changed significantly under different land use types.The lowest soil bulk density,the least sand content,the most clay content and higher soil moisture content was found in forest land,while the opposite trend was found in garden land.Cultivated land had higher soil bulk density,less sand and clay content,and the highest soil moisture content,while the opposite was for grassland.(2)Soil chemical properties differed significantly under different land use types.Soil pH values were grassland>forest land>cultivated land>garden land.Soil organic matter,total nitrogen,alkaline nitrogen and total potassium were high,while available phosphorus was low in forest land and grassland.Total phosphorus was lowest and available potassium was highest in forest land,and the opposite was in grassland.Soil organic matter,total nitrogen,alkaline nitrogen and total potassium were low in cultivated land and garden land,while total phosphorus and available phosphorus were high,and available potassium was high in cultivated land and lowest in garden land.Soil organic matter,total nitrogen and available potassium were relatively deficient in cultivated land and garden land in the study area.(3)The soil quality index of different land use types was SQI_(forest land)(0.64)>SQI_(grassland)(0.51)>SQI_(cultivated land)(0.35)>SQI_(garden land)(0.23),and the total soil nitrogen content was the key factor limiting the soil quality of cultivated land and garden land in the study area.(4)The minimum data set(MDS)consisting of soil bulk density,sand content,and total nitrogen content could replace the total data set(TDS)for soil quality evaluation in the study area.