【摘要】 耕层土壤质量直接影响坡耕地土地生产力,为准确评价紫色土坡耕地耕层土壤质量特征,本文以云南楚雄、广西桂林、江西兴国和广东南雄4个区域紫色土坡耕地耕层(0～20 cm)土壤为研究对象,利用主成分分析、相关分析相结合方法对12个土壤属性指标筛选,建立坡耕地耕层土壤质量最小数据集并对耕层土壤质量评价。结果表明:1)紫色土坡耕地耕层土壤养分较为贫瘠,土壤有机质(14. 89 g/kg)和全氮(0. 85 g/kg)为四级水平,有效磷(28. 84 mg/kg)为二级水平,p H值显弱酸性;土壤密度为0. 93～1. 62 g/cm~3,耕层厚度在15～30 cm变化,总体看土壤化学指标变异性大于物理指标变异性,2)紫色土坡耕地耕层土壤质量评价最小数据集由土壤密度、有效磷、有机质、饱和导水率、贯入阻力、砂粒、耕层厚度7个指标构成,可反映紫色土耕层土壤质量有效信息,评价结果具有较好准确性,3)紫色土坡耕地耕层土壤质量表现为云南楚雄>广西桂林>江西兴国>广东南雄。研究结果可为紫色土坡耕地耕层土壤改良和合理耕层构建提供科学参数。更多还原

【Abstract】 [Background]The soil quality of a plowing layer directly affects the productivity of sloping farmland,in order to accurately evaluate the soil quality characteristics of a plowing layer for purple sloping farmland,objectively evaluate the soil quality in the plowing layer of purple soil sloping farmland is an important basis for preventing the soil erosion and degradation of purple soil sloping farmland and ensuring the high efficiency and stability of the soil productivity in plowing layer. [Methods] The plowing-layer( 0-20 cm) soil of purple sloping farmland of Chuxiong-Yunnan, Guilin-Guangxi,Xingguo-Jiangxi and Nanxiong-Guangdong were collected as the research objects. The minimum data set( MDS) was established and the cultivated-layer soil quality was evaluated by the combination of principal component analysis( PCA) and correlation analysis based on the 12 soil property indexes which were selected. [Results] 1) Soil quality of cultivated-layer for sloping farmland varied significantly among different purple soil sites. Soil nutrients of cultivated-layer were poor relatively,soil organic matter( 14. 89 g/kg) and total nitrogen( 0. 85 g/kg) were on the fourth level,and available phosphorus( 28. 84 mg/kg) on the secondary level of the classification criterion of soil nutrient,p H value was faintly acidity. The ranges of soil bulk density was 0. 93-1. 62 g/cm~3,and the cultivated-layer thickness varied of 15-30 cm,The variability of soil bulk density,silt content,cultivated-layer thickness,pH value variability were small. Sand content,penetration resistance,shear strength and total nitrogen with general variability,and the clay content,saturated water conductivity,organic matter and available P were in large variability. In general the variability of soil chemical indexes were greater than that of physical indexes. 2) The MDS on soil quality evaluation included the seven indexes of soil bulk density,available phosphorus,organic matter,saturated hydraulic conductivity,penetrate resistance,sand content and cultivated-layer thickness,which reflected the effective information of soil quality of cultivated-layer with accuracy evaluation result for soil and water conservation fertilizer conservation and yield-increasing potential. 3) The soil quality of cultivated-layer for purple sloping farmland was ordered as ChuxiongYunnan > Guilin-Guangxi > Xingguo-Jiangxi > Nanxiong-Guangdong. The obstacles of cultivated-layer with low penetrate resistance and soil bulk density in Chuxiong-Yunnan,lower organic matter and cultivated-layer thinning were the obstacles of cultivated-layer for Guilin-Guangxi and NanxiongGuangdong seperately,Xingguo-Jiangxi with the obstacle of slightly higher sand content and lower saturated water conductivity. [Conclusions]The results may provide some useful scientific supports not only for the soil quality recovery of the cultivated-layer but for the sustainable utilization of crop growth and the control of soil and water loss of purple soil sloping farmland,which are also conducive to soil improvement,reasonable cultivated layer construction and sustainable utilization of the sloping farmland recourses in purple hilly area.更多还原