向家坝工程扰动区不同类型边坡土壤不同形态磷的分布

Fractions and Distribution of Phosphorus at Various Types of Slopes in Disturbed Area of Xiangjiaba Hydropower Construction

对向家坝工程扰动区不同类型边坡土壤磷元素形态分布特征进行了研究.结果表明,向家坝工程扰动区不同类型边坡土壤中全磷、有机磷和速效磷含量较高,无机磷含量较低.7种不同类型边坡土壤中,总无机磷含量为154.4～993.0 mg/kg,占全磷的22.6％～47.1％.随着全磷含量的逐渐增加,各形态无机磷、有机磷、水溶性磷和Al-P占全磷的比例逐渐增加,而O-P、Ca-P占全磷的比例随着全磷的增加而减少.各无机磷形态分布情况为,水溶性磷和Al-P以植被混凝土基材最高;O-P的含量以天然次生林最高;Ca-P的含量以客土喷播最高.对各形态无机磷与速效磷相关性分析表明,只有水溶性磷和Al-P与速效磷呈极显著正相关.各形态无机磷之间,只有水溶性磷与Al-P之间存在极显著相关性,其余各形态无机磷之间相关性均不显著.7种类型边坡土壤的土壤磷素活化系数（PAC）均大于2.0％,说明土壤中的全磷易转化为速效磷,以供当地植被生长的需要.

Various types of slopes in disturbed area of Xiangjiaba hydropower construction selected were to study the distribu-tion of phosphorus（P）.The results showed that the contents of total P,organic P and available P were higher,but inorganicP was lower.The content of total inorganic P in the seven different types of slopes above was between 154.4 mg/kg and993.0 mg/kg and accounted for 22.6％ and 47.1％.With the increase of soil total P content,the content of soil total inor-ganic P and the raito of organic P,water-soluble P,Al-P to total P increased,and the ratio of soil O-P,Ca-P to total Pdecreased.Almost all the contents of inorganic phosphorus fraction,the water-soluble P and Al-P in Vegetation-growing concrete gunning（VGCG） were the highest,the O-P in Natural secondary forests （NSF） was the highest and Ca-P in Externalsoil spray seeding（ESS） was the highest among all the slope types.The relations between the contents of inorganic P fraction and available P showed that there were significant positive correlations between water-soluble P,Al-P and available P.There was significant positive correlation between water-soluble P and AI-P.Other inorganic P fractions had no significant correlation.The PAC （Phosphorus activation coefficient） of seven different types of slopes were all above 2.0％.It is indicated that the total P at various types of slopes in disturbed area of Xiangjiaba hydropower construction could be easily converted to available P,and there was enough available P for the need of vegetation growth.