【摘要】 对湖南省3种不同密度类型的马尾松飞播林分的养分循环进行了研究.结果表明:各组分营养元素的含量均以树叶最高,树干最低,在各组分中大量元素以N、K、Ca的含量较高,而P和Mg的含量较低;微量元素以Mn的含量为最高,Cu的含量为最低.单株林木营养元素的积累量随着林分密度的增大而减小,低密度林分营养元素积累量分别是中密度、高密度林分的2.75倍和4.04倍.不同密度单株林木各营养元素积累量依次为N>K、Ca>Mg>P>Mn>Fe>Zn>Cu.随着林分密度的增加,乔木层营养元素的积累量逐渐增大,地被层所积累的营养元素量有减少的趋势.林分年净积累量随着林分密度的增加而增加,各元素的净积累量以N最大,Cu最小.各种元素的吸收量、存留量都随着林分密度的增大而增大.营养元素的循环速率也因林分密度的增大而逐渐变小,并且大量元素的循环速率要高于微量元素.更多还原

【Abstract】 The nutrient cycle in three types of standing density of planeseeding Pinus massoniana of Hunan Province was studied in this paper. The results show that the nutrient contents are the highest of degree in leaves and lowest in stems; that the contents of N、K and Ca are higher than those of P、Mg as to macroelements; that the content of Mn is the highest and Cu the lowest as to microelements; that nutrient accumulation of individual trees decreases with the increase of the standing density and low density forests’ accumulation is respectively 2.75 and 4.04 times as much as that of medium density and high density; that in differentdensity plantations, the amount of nutrient accumulation is in the sequence of N>K、Ca>Mg>P>Mn>Fe>Zn>Cu; and that with the density increasing, nutrient accumulation quantities of arbor layer would increase, but opposite is the ground layer. The results also show that annual net accumulation increases with the increase of the standing density; that among various elements, N’s annual net accumulation is the highest and Cu’s the lowest; and that every element’s absorption and preservation will increase when the stand density is added; however, the cycling velocity of nutrient elements will slow down and the cycling velocity of macroelements is faster than that of microelements.更多还原