马占相思近熟林养分循环研究

研究了广西高峰林场11年生（近熟林）马占相思人工林10种营养元素生物循环的特点。结果表明：（1）马占相思不同器官营养元素含量以树叶（叶状柄）为最高，树干最低；各器官中大量营养元素含量以N最高，其次是Ca或K，然后是Mg，P最低；微量元素含量则以Mn和Fe最高，其次是Zn和B，Cu最低；（2）林分营养元素贮存量为2609．28kg／hm^2，乔木层、灌木层、草本层和凋落物层分别占83．95％、4．43％、1．71％和9．91％，林木中不同器官营养元素贮存量排序为干材〉树枝〉树根〉干皮〉树叶．（3）林分年吸收量、归还量、存留量分别为388．47、195．51和192．96kg／（hm^2·a），10种元素的循环系数为0．39～0．78，循环速率依次为Mn〉Zn〉Mg〉P〉Ca〉Fe〉N〉Cu〉K〉B。

Nutrients cycling in near-mature plantation of Acacia mangium

The biological cycle of 10 nutrient elements in the 11-year-old Acacia mangium plantation(near-mature)was studied in Gaofeng forest farm of Guangxi.The results were as follow:(1) The nutrient contents of Acacia mangium stand were different in different organs,highest in the leaves(phyllode) and lowest in the stems.The content of N was the highest,K and Ca the second,Mg and P were the lowest in macro-elements,while Mn and Fe were the highest,B and Zn the second,and Cu was lowest in micro-elements.(2)The tota...