低丘红壤人工杉木林养分循环的初步研究

Preliminary studies on the nutrient cycling in the Chinese fir plantation on red earth in the low hill area:

在低丘红壤９年生人工杉木生态系统中，养分的流量和库存量均为Ｃａ最大，Ｐ最小。系统Ｎ、Ｐ、Ｋ、Ｃａ和Ｍｇ的输入与输出平衡都表现有盈余，其盈余量大小顺序为Ｎ＞Ｃａ＞Ｋ＞Ｐ＞Ｍｇ。在系统的林分中养分循环速率Ｐ最高，Ｎ最低，分别为１０．３％和２．６％，因而Ｐ的周转期最短，Ｎ的周转期最长，分别为９．７年和３８．５年；而土壤库中养分循环速率最高是Ｎ（３．１％），最低是Ｍｇ（０．６％），相应的周转期分别为３２．３年和１６６．７年。

The nutrient cycling in a 9 years old Chinese fir stand was studied on red earth in the low hill area. The flux and reservior of Ca was the biggest and that of P was the smallest of the nutrient elements in the Chinese fir ecosystem. The balance of nutrient elements was given according to the input and output. The order of the balance values was as follow: N>Ca>K>P>Mg. The inputs of these elements were more than their outputs. P cycling rate was the highest and that of N was the lowest in the Chinese fir forest. The cycling rate of P and N was 10.3% and 2 6%, respectively. Therefore, the periodic cycling time of P was the shortest (9 7 years) and that of N was the longest (38 5 years). Of the nutrient cycling rates in the soil pool N was the highest (3.1%) and Mg was the lowest (0 6%), and N periodic cycling time was 32 3 years and that of Mg was 166 7 years.