木荷叶凋落物的分解及养分动态分析

Decomposition and nutrient dynamics of Schima superba leaf litter

采用网袋法研究木荷Schima superba叶凋落物分解及其养分动态。结果表明:木荷叶凋落物分解1 a后质量损失率为41.5%,分解率为0.001 6 d-1,完成50%分解以及完成95%分解所需的时间分别为1.36和5.47 a。分解过程中,氮存在一定的富集现象,磷处于波动的富集状态,钾呈现单调下降的变化趋势,而碳氮比和碳质量分数都是前期少量上升而后期下降。各营养元素的年释放率大小顺序依次为钾(81.3%)>碳(54.8%)>氮(35.7%)>磷(28.6%)。

Schima superba are cultivated widely in soutbern China. In order to know its material cycling in the plantation for better sustainable management, we studied the decomposition and nutrient dynamics of its leaf litter by the nylon bag method. The new leaf fall were collected in the 25-year-old plantation of Nanping City, in 1st of November of 2006, drying at 65 ℃ to constant weight, packed with 36 nylon bags, then replaced to the plantation＇s ground surface. Three bags were withdrawn once a month. Then determine weight loss rate, and N, P, K and C contents variation. Results showed that for leaf litter decomposition, the weight loss rate over one year was 41.5% with a decomposition coefficient of 0.001 6 d^-1. Also, 50% decomposition was estimated at 1.36 years while 95% was 5.47 years. During decomposition, N increased; P fluctuated but increased slowly; K steadily decreased; and C and carbon-nitrogen ratio increased slightly in the early stages, but decreased in later stages. Nutrient release was in the order： K（81.3%） 〉 C（54.8%） 〉 N（35.7%） 〉 P（28.6%）. [Ch, 1 fig. 2 tab. 10 ref.]