【摘要】 凋落物的转化在维持森林生态系统养分平衡中具有重要意义。以重庆铁山坪典型酸雨林区的马尾松(Pinus massoniana)、香樟(Cinnamomum camphora)及马尾松-香樟混交林为对象,通过原位布置分解袋法,动态监测各林型凋落物的分解速率、pH、有机碳、全氮(TN)、全磷(TP)和全钾(TK)含量等指标,探究该林区三种林型凋落物的腐解特征。结果表明,该林区凋落物的分解速率呈前期快后期慢的特点;从林型来看,前期C:N最低的香樟凋落物的分解速率最高;从整体上看,凋落物分解速率与其有机C含量(R=0.61, P<0.05)和C:N值(R=0.32, P<0.05)呈显著正相关。分解过程中,各林型凋落物的有机碳含量和C:N分别呈下降和先升后降的趋势, TK含量均为先降低后升高;香樟凋落物的TN含量呈下降趋势,而混交林和马尾松林则呈初期显著降低后期略升高的特点;香樟凋落物的TP含量为先升高后稳定,其余林型则整体无显著变化。分解过程中,林木类型可显著影响凋落物的pH、TN、TP、TK及C:N比,但对凋落物的分解速率无显著影响。更多还原

【Abstract】 The return and transformation of tree litter are critical processes in keeping nutrient balance for the forest ecosystem. In this study, within the acid rain zone of Tieshanping forest area in Chongqing, an in-situ tree litter decomposition experiment of a year was conducted in 3 representative forest types, including the Pinus massoniana, Cinnamomum camphora, and mixed district of these two trees, and then the decomposing rate, pH, and the contents of organic carbon, total nitrogen(TN), total phosphorus(TP), and total potassium(TK) of the tree litter were dynamically measured, aiming to reveal the effect of forest types on the decomposing characteristics of tree litter in this subtropical forest areas. The results indicated that the higher litter decomposing rate in all forest types was observed in the initial decomposing stage, which was the highest in the Pinus massoniana with the lowest C: N value. Based on an overall analysis of the decomposition period, the litter decomposing rate showed a positive relationship with the organic C concentration(R = 0.61, P < 0.05) or the C: N(R = 0.32, P < 0.05) of the litter. During the decomposition, the organic C content and C: N of the tree litter in all forest types showed increasing and increasing followed by decreasing tendencies, respectively, and the TK content exhibited an initial decrease and following increase tendency. Furthermore, the litter TN content gradually decreased in the Pinus massoniana forest, while it showed a tendency of initial decrease and later increase in the other two forest types; the litter TP content in the Pinus massoniana forest increased at the early stage and then unchanged, which was constant in the other two forest types. During the decomposition, forest type had significant effects on the pH, TN, TP, TK, and C: N of the tree litter but showed no significant effect on its decomposition rate.更多还原