三倍体毛白杨不同有机残体分解特征的研究

为探明三倍体毛白杨纸浆林林地养分状况,寻求可能的养分输入途径,实现林地长期生产力的维持和提高,采用网袋法研究了三倍体毛白杨(Populus tomentosa)落叶、枝条(直径小于0.5 cm)、细根(直径小于2 mm)以及树皮的分解率和分解过程的变化规律。结果表明:4种残余物在一年中分解速率的变化总体表现为快—慢—快的节律,但位于地下的细根分解过程与位于地表的落叶、枝条和树皮有所不同,方差分析表明,不同阶段的分解率之间存在显著差异;4种残余物的分解速率不同,实验后期细根的分解率为42.5%,落叶的分解率为30.5%,树皮的分解率为26.0%,枝条的分解率为20.9%,不同残余物的分解速率之间存在显著性差异。这充分说明三倍体毛白杨纸浆林中不同有机残体在不同分解阶段具有不同特征,今后应进一步研究其养分释放规律,采取针对性措施加快其分解,以不断提高立地生产力。

Study on the Characteristics of Different Organic Residue Decomposition of Triploid Populus tomentosa

Litter such as leaves and branches are the main source of nutrients and energy in forest ecosystems,and their decomposition process and rate influence nutrient cycling and energy flow. To verify the status of nutrients of triploid Populus tomentosa pulp plantations,and seek feasible ways to supply more nutrients to maintain and improve long-term soil productivity,a litterbag method was employed to study the rate and law of the decomposition process of fine branches （Ф 〈 0.5 cm）,leaves,fine roots （Ф 〈 2 mm） and bark. After one year,the decomposition process patterns of leaves,bark and fine branches on the soil surface were similar,but the decomposition of fine roots differed as they were embedded in the soil. At the end of the experiment,the decomposition rates of fine roots,leaves,bark and fine branches were 42.5%,30.5%,26.0% and 20.9%,respectively. These results showed that different residues had different characteristics and needed to employ proper measures to promote decomposition and improve site productivity.