马尾松人工林采伐剩余物生物量及养分贮量

Biomass and nutrient storage of logging residues of Pinus massoniana plantation

研究马尾松人工林采伐剩余物各组分生物量和养分贮量分配特征,可为其地力维护研究提供基础数据,为人工林的科学经营和生态管理提供理论依据。在广西南部马尾松人工林皆伐林地采用样方收获法获取采伐剩余物各组分生物量,测定其养分含量并计算养分贮量。结果表明:马尾松人工纯林皆伐后林地采伐剩余物生物量为39.1 t·hm-2,碳、氮、磷、钾、钙和镁贮量分别为18303、101.2、8.3、73.4、96.0和24.7 kg·hm-2。不同组分间比较,生物量和碳贮量均是小枝最高(分别占总量的25.3%和23.3%),其次是大枝(21.7%和21.1%)和主根(17.1%和18.5%),粗根(11.5%和12.4%)和叶(9.2%和9.1%)也较高;氮、磷、钾、钙和镁贮量排在前三位的组分均是叶、小枝和大枝(三者之和分别占各养分总量的70.5%、76.5%、72.2%、76.2%和72.6%),其次为主根和粗根;而中根、小根和细根无论是生物量还是各养分贮量均很低。马尾松人工林采伐剩余物的生物量和养分储量庞大,尤其是残留在地表的枝和叶,因此保留采伐剩余物的林地更新方式对于维护其林地生产力具有重要意义。

To understand soil productivity maintenance and provide reliable scientific basis for plantation management, biomass and nutrient allocation in different components of logging residues were examined in the clearcutting land of a 31-year-oldPinus massoniana plantation. We measured biomass and nutrient concentration of logging residue’s components, and then calculated nutrient storage. The results showed that the total biomass of logging residues was 39.1t·hm-2, and the storage of carbon, nitrogen, phosphorus, potassium, calcium and magnesium was 18303, 101.2, 8.3, 73.4, 96.0 and 24.7 kg·hm-2, respectively. Among different components, the biomass and carbon storage were in the order of sprig （accounting for 25.3% and23.3% of total biomass and carbon storage, respectively） 〉 branch （21.7% and 21.1%） and taproot （17.1% and 18.5%） 〉 coarse root （11.5% and 12.4%） and leaf （9.2% and 9.1%）. Nitrogen, phosphorus, potassium, calcium and magnesium were mainly stored in sprig, branch, and leaf （the sum of those components were 70.5%, 76.5%, 72.2%, 76.2% and 72.6%, respectively）, followed by taproot and coarse root. The middlesized root, small root and fine root had the lowest biomass and nutrient storage. The biomass and nutrient storage of logging residues were enormous, especially in branch and leaf. Therefore, retaining logging residues during forest regeneration is important for forest productivity maintenance.