三种整地措施下尾巨桉人工林碳储量及其分配格局

以不炼山＋人工穴垦、不炼山＋机械带垦和炼山＋机械全垦3种不同整地组合下的2.5年生尾巨桉人工林为对象,对其碳储量及其分配格局进行研究。结果表明：(1)3种整地组合下尾巨桉各器官碳含量平均值为44.37％~57.42％,大小顺序为叶>干>枝>根>皮,带垦最大(51.21％),炼山全垦最小(49.95％)；不同整地组合尾巨桉人工林林下地被物层的碳含量均无显著差异(P>0.05)；土壤层(0~100 cm)碳含量均随土层深度的增大而减小,各层土壤平均碳含量总体趋势表现为带垦>炼山全垦>穴垦。(2)穴垦、带垦、炼山全垦措施下乔木层总碳储量依次为18.01、30.49和23.56 t.hm-2,各器官碳储量大小顺序为干>根>叶>枝>皮；除皮外,其余器官碳储量排序均为带垦>炼山全垦>穴垦。(3)尾巨桉人工林生态系统的总碳储量表现为带垦(197.03 t.hm-2)>炼山全垦(161.16t.hm-2)>穴垦(144.77 t.hm-2)；不同整地措施碳储量分配格局均为土壤层>植被层>枯落物层。土壤层和乔木层碳储量均是带垦最大,在整个生态系统碳储量中处于主导地位,占整个系统碳储量在93％以上；不同整地组合措施对枯落物层的碳储量无显著影响。因此,从提高尾巨桉林分系统碳储量方面考虑,在雷州半岛及相似立地条件地区进行尾巨桉人工林造林时宜采取不炼山＋机械带垦的整地组合方式。

Carbon storage and its distribution in Eucalyptus urophylla × E. grandis plantations under three different soil preparation measures

To evaluate the carbon storages and their allocations in 2.5-year-old Eucalyptus urophylla&#215;E. grandis(DH_-3229)plantation in Guangdong, three kinds of soil preparation(no controlled burning and dig hole, no controlled burning and furrowing, controlled burning and full cultivation)mode were selected, field investigation and indoor analysis methods were adopted to measure the carbon content in different organs. The main results were as follow:(1)The average carbon content in different organs of DH_-3229 was 44.37%-57.42%, and the carbon content sequence was leaf > truck > branch > root > bark. No significant difference(P<0.05)was observed in carbon content among the shrub, herb and litter layers of the DH_-3229 plantations with different soil preparation measures. Carbon content in the soil layer(0-100 cm)decreased with the increase of soil depth.(2)The carbon storage of no controlled burning and dig hole, no controlled burning and furrowing and controlled burning and full cultivation in tree layer were 18.01, 30.49 and 23.56 t·hm^-2. Carbon storage in various organs showed the order: stem > root > leaf > branch > bark. Except for the bark, the order of carbon storage in other organs under three different soil preparation measures was furrowing soil preparation > all reclamation soil preparation > dig hole soil preparation.(3)The total ecosystem carbon storage of DH_-3229 plantations under different soil preparation measures was 144.77 t·hm^-2 (dig hole), 197.03 t·hm^-2(burning)and 161.16 t·hm^-2(all reclamation soil preparation), and the carbon storage or der of different soil preparation measures in different layers appeared: soil layer>vegetable layer>litter layer. Carbon storage allocations in tree and soil layer of furrowing soil preparation were significantly larger than all reclamation soil preparation and dig hole soil preparation. The carbon storages of tree stratum and soil layer were the dominant part in carbon storage of the whole ecological system, which accounted for more than 93% of the carbon storage in the ecosystem. However, different combinations of measures on soil preparation have no significant effects on C storage allocations in the litter layer. Therefore, it appears furrowing soil preparation may be a more appropriate method to improve carbon storage of the DH_-3229 in the Leizhou Peninsula or other areas with similar site conditions.