思茅松人工林土壤有机碳库特征

Soil organic carbon pool characteristics of Pinus kesiya var. langbianensis plantation

为探讨思茅松人工造林对土壤有机碳库的影响,以云南省普洱市思茅区8种定植模式及7个林龄的思茅松人工林为研究对象,对0～ 50 cm土层土壤有机碳质量分数及密度进行调查分析.结果表明：1）思茅松人工林土壤有机碳质量分数随土壤深度的增加而降低,8种定植模式13a思茅松人工林0～50 cm土壤有机碳质量分数皆大于思茅松天然林;不同林龄思茅松人工林土壤有机碳质量分数在4～10a处于降低阶段,12a以后开始升高.2）土壤可溶性碳质量分数随土壤深度的增加而减小,土壤微生物量碳主要集中于0 ～10 cm土层.3）8种定植模式思茅松人工林土壤有机碳密度在64.48 ～ 84.30 t/hm2之间,其中2m＆#215;4m定植模式最大,1m＆#215;1m模式最小;土壤可溶性碳密度数值范围为0.30 ～0.42 t/hm2,土壤微生物量碳密度为0.49 ～ 1.29 t/hm2;4～ 14 a思茅松人工林土壤有机碳密度和可溶性碳密度随林龄的增加呈现先降后升的特点,14a时土壤有机碳密度达92.14 t/hm2,可溶性碳密度达0.42 t/hm2;土壤微生物量碳密度10a时最大,达0.92 t/hm2.研究表明思茅松人工林具有较强的土壤碳积累能力.

In Simao district of Pu＇ er City of Yunnan Province, we chose a series of plantations involving eight different planting densities and seven stand ages as the research objects. Through measuring the soil organic carbon contents and carbon densities （0 - 50 cm depth） , the effects of Pinus kesiya var. langbianensis planting on soil organic carbon （SOC） were investigated and analyzed. The results were as follows： 1 ） The SOC contents of P. kesiya var. langbianensis plantations decreased with the soil depth. Under all the eight planting densities, in the stand age of 13 years, the SOC contents （0 -50 cm depth） were higher than those of natural P. kesiya var. langbianensis forest. As far as the ages of plantations were concerned, from the 4th year to the 10th year after planting, the contents of SOC were in a declining stage, and began to increase since the 12th year. 2） Vertically, the dissolved organic carbon （DOC） decreased with the increase of soil depth, and the accumulated spatial distribution of microbial biomass carbon （MBC） was at the layer of 0 - l0 cm. 3） The SOC densities of eight involved planting densities rangedfrom 64.48 t/hm2 to 84.30 t/hm2 , among which, the SOC density of the planting density of 2 m × 4 m was the highest, whereas that of 1 m ×1 m was the lowest. The values of DOC density and MBC density ranged from 0.30 to 0.42 t/hm2 and from 0.49 to 1.29 t/hm2 , respectively. Both SOC density and DOC density of studied plantations from 4 years old to 14 years old showed the characteristies of decreasing and then increasing as the planting age increased. The SOC density and DOC density of 14 years old plantation were 92. 14 and 0.42 t/hm2 , respectively, and the peak value of MBC density occurred at the plantation of 10 years old, which was 0.92 t/hm：. The results of this study verified that P. kesiya var. langbianensis plantation has promising ability of carbon storage.