不同植被覆盖对土壤有机碳矿化及团聚体碳分布的影响_1

第24卷第6期2010年12月水土保持学报

Jour nal of Soil and W ater Conserv ation Vo l.24No.6Dec.,2010

收稿日期:2010-07-15

基金项目:国家科技支撑计划课题(2008BAB38B02-3,2006BAD05B01-02);西南大学生态学重点学科 211工程 ;西南大学研究生科技

创新基金项目(ky2008007)

作者简介:罗友进(1984-),男,博士研究生,研究方向为土地利用与生态变化。E -mail:luoyoujin1984@

通讯作者:魏朝富(1962-),男,研究员,博士生导师,主要从事土壤物理学方面研究。E -mail:w eicf@s

不同植被覆盖对土壤有机碳矿化及团聚体碳分布的影响

罗友进,赵光,高明,魏朝富,赵丽荣

(三峡库区生态环境教育部重点实验室,西南大学资源环境学院,重庆400715)

摘要:植被覆盖通过其输入有机物料的差异影响着土壤养分和微生物活性,进而对其土壤的团聚过程和有

机碳的矿化产生影响。该文通过对重庆缙云山四种植被类型覆盖(灌草丛、楠竹林、常绿阔叶林、针阔混交

林)下土壤团聚体碳分布以及土壤有机碳矿化的分析,探讨了植被覆盖对这两者的影响以及两者的相互联

系。植被覆盖影响着土壤有机碳矿化过程和团聚体碳分布。就土壤有机碳矿化累积量(42天)而言,表现

为灌草丛>常绿阔叶林>针阔混交林>楠竹林。不同植被覆盖土壤有机碳日均矿化速率在培养前期(前8

天)差异较大,之后则趋于一致。除灌草丛土壤外,楠竹林、常绿阔叶林和针阔混交林覆盖土壤团聚体均以

0.25~2mm 和<0.25mm 团聚体为主,其总量达到65%以上。土壤团聚体平均重量直径表明灌草丛土壤

结构稳定性要优于其它植被覆盖土壤,而楠竹林土壤结构稳定性最差。除灌草丛土壤外,<0.25mm 团聚

体是土壤有机碳的主要载体;其次是0.25~2mm 团聚体。简单相关和多元回归分析,表明土壤有机碳矿

化系数与<0.25mm 团聚体含量成负相关,与>5mm 团聚体有机碳库成正比。因此,土壤团聚体对有机

碳保护作用是土壤有机碳分配和矿化分解综合作用的结果。

关键词:植被覆盖;团聚体;有机碳;矿化

中图分类号:S152.4;S153.62 文献标识码:A 文章编号:1009-2242(2010)06-0117-06

Organic Carbon Distribution in Aggregates and Soil Organic Carbon

Mineralization in Different Vegetation Covering

LU O You -jin,ZH AO Guang,GA O Ming,WEI Chao -fu,ZH AO L-i rong

(K ey L abor ato ry of Eco -envir onments in T hr ee Gor ges Reser voir Region,M inistr y of Education,

College of Resour ces and Envir onment,Southw est Univ er sity ,Chong qing 400715)

Abstract:Soil nutrient distribution and microbial activities w er e influenced by vegetation cov ering,throug h chang e org anic carbon input,and then altered soil ag gr eg ation and o rganic carbo n mineralization.Soils w er e sampled fro m four different veg etatio n covering (included shrub forest,bamboo forest,br oadleaf forest,and mixed forest)in Jinyun m ountain,in Chongqing municipality.Soil aggr eg ates w ere separated into four ag -g regates (<0.25,0.25~2,2~5,>5m m)by w et sieve.Soil org anic carbon mineralization w as measured by incubation exper im ents.The cum ulative am ount of soil o rganic carbon m ineralizatio n amo ng different veg -etation covering w as in the order of shr ub forest>bro adleaf forest>mixed forest>bamboo for est.T he r ela -tive significant differences of mineralization rate w ere observ ed among vegetation co vering in the ear ly period of incubation.T he 0.25~2m m and <0.25m m agg regates w er e the main composition of so il in bambo o for -est,br oadleaf forest,and mix ed for est.The r esults of soil agg reg ate w eig ht mean diam eter indicated that soil structure stability w as best in shrub forest and w orst in bambo o forest.Ex cept in shrub for est,soil org anic carbon w as mostly distributed in <0.25mm ag gregate and follow ed by 0.25~2mm aggr eg ate.T he org anic carbon mineralization coefficient had neg ative linear relationship w ith amount o f <0.25m m agg regate and positiv e linear relationship w ith or ganic car bon stock of >5m m ag gregate by simple correlate and linear re -g ressio n analysis.In conclusion,the effect of ag gregates protecting o rganic carbo n in the soil is the integra -tion o f distribution and mineralization of o rganic carbo n.

Key words:vegetation cov ering;agg reg ate;org anic carbon;m ineralizatio n