水稻光合同化碳在土壤不同粒径、密度分组中的分配特征  

Distribution Characteristics of Rice Photosynthesized Carbon in Soil Aggregates of Different Size and Density

作　　者：李苗苗[1,2] 聂三安[2] 陈晓娟[2] 罗璐[1] 朱捍华[2] 石辉[1] 葛体达[2] 童成立[2] 吴金水[2] 

机构地区：[1]西安建筑科技大学环境与市政工程学院,西安710055 [2]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,长沙410125

出　　处：《环境科学》2013年第4期1568-1575,共8页Environmental Science

基　　金：中国科学院-国家外国专家局创新团队国际合作伙伴计划项目(KZCX2-YW-T07;20100491005-8);国家自然科学基金项目(41090283;40901124);湖南省自然科学基金项目(11JJ4030);中国科学院海外特聘研究员项目(2009Z2-10)

摘　　要：水稻生长影响土壤有机质在土壤及其各组分中的分布,是关系土壤有机质储量的重要因子.为量化水稻光合同化碳在土壤不同粒径和密度组分中的分布,进而为水稻土有机质积累持续机制与固碳潜力研究提供数据支撑,应用14C连续标记示踪技术,以当地主栽水稻品种"中优169"为供试作物,分别选取亚热带区4种典型稻田土壤,通过土壤有机质物理分组方法探讨了水稻根际输入的光合碳在土壤物理组分(粒径、密度)中的含量和分配特征.结果表明,水稻标记种植80 d后,250～2 000μm粒径的SOC14含量范围为118.23～309.94 mg.kg-1,SOC14/SOC的比例范围为0.52%～1.55%,均大于20～250μm、<20μm这2个粒径的SOC14含量和SOC14/SOC的比例,250～2 000μm、20～250μm这2个粒径的轻组组分的SOC14含量均显著大于相应的重组组分的SOC14含量,说明稻田生态系统通过水稻的根际沉积作用将有机碳(水稻光合同化碳)主要固定在大粒径的轻组组分中,从而提高了土壤有机碳含量.相关分析表明,250～2 000μm粒径与其轻、重组组分、<20μm粒径、20～250μm粒径的SOC14含量之间均呈显著性正相关,而<20μm、20～250μm粒径的轻组组分的SOC14含量之间呈极显著性负相关.Rice growth affects the distribution of organic matter in soils and soil fractions,and is thus an important factor to control the storage of soil organic matter.The aims of our study were to quantify the photosynthesized C in soil fraction pools of different size and density during the rice growth,and also to offer data evidence not only in the mechanisms of SOC accumulation,but also in C sequestration potential in paddy soils.Therefore,the microcosm experiment was carried out to quantify the input and distribution of photo-assimilated carbon（C） in soils size and density aggregates pools by using continuous 14 C labeling technique.Destructive samplings of rice（Oryza sativa） were conducted after labeling for 80 days.The allocation of 14 C-labeled photosynthates in soil C pools was examined in rice-planted soil over the 14 C labeling span using the size（250-2 000 μm,20-250 μm,20 μm） and density（light and heavy） fractionation procedure.The amount of 14 C in the soil organic C（SOC14） in the 250-2 000 μm particle size was dependent on the soils,ranged from 118.23 mg·kg-1 to 309.94 mg·kg-1,accounting for 0.52%-1.55% of its SOC,respectively,which was much larger than those of aggregates with the other two sizes（20-250 μm,20 μm）.Moreover,the amounts of SOC14in light fractions of 250-2 000 μm and 20-250 μm particle size aggregate were significantly greater than those in their heavy fractions（P0.05）.The data suggested that rice photosynthesize C mainly entered into the light fraction of 250-2 000 μm particle size aggregate by rhizodeposition,which enhanced the contents of SOC.There was a significant positive correlation between the light and heavy fraction and 250-2000 μm particle size aggregate,20-250 μm and 20 μm particle size aggregate of SOC14,although significant negative correlation between light fractions in20 μm,20-250 μm aggregates was observed.

关 键 词：水稻 光合同化碳 根际沉积 粒径 密度 土壤有机碳 14C连续标记 

分 类 号：X144[环境科学与工程—环境科学]