外源新碳对红壤团聚体及有机碳分布和稳定性的影响

发布时间：2018-02-26 11:35

本文关键词： 外源新碳 δC 水稳性团聚体红壤　出处：《环境科学学报》2017年06期 　论文类型：期刊论文

【摘要】：以中国科学院长期定位试验站的红壤为研究对象,通过室内模拟实验,利用δ~(13)C示踪方法,将稳定同位素碳(δ13C)标记的水稻秸秆添加入红壤,研究水稻秸秆添加对红壤水稳性团聚体分布及稳定性的影响,探索水稻秸秆腐解过程中有机碳在不同粒级团聚体中的动态变化以及分布规律.研究结果表明:未添加水稻秸秆的红壤(对照组),微团聚体(250μm)占主体,2000μm粒级水稳性团聚体含量最少.与对照相比,添加水稻秸秆后(试验组)促进了2000μm粒级水稳性团聚体的团聚.不同培养时期,2000μm水稳性团聚体增加了108.3%~270.3%,促使大团聚体占主体,显著提高了红壤水稳性团聚体的平均重量直径(MWD)、几何平均直径(GMD)、R0.25值,降低了分形维数(D)值,土壤结构明显得到改善.各粒级团聚体有机碳含量也显著得到提高,2000μm团聚体有机碳含量比对照组增加了14.7%~41.5%.土壤有机碳在53μm粒级团聚体中分布随着粒级的增大而增大,即2000μm2000~250μm250~53μm.不同粒级团聚体δ13C值动态变化显著,有机碳的周转速率增大.外源新碳前期主要分配在2000μm、250~53μm粒级团聚体中,并促进了原有机碳的分解,后期主要分配在微团聚体中.红壤大团聚体有机碳含量与团聚体稳定性呈极显著的相关关系(p0.01).
[Abstract]:In this paper, the red soil of the long term Positioning Test Station of the Chinese Academy of Sciences was used as the research object. The stable isotope carbon (未 13 C) labeled rice straw was added to the red soil by using the 未 ~ (13) ~ (13) C tracer method. The effects of rice straw addition on the distribution and stability of water-stable aggregates in red soil were studied. The dynamic changes and distribution of organic carbon in different grain-grade aggregates during the decomposition of rice straw were investigated. The results showed that the red soil without rice straw (control group, microaggregate 250 渭 m) accounted for 2000 渭 m of grain water stability. The content of sexual aggregates is the least. The addition of rice straw promoted the agglomeration of 2000 渭 m water stable aggregates, and 108.3 渭 m water stable aggregates increased 108.3 渭 m in different culture periods, which promoted the large aggregates to occupy the main body. The mean weight diameters of water-stable aggregates in red soil and the geometric mean diameters of GMDD ~ (0. 25) and the fractal dimension (D) were increased significantly, respectively. The soil structure was obviously improved, and the organic carbon content of the aggregates at the grain level increased significantly by 14.775 渭 m and 41.5% than that of the control group. The distribution of soil organic carbon in 53 渭 m aggregates increased with the increase of the grain size. That is, 2000 渭 m 2000 ~ 250 渭 m 250 渭 m ~ 53 渭 m. The 未 ~ (13) C value of different grain-grade aggregates changed significantly, and the turnover rate of organic carbon increased. The early stage of exogenous new carbon was mainly distributed in 53 渭 m agglomerates of 2000 渭 m ~ 250 渭 m, and promoted the decomposition of proto organic carbon. The content of organic carbon in the red soil aggregate was significantly correlated with the stability of the aggregates in the late stage, and there was a significant correlation between the content of organic carbon and the stability of the aggregates.
【作者单位】：陕西省土地工程建设集团有限责任公司;国土资源部退化及未利用土地整治工程重点实验室;中国科学院南京土壤研究所;
【基金】：国家科技支撑计划课题(No.2014BAL01B01) 国土资源部公益性行业科研专项(No.201411008-3) 陕西省重点科技创新团队计划项目(No.2016KCT-23)~~
【分类号】：S152.4;S153.6

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