中文关键词秸秆生物炭土壤团聚体固碳贡献率 英文关键词strawbiocharsoil aggregatescarbon sequestrationcontribution rate

作者	单位	E-mail
徐国鑫	西南大学资源环境学院, 重庆 400715	1491860140@qq.com
王子芳	西南大学资源环境学院, 重庆 400715	zifangw@126.com
高明	西南大学资源环境学院, 重庆 400715
田冬	西南大学资源环境学院, 重庆 400715
黄容	西南大学资源环境学院, 重庆 400715
刘江	西南大学资源环境学院, 重庆 400715
黎嘉成	西南大学资源环境学院, 重庆 400715

中文摘要 揭示秸秆与生物炭还田对团聚体有机碳含量、分布、稳定性以及相对贡献率的影响，有利于明确秸秆与生物炭还田下土壤碳库的稳定性及其保护机制.采用田间试验方法研究了油菜/玉米轮作模式下，秸秆与生物炭还田对土壤团聚体及固碳特征的影响.结果表明：①秸秆与生物炭还田各处理均能提高土壤有机碳含量，其中生物炭还田（BC、16.88 g·kg^-1）、秸秆+生物炭还田（CSBC、17.37g·kg^-1）效果优于秸秆还田（CS、13.76 g·kg^-1）和秸秆+速腐剂还田（CSD、14.68 g·kg^-1）.②与对照（CK）处理相比，CS、CSD处理能显著地提高大团聚体（>2 mm）含量，增加率为94.00%~117.78%，同时显著提高了水稳性团聚体的平均重量直径（MWD）、几何平均直径（GMD）、R_0.25，降低了分形维数（D），提高了团聚体稳定性（P<0.05）.③随着团聚体粒径的增大，团聚体有机碳含量呈现先降低再增高然后再降低，且粉黏粒（<0.053 mm）对土壤有机碳贡献率最高（29.61%~42.18%），大团聚体有机碳贡献率最低（9.19%~17.81%）.除CSD处理外，CS、BC、CSBC处理降低了较大团聚体（2~0.25 mm）和微团聚体（0.25~0.053 mm）有机碳贡献率.秸秆还田促进土壤团聚作用效果优于生物炭还田，而生物炭还田提高团聚体有机碳含量效果优于秸秆还田，秸秆新碳主要向大团聚体内分配，秸秆+速腐剂还田还能促进较大团聚体内不同组分结合新碳，生物炭、秸秆+生物炭还田主要向微团聚体中富集. 英文摘要 The aim of this work is to understand the effects of straw and biochar return in soil on the content, distribution, stability, and relative contribution rate of organic carbon for soil aggregates, which could be used to better understanding the stability of the soil carbon pool and the protection mechanisms under straw and biochar return. In this study, a field experiment was conducted to study the effects of straw and biochar return on soil aggregates and carbon sequestration characteristics in a rape-maize rotation planting system. Five treatments, including a control (no organic material added, CK), straw (CS), straw and microorganism (CSD), Biochar (BC), half straw and half biochar (CSBC), were used. The results indicated that ① Straw and biochar could improve the content of soil organic carbon, and the BC and CSBC treatments increased it by 16.88-17.37 g·kg^-1, values higher than those with the CS and CSD treatments (13.76-14.68 g·kg^-1); ② Compared with the CK treatment, CS and CSD treatments could increase the stability of the aggregates through significantly increasing the content of macro-aggregate by 94.00%-117.78% and significantly increasing the mean weight diameter (MWD), geometric mean diameter (GMD), and R_0.25 of water stable aggregates, but reducing the D value (P<0.05); and ③ With the increase in aggregate particle size, the content of organic carbon in the aggregates decreased first and then increased. The contribution rate of soil organic carbon in silt and clay was the highest (29.61%-42.18%), and the contribution rate of organic carbon in the macro-aggregate was the lowest (9.19%-17.81%). In addition to the CSD treatment, the CS, BC, and CSBC treatments reduced the contribution of larger aggregates (2-0.25 mm) and micro-aggregates (0.25-0.053 mm). In general, the benefit of straw return was better than that of biochar in promoting soil aggregation. However, the application of biochar was better than straw in improving the aggregates organic carbon content. The newly generated carbon from straw degradation was mainly distributed in large aggregates. Straw with microorganisms could promote the combination of carbon by different components in the larger aggregates. The carbon from biochar and straw with biochar treatments were mainly concentrated in micro-aggregates.

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