摘要
研究短期不同秸秆还田方式对农田黑土不同粒径团聚体内有机碳含量和红外光谱特征的影响,为优化秸秆还田方式和提高农田生态系统土壤固碳潜力提供理论依据。基于建立在海伦站内的不同秸秆还田方式田间定位试验,试验共6种处理:(1)S0,翻耕20 cm,秸秆不还田;(2)S1,翻耕20 cm,半量秸秆(5 t·hm^-2)还田;(3)S2,翻耕20 cm,全量秸秆(10 t·hm^-2)还田;(4)S3,深翻35 cm,全量秸秆(10 t·hm^-2)深混还田;(5)S4,免耕,全量秸秆(10 t·hm^-2)覆盖还田;(6)S5,翻耕20 cm,全量秸秆(10 t·hm^-2)燃烧后产物还田。利用水稳性团聚体分级和傅里叶红外光谱技术(FTIR)研究了不同秸秆还田方式下全土及各粒级团聚体内有机碳的含量和红外光谱特征。研究发现,与S0处理相比,不同秸秆还田方式不同程度的提升了黑土表层总有机碳含量,表现为S2>S1>S4>S5>S3>S0,各处理土壤中>2 mm和2~0.25 mm粒级团聚体所占比例分别提升了16.4%~112.9%和19.0%~29.4%,其内部的有机碳含量分别提高了14.4%~55.5%和32.7%~54.7%。与S0处理相比,不同的秸秆还田方式使土壤有机碳的脂肪族-CH红外吸收峰相对面积增加,芳香族C=C红外吸收峰相对面积减少。相关分析和主成分分析表明,全土、>2 mm和2~0.25 mm的团聚体中有机碳含量与脂肪族相对峰面积呈极显著正相关关系,与芳香族相对峰面积呈显著负相关关系(P<0.05);而<0.053 mm团聚体内的有机碳含量与脂肪族相对峰面积呈显著负相关关系,与芳香族相对峰面积呈显著正相关关系(P<0.05),说明土壤大团聚体中主要是结构简单、易分解组分的碳,而小粒径的微团聚体中以稳定性较强的芳香族碳为主,短期秸秆还田能促进大团聚体形成,提高土壤有机碳中脂肪族碳的含量及团聚体对碳的保护能力,更利于碳的固存。秸秆还田措施中采用20 cm翻耕秸秆全量还田对于提高表层黑土有机碳含量和稳定性具有较好的效果。
The effects of short-term different straw returning managements on the content and infrared spectrum characteristics of organic carbon within aggregates were investigated in an arable Mollisols.The results were expected to provide a theoretical basis for optimizing the straw returning practices and enhancing the potential of organic carbon sequestration.Six field treatments with different patterns of crop returning were established in the Hailun Station as follows:(1)S0,plowing 20 cm,crop straw removal;(2)S1,plowing 20 cm,crop straw returning at 5 t·hm^-2;(3)S2,plowing 20 cm,crop straw returning at 10 t·hm^-2;(4)S3,deep plowing 35 cm,crop straw returning at 10 t·hm^-2 at 20-35 cm layer;(5)S4,no-tillage,10 t·hm^-2crop straw mulching at the surface;(6)S5,plowing 20 cm,10 t·hm^-2 crop straw after burning.The water-stable aggregate fraction and Fourier Infrared Spectroscopy(FTIR)methods were utilized to analyze the characteristics of infrared spectrum of organic carbon in both bulk soil and aggregate-sized fractions under different straw returning managements.Our results showed that compared to S0 treatment,different straw returning managements increased the surface soil organic carbon contents in an order of S2>S1>S4>S5>S3>S0.The mass percentages of>2 mm and 2-0.25 mm aggregates increased by 16.4%-112.9%and 19.0%-29.4%,respectively under different straw returning managements.The content of organic carbon within>2 mm and 2~0.25 mm aggregate increased by 14.4%-55.5%and 32.7%-54.7%,respectively.Compared to the S0 treatment,the infrared absorption peaks of aliphatic-CH increased,and aromatic C=C decreased after short-term straw returning.Correlation analysis and principal component analysis showed that the content of organic carbon was positively correlated with the relative peak area of aliphatic,but negatively correlated with the relative peak area of aromatic(P<0.05)within>2 mm and 2-0.25 mm aggregates.On contrast,the organic carbon contents were negatively correlated with the relative peak area of aliphatic group and positively correlated with the relative peak area of aromatic group within<0.053 mm aggregate.These results indicates that the organic carbon within macroaggregates is mainly composed of simply-structured and easily-decomposed organic matter,while the organic carbon within microaggregates is mainly composed of aromatic carbon with higher stability.Long-term different straw returning managements are suggested to be beneficial in increasing SOC contents,promoting the formation of macroaggregates,enhancing the stability of aggregates and carbon sequestration.The crop straw returning at 10 t·hm-1 combined with 20 cm soil tillage management is proposed to be the most effective measure to increase surface SOC and its stabilization in the Mollisol region.
作者
盛明
龙静泓
雷琬莹
郝翔翔
李娜
韩晓增
李禄军
SHENG Ming;LONG Jinghong;LEI Wanying;HAO Xiangxiang;LI Na;HAN Xiaozeng;LI Lujun(Key Laboratory of Mollisols Agroecology,Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,Harbin 150081,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《土壤与作物》
2020年第4期355-366,共12页
Soils and Crops
基金
国家重点研发计划项目(2016YFD0300802-01)
中国科学院前沿科学研究重点计划项目(QYZDB-SSW-SYS02,ZDBS-LY-DQC017-01)
中国科学院青年创新促进会项目(2016211)
中国科学院东北地理与农业生态研究所优秀青年人才项目资助.
关键词
土壤有机碳
团聚体
傅里叶变换红外光谱
秸秆还田
黑土
soil organic carbon
aggregate
Fourier Infrared Spectroscopy
straw returning
Mollisol
