Journal of Integrative Agriculture ›› 2019, Vol. 18 ›› Issue (7): 1496-1507.DOI: 10.1016/S2095-3119(19)62643-2

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  • 收稿日期:2018-11-30 修回日期:2019-01-08 出版日期:2019-07-01 发布日期:2019-07-01

Soil organic carbon associated with aggregate-size and density fractions in a Mollisol amended with charred and uncharred maize straw

GUAN Song1, LIU Si-jia1, LIU Ri-yue1, ZHANG Jin-jing1, REN Jun2, CAI Hong-guang2, LIN Xin-xin1   
  

  1. 1 Key Laboratory of Soil Resource Sustainable Utilization for Commodity Grain Bases of Jilin Province, College of Resource and Environmental Science, Jilin Agricultural University, Changchun 130118, P.R.China
    2 Jilin Academy of Agricultural Sciences, Changchun 130033, P.R.China
  • Received:2018-11-30 Revised:2019-01-08 Online:2019-07-01 Published:2019-07-01
  • Contact: Correspondence ZHANG Jin-jing, Tel: +86-431-84532955, Fax: +86-431-84531264, E-mail: zhangjinjing@126.com; REN Jun, Tel: +86-431-87063030, Fax: +86-431-87063028, E-mail: renjun557@163.com
  • About author:GUAN Song, Mobile: +86-13504467990; E-mail: guansong8888 @163.com;
  • Supported by:
    This work was supported by the National Key Research and Development Program of China (2017YFD0200801 and 2017YFD0300602), the National Natural Science Foundation of China (41471196), the Science and Technology Development Project of Jilin Province, China (20170101162JC) and the Science and Technology Project of the Education Department of Jilin Province, China (JJKH20170313KJ).

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Abstract:

Straw return has been strongly recommended in China, whereas applying biochar into soil is considered to provide more benefits for agriculture as well as the environment.  In this study, a five-year (2011−2015) field experiment was conducted to evaluate the effects of uncharred maize straw amendment (MS) and charred maize straw amendment (charred MS) on organic carbon (C) contents in bulk soil and in various soil aggregate-size and density fractions.  Compared to no amendment (CK), the bulk soil organic C content significantly improved by 9.30% for MS and by 23.4% for charred MS.  Uncharred and charred maize straw applied annually at a consistent equal-C dosage resulted in 19.7 and 58.2% organic C sequestration efficiency in soil, respectively, after the five years of the field experiment.  The percentages of macroaggregates (>0.25 mm) and occluded microaggregates (0.25−0.053 mm) obviously increased by 7.73 and 18.1% for MS and by 10.7 and 19.6% for charred MS, respectively.  Moreover, significant incremental increases of 19.4 and 35.0% in macroaggregate-associated organic C occurred in MS and charred MS, respectively.  The occluded microaggregates associated organic C significantly increased by 21.7% for MS and 25.1% for charred MS.  Mineral-associated organic C (<0.053 mm) inside the macroaggregates and the occluded microaggregates obviously improved by 24.7 and 33.3% for MS and by 18.4 and 44.9% for charred MS.  Organic C associated with coarse particulate organic matter (POM) within the macroaggregates markedly increased by 65.1 and 41.2% for MS and charred MS, respectively.  Charred MS resulted in a noteworthy increment of 50.4% for organic C associated with heavy POM inside the occluded microaggregates, whereas charred MS and MS observably improved organic C associated with heavy POM inside the free microaggregates by 36.3 and 20.0%, respectively.  These results demonstrate that uncharred and charred maize straw amendments improve C sequestration by physically protecting more organic C in the macroaggregates and the occluded microaggregates.  Compared to the feedstock straw amendment, charred maize straw amendment is more advantageous to C sequestration.