Journal of Integrative Agriculture ›› 2021, Vol. 20 ›› Issue (1): 236-247.DOI: 10.1016/S2095-3119(20)63347-0

所属专题: 农业生态环境-土壤微生物合辑Agro-ecosystem & Environment—Soil microbe

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  • 收稿日期:2020-01-01 出版日期:2021-01-01 发布日期:2020-12-13

Effects of long-term straw return on soil organic carbon fractions and enzyme activities in a double-cropped rice paddy in South China

HUANG Wan, WU Jian-fu, PAN Xiao-hua, TAN Xue-ming, ZENG Yong-jun, SHI Qing-hua, LIU Tao-ju, ZENG Yan-hua   

  1. Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education/Collaborative Innovation Center for the Modernization Production of Double Cropping Rice/College of Agronomy, Jiangxi Agricultural University, Nanchang 330045, P.R.China
  • Received:2020-01-01 Online:2021-01-01 Published:2020-12-13
  • Contact: Correspondence ZENG Yan-hua, Tel: +86-791-83850663, E-mail: zyh74049501 @163.com
  • About author:HUANG Wan, E-mail: huangwan172@163.com;
  • Supported by:
    This work was supported by the National Key Research and Development Program of China (2017YFD0301601), the China Postdoctoral Science Foundation (2016M600512), the Open Project Program of State Key Laboratory of Rice Biology, Ministry of Science and Technology, China (20190401), and the Jiangxi Province Postdoctoral Research Project Preferential Grant, China (2017KY16).

摘要:

长期秸秆还田是提高农田土壤有机碳储量的重要碳源,秸秆焚烧还田在我国南方也屡见不鲜。然而,长期稻草管理对土壤有机碳组分、酶活性及其相互关系的影响,以及其影响是否存在季节差异却尚未明确。我们基于2009年开始建立的长期定位试验平台,通过设置3个N、P、K等养分输入(包括秸秆/灰分和化学养分)的处理:秸秆不还田(CK)、秸秆还田(SR)和秸秆焚烧还田(SBR),探讨长期秸秆还田条件对南方双季稻田土壤有机碳组分及土壤酶活性的影响。结果表明,与CK相比,长期秸秆还田有利于提高早稻产量(P=0.057),并显著增加早晚稻田土壤的总有机碳(TOC)和微生物量碳(MBC)含量。而稻草焚烧还田对TOC无显著影响,但降低了早稻轻组有机碳(LFOC)和晚稻易氧化有机碳(EOC)含量,而显著增加了可溶性有机碳(DOC),且显著降低了土壤pH。我们研究还表明,长期秸秆还田条件下,MBC是评估双季稻系统土壤有机碳变化最敏感的指标;此外,SBR和SR对土壤酶活性的影响早晚稻稻田土壤呈现相反趋势,进而导致土壤有机碳组分含量存在季节差异,尤其是改变了土壤DOC含量,而早晚稻DOC与β-木糖苷酶均呈正相关。可见,秸秆还田较秸秆焚烧还田更有利于土壤有机碳组分的固持与提高,但其对晚稻土壤酶活性的负作用有待进一步研究。


Abstract:

Long-term straw return is an important carbon source for improving soil organic carbon (SOC) stocks in croplands, and straw removal through burning is also a common practice in open fields in South China.  However, the specific effects of long-term rice straw management on SOC fractions, the related enzyme activities and their relationships, and whether these effects differ between crop growing seasons remain unknown.  Three treatments with equal nitrogen, phosphorus, and potassium nutrient inputs, including straw/ash and chemical nutrients, were established to compare the effects of straw removal (CK), straw return (SR), and straw burned return (SBR).  Compared to CK, long-term SR tended to improve the yield of early season rice (P=0.057), and significantly increased total organic carbon (TOC) and microbial biomass carbon (MBC) in double-cropped rice paddies.  While SBR had no effect on TOC, it decreased light fraction organic carbon (LFOC) in early rice and easily oxidizable organic carbon (EOC) in late rice, significantly increased dissolved organic carbon (DOC), and significantly decreased soil pH.  These results showed that MBC was the most sensitive indicator for assessing changes of SOC in the double-cropped rice system due to long-term straw return.  In addition, the different effects on SOC fraction sizes between SR and SBR were attributed to the divergent trends in most of the soil enzyme activities in the early and late rice that mainly altered DOC, while DOC was positively affected by β-xylosidase in both early and late rice.  We concluded that straw return was superior to straw burned return for improving SOC fractions, but the negative effects on soil enzyme activities in late rice require further research.
 

Key words: double-cropped rice paddy system ,  straw return ,  straw burned return ,  SOC fractions ,  soil enzyme activities