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草业学报 ›› 2024, Vol. 33 ›› Issue (11): 15-29.DOI: 10.11686/cyxb2023485

• 研究论文 • 上一篇    下一篇

翻耕和植物残体覆盖对“黑土滩”型退化草地土壤氧化亚氮排放的影响

冯娅斯1,2(), 蒋文婷1,2, 刘益宏1,2, 王燕1,2, 李渊3, 陈有超1,2, 蔡延江1,2()   

  1. 1.浙江农林大学省部共建亚热带森林培育国家重点实验室,浙江 杭州 311300
    2.浙江农林大学环境与资源学院,碳中和学院,浙江 杭州 311300
    3.兰州大学草地农业科技学院,草种创新与草地农业生态系统全国重点实验室,甘肃庆阳草地农业生态系统国家野外科学观测研究站,甘肃 兰州 730020
  • 收稿日期:2023-12-18 修回日期:2024-03-18 出版日期:2024-11-20 发布日期:2024-09-09
  • 通讯作者: 蔡延江
  • 作者简介:E-mail: yjcai@zafu.edu.cn
    冯娅斯(1999-),女,四川广安人,在读硕士。E-mail: feng8143853184@163.com
  • 基金资助:
    国家自然科学基金面上项目(41877085);浙江农林大学校科研发展基金项目(2018FR005)

Effects of plowing and plant residue mulching on soil nitrous oxide emissions in a black soil beach-type degraded grassland

Ya-si FENG1,2(), Wen-ting JIANG1,2, Yi-hong LIU1,2, Yan WANG1,2, Yuan LI3, You-chao CHEN1,2, Yan-jiang CAI1,2()   

  1. 1.State Key Laboratory of Subtropical Silviculture,Zhejiang A&F University,Hangzhou 311300,China
    2.College of Environment and Resources,College of Carbon Neutrality,Zhejiang A&F University,Hangzhou 311300,China
    3.College of Pastoral Agriculture Science and Technology,The State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems,Lanzhou University,National Field Scientific Observation and Research Station of Grassland Agro-ecosystems in Gansu Qingyang,Lanzhou 730020,China
  • Received:2023-12-18 Revised:2024-03-18 Online:2024-11-20 Published:2024-09-09
  • Contact: Yan-jiang CAI

摘要:

草地修复是推动草地生态系统恢复和实现可持续发展的关键。为了探究翻耕和植物残体覆盖对极度退化高寒草地土壤氧化亚氮(N2O)排放的影响,以青藏高原东缘高寒草甸为研究对象,设置了移除草地地上和地下(0~20 cm)全部植物以模拟“黑土滩”型退化草地(CK)、退化草地进行翻耕(PL)、退化草地进行植物残体覆盖(MR)、退化草地进行翻耕和植物残体覆盖(PL+MR)4种处理,并测定不同处理下的土壤基础理化指标、微生物生物量、胞外酶活性、硝化和反硝化酶活性、功能微生物基因丰度和28 d N2O累积排放量。结果显示:翻耕较对照显著增加了土壤N2O累积排放量,增加了44.2%,翻耕后进行植物残体覆盖显著抑制了N2O排放,减少了29.1%。翻耕后,土壤pH、可溶性有机碳(DOC)和微生物生物量碳(MBC)含量、β-1,4-葡萄糖苷酶(BG)和β-1,4-N-乙酰氨基葡萄糖苷酶(NAG)活性、氨氧化古菌(AOA)和氨氧化细菌(AOB)amoA基因丰度显著增大,增幅分别为2.6%、209.5%、23.8%、180.4%、233.9%、74.6%和68.0%,土壤C/N、有机碳(SOC)和微生物生物量氮(MBN)含量显著降低,降幅分别为11.3%、13.6%和72.8%。翻耕后覆盖植物残体较翻耕显著降低了土壤DOC含量,抑制了BG、NAG、亮氨酸氨基肽酶(LAP)、酸性磷酸酶(AP)活性及AOA-amoA、AOB-amoAnosZ Ⅰ基因丰度,降幅分别为12.8%、49.1%、59.9%、31.6%、25.0%、46.5%、59.5%、23.1%,显著增加了MBN含量,增幅为29.1%。相关性分析表明,土壤N2O累积排放量与pH、DOC含量、胞外酶活性、氮循环基因丰度(除nirS以外)均呈显著正相关,而与C/N、SOC和MBN含量显著负相关。AOA-amoA和AOB-amoA丰度是影响N2O排放的关键因子。综上,翻耕会增加土壤胞外酶活性和amoA基因丰度,但会导致SOC分解消耗和N2O增排,而植物残体覆盖能够有效缓解这些负面影响,是一种可行的改良措施。

关键词: 翻耕, 植物残体覆盖, 高寒草甸, 氮循环功能基因, 土壤氧化亚氮排放

Abstract:

Grassland restoration is the key measure to promote the restoration of the grassland ecosystem and achieve sustainable development. The aim of this work was to explore the effects of plowing and mulching with plant residues on soil nitrous oxide (N2O) emissions from an extremely degraded alpine grassland. The experiment was conducted in an alpine meadow in Hongyuan County, Sichuan, China, on the Eastern edge of the Qinghai-Tibetan Plateau. The experiment consisted of a control (CK) and three treatments; i.e., black soil beach-type degraded grassland with roots removed from the 0-20 cm soil layer and no plant residues (CK), plowed degraded grassland (PL), degraded grassland mulched with plant residues (MR), and plowed degraded grassland mulched with plant residues (PL+MR). We measured soil basic physical and chemical indicators, microbial biomass, extracellular enzyme activity, nitrification enzyme activity, denitrification enzyme activity, functional microbial gene abundance, and 28-day cumulative N2O emissions. The results showed that, compared with CK, PL significantly increased cumulative soil N2O emissions (by 44.2%). Soil N2O emissions were significantly lower in PL+MR (by 29.1%) than in PL. Compared with CK, PL significantly enhanced soil pH (by 2.6%), increased dissolved organic carbon (DOC) and microbial biomass carbon (MBC) concentrations (by 209.5% and 23.8%, respectively), increased activities of β-1,4-glucosidase (BG) and β-1,4-N-acetylglucosaminidase (NAG) (by 180.4% and 233.9%, respectively), and increased abundance of amoA genes of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) (by 74.6% and 68.0%, respectively). Compared with CK, PL significantly decreased soil C/N (by 11.3%), decreased soil organic carbon (SOC) and microbial biomass nitrogen (MBN) concentrations (by 13.6% and 72.8%, respectively). Compared with PL, PL+MR significantly decreased soil DOC concentration (by 12.8%), significantly reduced BG, NAG, leucine aminopeptidase (LAP) and acid phosphatase (AP) activities (by 49.1%, 59.9%, 31.6%, and 25.0%, respectively), and decreased AOA-amoA, AOB-amoA, and nosZ I genes abundance (by 46.5%, 59.5%, and 23.1%, respectively). Compared with PL, PL+MR significantly increased MBN concentration (by 29.1%). Correlation analyses showed that cumulative soil N2O emissions were significantly positively correlated with the pH, DOC concentration, extracellular enzyme activity, and abundance of genes related to the nitrogen cycling (except nirS), and significantly negatively correlated with C/N, SOC and MBN concentrations. The abundance of AOA-amoA and AOB-amoA were the key factors affecting N2O emissions. In summary, plowing resulted in enhanced soil extracellular enzyme activity and amoA gene abundance, as well as increased SOC decomposition and consumption and N2O emissions. Mulching with plant residues effectively alleviated these negative effects, indicating that it is a feasible improvement measure.

Key words: plowing, plant residue mulching, alpine meadow, nitrogen cycle functional genes, soil nitrous oxide emission