中国农业科学 ›› 2022, Vol. 55 ›› Issue (4): 743-754.doi: 10.3864/j.issn.0578-1752.2022.04.010

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

紫云英与油菜混播对稻田土壤N2O排放及相关功能基因丰度的影响

杨滨娟(),李萍,胡启良,黄国勤()   

  1. 江西农业大学农学院/江西农业大学生态科学研究中心,南昌 330045
  • 收稿日期:2021-01-21 接受日期:2021-05-14 出版日期:2022-02-16 发布日期:2022-02-23
  • 通讯作者: 黄国勤
  • 作者简介:杨滨娟,Tel:0791-83828143;E-mail:yangbinjuan@jxau.edu.cn
  • 基金资助:
    国家自然科学基金项目(32160528);国家重点研发计划课题(2016YFD0300208);国家自然科学基金(41661070)

Effects of the Mixted-cropping of Chinese Milk Vetch and Rape on Soil Nitrous Oxide Emission and Abundance of Related Functional Genes in Paddy Fields

YANG BinJuan(),LI Ping,HU QiLiang,HUANG GuoQin()   

  1. College of Agronomy, Jiangxi Agricultural University/Research Center on Ecological Science Jiangxi Agricultural University, Nanchang 330045
  • Received:2021-01-21 Accepted:2021-05-14 Online:2022-02-16 Published:2022-02-23
  • Contact: GuoQin HUANG

摘要:

【目的】探究绿肥混播对稻田土壤N2O的减排效果和机制,筛选既高产稳产,又减排的适合南方双季稻区发展应用的绿肥混播种植模式。【方法】比较不同紫云英与油菜混播比例(单播紫云英(CK1)、单播油菜(CK2))、3/4紫云英+1/4油菜(3/4M + 1/4R)、1/2紫云英+1/2油菜(1/2M + 1/2R)、1/4紫云英+3/4油菜(1/4M + 3/4R))对稻田N2O排放规律及相关功能基因的影响。【结果】(1)作物种类影响N2O排放。各处理的N2O排放规律基本一致,其中冬作季N2O排放主要集中在冬季绿肥的盛花期,早晚稻季主要集中在水稻的分蘖、灌浆和成熟期。总体来看,稻田N2O排放主要集中在水稻季,早稻季的N2O排放量低于晚稻季;2018年稻田N2O排放通量总体比2019年高。(2)各处理的早稻N2O累积排放量差异均不显著。连续两年单播处理的N2O累积排放量低于混播各处理,其中2019年处理CK1最低,处理3/4M+1/4R的N2O周年累积排放量在各混播处理中最低。(3)整体来看,晚稻土壤的amoA-AOA和amoA-AOB基因拷贝数比早稻要高,amoA-AOA基因拷贝数比amoA-AOB高1—2个数量级。晚稻的土壤nirSnirKnosZ基因拷贝数比早稻要高,其中nirS基因拷贝数比nirKnosZ高1—2个数量级。紫云英与油菜混播提高了土壤amoA-AOA和amoA-AOB基因丰度,amoA-AOA基因为优势功能基因,而且提高了土壤nirSnirKnosZ基因丰度,nirS基因占主导地位。反硝化基因拷贝数比硝化基因拷贝数高1—3个数量级,反硝化作用对N2O排放贡献更大。【结论】“3/4紫云英+1/4油菜-早稻-晚稻”种植模式在保证高产和高肥力的情况下,N2O排放量相对较低,是较理想的种植模式。

关键词: 紫云英, 油菜, 绿肥混播, 氧化亚氮, 功能基因, 稻田

Abstract:

【Objective】The aim of this study was to determine how a green manure mixted-cropping affected nitrous oxide (N2O) emissions from soil and the abundance of related functional genes in paddy field soil. The ultimate aim of this research was to identify a green manure mixted-cropping that had high and stable yields and reduces emissions, and was suitable for cultivation in the double-rice areas of southern China. 【Method】The effects of mixted-cropping of Chinese milk vetch and rape at different ratios (single Chinese milk vetch, single rape, 3/4 Chinese milk vetch +1/4 rape, 1/2 Chinese milk vetch +1/2 rape, and 1/4 Chinese milk vetch +3/4 rape) on N2O emissions and the abundance of related functional genes in paddy field soil were determined and compared. 【Result】(1) The crop species affected N2O emissions. The N2O emissions were similar among the different treatments. Among them the N2O emissions from winter crop soil were mainly concentrated at its flowering stage, and those during the rice growing period were concentrated at the tillering, filling, and maturity stages of early and late rice crops. On the whole, the N2O emissions from paddy fields were lower N2O in the early rice season than that in the late rice season. The overall N2O emissions flux in the paddy fields was higher in 2018 than that in 2019. (2) There was no significant difference in N2O cumulative emission of early rice under different treatments. The cumulative N2O emissions from a single seeding treatment were lower than those from mixed treatments over two consecutive years. The annual cumulative N2O emissions were lowest under CK1 in 2019. Among all the mixed treatments, the 3/4 Chinese milk vetch +1/4 rape treatment had the lowest annual cumulative N2O emissions. (3) In general, the copy number of amoA-AOA and amoA-AOB genes was higher in the soil of late rice than that in the soil of early rice, and the copy number of AmoA-AOA was up to two orders of magnitude higher in late rice soil than in early rice soil. The copy numbers of nirS, nirK and nosZ were higher in the soil of late rice crops than that in the soil of early rice crops, and the copy number of nirS was up to two orders of magnitude higher than those of nirK and nosZ in late rice soil. The mixted-cropping of Chinese milk vetch and rape increased the abundance amoA-AOA and amoA-AOB genes in soil, and amoA-AOA was the dominant functional gene. It also increased the abundance of nirS, nirK and nosZ genes in soil, and nirS gene was the dominant gene. The copy number of genes related to denitrification was one to three orders of magnitude higher than the copy number of genes related to nitrification, indicating that denitrification made a larger contribution to N2O emissions. 【Conclusion】Overall, the 3/4 Chinese milk vetch + 1/4 rape-early rice-late rice was the best mixed planting system, because it had the best combination of low N2O emissions as well as high yield and high fertility.

Key words: Chinese milk vetch, rape, green manure mixted-cropping, nitrous oxide, functional gene, paddy fields