不同温度条件下生物质炭陈化对华南集约化菜地土壤反硝化过程的影响  

Effects of field-aged biochar on denitrification of vegetable soils under different temperature conditions in south China

作　　者：刘一戈 胡家帅 王朝 彭子倩 郝珖存 卢瑛[1] 李博 LIU Yi-ge;HU Jia-shuai;WANG Chao;PENG Zi-qian;HAO Guang-cun;LU Ying;LI Bo(College of Natural Resources and Environment,South China Agricultural University,Guangdong,Guangzhou 510642;CCCC Fourth Harbor Engineering Institute Co.,Ltd,Guangzhou,Guangdong 510230,China)

机构地区：[1]华南农业大学资源环境学院,广东广州510642 [2]中交四航工程研究院有限公司,广东广州510230

出　　处：《植物营养与肥料学报》2022年第9期1641-1651,共11页Journal of Plant Nutrition and Fertilizers

基　　金：国家自然科学基金项目(41807021,32001142)。

摘　　要：【目的】比较不同温度下新鲜生物质炭与陈化生物质炭对华南集约化菜地土壤N_(2)O排放的影响,以深化对生物质炭减排机理的认识。【方法】本研究采用乙炔抑制法进行室内培养试验,共设置3个温度梯度(10℃、20℃和30℃)和3个生物质炭处理:无生物质炭(CK)、新鲜生物质炭(FB)以及田间陈化生物质炭(FAB),共9个处理。同时,各处理分别设置不加乙炔和添加10%体积含量乙炔的平行处理,以测定N_(2)O排放量并作差计算N_(2)排放量。对不含乙炔处理则测定土壤pH、电导率(EC)、可溶性有机碳(DOC)、NO_(3)^(-)、NH-4~+、NO_(2)^(-)含量,以及土壤中反硝化功能基因nirS、nirK、nosZ和nosZⅡ的丰度。【结果】温度升高显著增加了菜地土壤N_(2)O和N_(2)的排放量,显著提高了土壤pH和土壤NH_(4)^(+)含量,并明显降低了DOC和NO_(3)^(-)含量(P<0.01),但是并未明显影响反硝化过程的功能基因nirK、nirS、nosZ和nosZⅡ的丰度。FB、FAB在30℃时分别显著降低了菜地土壤N_(2)O排放量的18.8%、22.3%,并且显著降低了反硝化总脱氮量(N_(2)O+N_(2))(P<0.001)。FAB处理在30℃下能显著增加土壤中nirK和nosZⅡ基因丰度(P<0.05)。冗余分析显示,土壤pH、NO-2、DOC是影响反硝化功能基因的主要因素,以pH贡献率最高。逐步回归分析表明,N_(2)O排放量在CK处理中主要受土壤DOC含量影响,在FB处理中主要受土壤NO_(3)^(-)含量影响,在FAB处理中则受到土壤NO_(3)^(-)和NO_(2)^(-)含量影响。【结论】升温对菜地土壤N_(2)O排放的影响呈非线性增长,以10℃增至20℃时增幅最大。在反硝化过程中,新鲜生物质炭通过持留NO_(3)^(-)以减少其参与反硝化过程,进而减少N_(2)O排放量。陈化生物质炭则通过影响反硝化过程的底物NO_(3)^(-)、NO_(2)^(-)含量及反硝化功能基因nirK和nosZⅡ的丰度,从而导致土壤氮以NO或N_(2)形式损失,减少N_(2)O的排放量。低温抑制微生物的活性,因此,【Objectives】In order to improve the understanding of how biochar reduces N_(2)O emissions,we compared the effects of fresh and aged biochar at different temperatures on N_(2)O emissions from intensive vegetable soils in southern China.【Methods】An incubation experiment was conducted,and the treatments were soil without biochar addition control(CK),addition of fresh biochar(FB),and addition of field-aged biochar(FAB)at 10℃,20℃,and 30℃.A parallel treatment was set up for each treatment with and without the addition of 10%volume content of acetylene to measure the N_(2)O emission,and the difference was made to obtain N_(2) emissions.For the treatments without acetylene addition,soil pH,electrical conductivity(EC),dissolved organic carbon(DOC),NO_(3)^(-),NH_(4)^(+),and NO_(2)^(-)nosZⅡ)were measured.【Results】The elevation of incubation temperature significantly increased N_(2)O and N_(2) emissions,increased soil pH and NH_(4)^(+)-N content,decreased soil DOC and NO_(3)^(-)-N contents(P<0.01),but did not affect the abundance of nirK,nirS,nosZ and nosZⅡ.FB and FAB treatments significantly reduced N_(2)O emissions by 18.8%and 22.3%at 30℃respectively and the total denitrifying nitrogen amount(N_(2)O+N_(2))(P<0.01).FAB significantly increased the nirK and nosZⅡgene abundance at 30℃(P<0.05).The redundancy analysis showed that soil pH,NO_(2)^(-) and DOC were the main factors affecting denitrification function genes,among which pH was the most important factor.Stepwise regression analysis showed that N_(2)O emission was mainly affected by DOC content in CK treatment,N_(2)O emissions in the FB treatment were mainly influenced by soil NO_(3)^(-) content,and N_(2)O emissions in the FAB treatment were influenced by soil NO_(3)^(-) and NO_(2)^(-) content.【Conclusions】N_(2)O emissions increased with temperature nonlinearly,and the greatest increment occurred from 10℃to 20℃.Fresh biochar enhanced soil pH and retain NO_(3)^(-) emission.FAB decreased soil NO_(3)^(-) and NO_(2)^(-)or N_(2),not in form

关 键 词：温度升高 集约化菜地 生物质炭陈化 二氧化氮 反硝化 

分 类 号：S154.1[农业科学—土壤学]