椰糠生物炭对热区双季稻田N_(2)O和CH_(4)排放的影响  

Effects of Coconut Chaff Biochar Amendment on Methane and Nitrous Oxide Emissions from Paddy Fields in Hot Areas

作　　者：王紫君 王鸿浩 李金秋 伍延正 符佩娇 孟磊[1] 汤水荣 WANG Zi-jun;WANG Hong-hao;LI Jin-qiu;WU Yan-zheng;FU Pei-jiao;MENG Lei;TANG Shui-rong(College of Tropical Crops,Hainan University,Haikou 570228,China)

机构地区：[1]海南大学热带作物学院,海口570228

出　　处：《环境科学》2021年第8期3931-3942,共12页Environmental Science

基　　金：海南省自然科学基金高层次人才项目(2019RC049);国家自然科学基金项目(41661051,42067008)。

摘　　要：基于稻菜轮作模式,选择海南双季稻田为对象进行氧化亚氮(N_(2)O)和甲烷(CH_(4))排放的原位监测,探究椰糠生物炭对该系统稻田温室气体排放的影响.试验设当地常规施肥对照(CON)、氮肥配施20 t·hm^(-2)生物炭(B1)、氮肥配施40 t·hm^(-2)生物炭(B2)及不施氮对照(CK) 4个处理,采用静态箱-气相色谱法监测整个水稻种植季稻田N_(2)O和CH_(4)排放,并估算增温潜势(GWP)和温室气体排放强度(GHGI).结果表明,早稻季N_(2)O排放动态与土壤矿质氮含量密切相关,排放集中在水稻苗期与分蘖期施肥后,各处理早稻季N_(2)O累积排放量为0.18~0.76 kg·hm^(-2),相较于CON处理,生物炭处理减排18%~43%,其中B2处理达显著水平;生物炭可能通过促进N_(2)O的还原减少早稻苗期N_(2)O排放;提高土壤硝态氮含量而增加了早稻分蘖期N_(2)O排放.晚稻季N_(2)O排放集中在抽穗期和成熟期,累积排放量为0.17~0.34 kg·hm^(-2),B1处理减排37%,B2增加3%,差异均不显著.稻田CH_(4)排放高峰出现在早稻季后期与晚稻季前期.各处理早稻季CH_(4)累积排放量为3.11~14.87 kg·hm^(-2),CK较CON处理增排39%,生物炭处理可能提高土壤通气性限制早稻季产CH_(4)能力,B1和B2处理分别较CON减排28%和71%;晚稻季CH_(4)累积排放量为53.1~146.3 kg·hm^(-2),排放动态与NH4+-N含量极显著正相关,CK和B1分别较CON处理增加52%和99%,B2处理显著增加176%CH_(4)排放.早稻季B1和B2处理较CON分别增产12.0%和14.3%,晚稻季分别增产7.6%和0.4%.由于晚稻季甲烷排放的增加,施用生物炭增加了双季稻田总增温潜势(GWP),其中高量生物炭达显著水平;不同施用量生物炭对双季稻田温室气体排放强度(GHGI)无显著影响.椰糠生物炭在热区稻田温室气体减排方面的应用仍需进一步研究.Based on the rice-vegetable crop rotation model,in-situ measurements of nitrous oxide (N_(2)O) and methane (CH_(4))emissions were conducted in double-cropping rice fields in Hainan to determine the impact of coconut chaff biochar on greenhouse gas emissions.The experiment involved four treatments:conventional farming fertilization (CON),nitrogen fertilizer combined with 20t·hm^(-2)biochar (B1),nitrogen fertilizer combined with 40 t·hm^(-2)biochar (B2),and no nitrogen fertilizer,as the control (CK).The N_(2)O and CH_(4) emissions were measured using static chamber-gas chromatography during the two paddy seasons,and the global warming potential (GWP) and greenhouse gas intensity (GHGI) were also estimated.The results show that N_(2)O emission dynamics during the early rice season are closely related to the mineral nitrogen content of the soil.The N_(2)O is emitted at the rice seedling and tillering stages after fertilization.The cumulative N_(2)O emission during the early rice season was 0.18-0.76 kg·hm^(-2).Compared with the CON treatment,the biochar treatments reduced N_(2)O by 18%-43%,and the B2 treatment resulted in a significant reduction.The addition of biochar may promote the reduction of N_(2)O at the early rice seedling stage and increase N_(2)O emissions by improving the soil NO3--N content at the early rice tillering stage.During the late rice season,N_(2)O is emitted during the heading and maturity stages,and the cumulative N_(2)O emission was 0.17-0.34 kg·hm^(-2).The B1 treatment reduced emissions by 37%,and B2 increased emission by only 3%,which is not a significant difference.The peak of CH_(4)emissions from rice fields appeared in the late phase of the early rice season and prophase of the late rice season.The cumulative emission of CH_(4)in the early rice season was 3.11-14.87 kg·hm^(-2).Compared with CON,the CK treatment increased emission by 39%.The biochar treatment may increase soil aeration and limit the ability of CH_(4) production in the early rice season,as B1 and B2 treatments reduced

关 键 词：椰糠 生物炭 热区 双季稻田 温室气体 增温潜势(GWP) 

分 类 号：X16[环境科学与工程—环境科学]