生物炭介导的不同地表条件下土壤N_2O的排放特征  

Characteristics of Biochar-mediated N_2O Emissions from Soils of Different Surface Conditions

作　　者：邹娟[1] 胡学玉[1] 张阳阳[1] 张迪[1] 陈威[1] 王向前[1] 陈窈君 刘扬[1] 

机构地区：[1]中国地质大学(武汉)环境学院,武汉430074

出　　处：《环境科学》2017年第5期2093-2101,共9页Environmental Science

基　　金：国家自然科学基金项目(41371485;41071159);湖北省自然科学基金项目(2014CFA116)

摘　　要：为探究不同地表条件下农田土壤N_2O产生与释放对生物炭输入的响应,于2014~2015年小麦-玉米生长季,采用田间小区试验的方法,在不同生物炭用量[0 t·(hm^2·a)-1(CK)、5 t·(hm^2·a)-1(BC5)、45 t·(hm^2·a)-1(BC45)]及不同地表条件下[种植作物(以+表示)、裸地(以-表示)],对土壤N_2O释放、土壤铵态氮(NH_4^+-N)和硝态氮(NO_3^--N)的动态变化进行了观测分析.结果表明:(1)在小麦生长季,CK+、BC5+、BC45+这3个处理的土壤N_2O排放通量分别在21.70~88.91、21.42~130.09、64.44~179.58μg·(m^2·h)-1之间变动,BC45+处理显著高于其它2个处理(P<0.05).其中在小麦生长盛期(返青拔节期-孕穗抽穗期),3个处理的土壤N_2O排放通量均较小麦越冬期显著下降(P<0.05),而且BC45+处理基于CK+、BC5+的土壤N_2O排放通量增幅在小麦孕穗抽穗期已较其越冬期时分别降低了18.43%、14.62%.在玉米生长季前期,BC45+处理的土壤N_2O排放通量也显著高于BC5+和CK+处理(P<0.05),但至玉米的抽穗期及成熟期,BC45+处理的土壤N_2O排放通量已与BC5+和CK+无显著差异.这说明随作物生长盛期的到来及地表覆盖度的增加,生物炭介导的土壤N_2O排放的增加效应得以有效抑制.同期裸地条件下相同生物炭处理的土壤N_2O排放通量结果也证实了这一点.(2)在小麦生长季及其同期的裸地条件下,与CK相比,两种生物炭处理均可增加土壤NO_3^--N和NH_4^+-N含量,但在作物生育盛期,BC5+、BC45+处理的两种氮素形态较CK+处理均有下降,尤以BC45+最为突出,其土壤NO_3^--N和NH_4^+-N含量分别下降了96.44%、69.40%.玉米生长季与小麦季有着相近的趋势.较高生物炭施用量土壤NH_4^+-N和NO_3^--N含量在作物生育盛期的明显下降与同期土壤N_2O的排放显著减少相呼应.因作物生长发育对氮元素吸收增加致呼吸底物减少可能是生物炭介导下N_2O排放减少的原因之一.(3)在小麦生长季,生物炭施用提高土壤pH从4.62�It was aimed to investigate the response to biochar addition on N2O gas production and emission in different surface conditions. To study the dynamic changes of soil N2O release, soil nitrate（NO3^--N） and ammonium（NH4^＋-N）, a field trials experiment was conducted from 2014 to 2015 in wheat and corn season, which contained three treatments[the blank control group （CK）, biochar applied at 5 t·（hm^2·a）^-1（BC5） and 45 t·（hm^2·a）^-1（BC45）, respectively] under crop cultivation（＋） and non-cultivation（-） condition. The results indicated that：1 During the season of wheat growth, the soil N2O emissions of CK＋, BC5＋, BC45＋ were 21.70-88.91, 21.42-130.09, 64.44-179.58 μg·（m2·h）^-1 respectively, and that of BC45＋ possessed a higher value than those of the other treatments（P〈0.05）. Compared with wheat winter period, the soil N2O emissions of the three treatments decreased evidently in wheat peak stage（returning green and jointing stage, booting and heading stage） （P〈0.05）, and the amplification of BC45＋ reduced by 18.43% and 14.62% in comparison with CK＋ and BC5＋ in wheat booting and heading stages. In the early stage of maize growth, the soil N2O emissions of BC45＋ were significantly increased compared with CK＋ and BC5＋（P〈0.05）. However, there were no significant differences among treatments of maize heading stage and mature stage. It showed that the biochar-mediated promotion effect of soil N2O emissions was effectively inhibited by crop growth and the increase of surface mulch. Besides, the result of soil N2O release in the same treatment had also confirmed this conclusion in bare land. 2 Under the conditions of wheat cultivation and homochronous non-cultivation, the soil NO3^--N and NH4^＋-N contents of BC5＋ and BC45＋ treatments were raised with respect to CK＋, but the values dropped significantly in wheat peak stage, especially for BC45＋ treatment, with 96.44% and 69.40% decrease respectively. The soil inorganic nitroge

关 键 词：生物炭 N2O 硝态氮 铵态氮 地表覆盖 

分 类 号：X144[环境科学与工程—环境科学]