设施菜田土壤N_2O产生对O_2的响应  

Nitrous Oxide Production in Response to Oxygen in a Solar Greenhouse Vegetable Soil

作　　者：陈吉吉 宋贺[2] 曹文超[1] 王乙然 王敬国[1] CHEN Ji-ji;SONG He;CAO Wen-chao;WANG Yi-ran;WANG Jing-guo(College of Resource and Environment,China Agrieuhure University,Beijing 100193,China;College of Agronomy,Anhui Agricultural University,Hefei 230036,China)

机构地区：[1]中国农业大学资源与环境学院,北京100193 [2]安徽农业大学农学院,合肥230036

出　　处：《环境科学》2018年第8期3826-3834,共9页Environmental Science

基　　金：国家自然科学基金项目(41230856)

摘　　要：以添加(DIS)/不添加(DI)玉米秸秆的常规设施菜田土壤为研究对象,通过室内培养试验,利用在线自动监测培养系统,在不同初始氧气体积分数下(0%、1%、3%、5%和10%)监测土壤N_2O、NO、N_2和CO_2产生量的动态变化,并同步分析了土壤无机氮(NO-2、NO-3、NH+4)含量,同时设置添加Na Cl O3的处理抑制土壤NO-2的氧化,以期对比研究不同碳投入菜田土壤N_2O产生量对O_2的响应.结果表明,厌氧条件下土壤N_2O产生量显著高于有氧条件下土壤N_2O产生量(P<0.01).当氧气体积分数≤1%时,添加秸秆的(DIS)土壤N_2O产生量显著高于未添加秸秆的(DI)土壤(P<0.01).土壤中氧耗竭时会观察到明显的N_2O产生速率峰值,但N_2产生速率峰值随着初始氧气体积分数的升高极显著降低(P<0.01),反之,土壤中如果没有出现氧耗竭的现象,则N_2O和N_2产生量随着初始氧气体积分数的升高显著降低(P<0.01).初始氧气体积分数介于1%~5%时,培养过程中会观察到持续的NO-2累积,且在该氧梯度内N_2O/(NO+N_2O+N_2)指数显著高于0%以及10%初始氧气体积分数的处理,此外,添加Na Cl O3后,当初始氧气体积分数为5%和10%时,持续增加的NO-2与N_2O产生量两者之间线性相关(R2≥0.85).本研究结果表明,低氧条件下不完全的反硝化和NO-2诱导的硝化细菌反硝化共同作用,显著增加了土壤N_2O的产生量和N_2O/(N_2O+NO+N_2)指数;但是,有氧条件下土壤N_2O的产生量显著低于厌氧条件(P<0.01).To explore the sources of peak nitrous oxide （N2O ） flushes in solar greenhouse vegetable field, an experiment was conducted with two conventional vegetable soils under different initial volume fractions of oxygen （O2 ） （0% , 1% , 3% , 5% , and 10% ）. A robotized incubation system was employed to analyze the gas kinetics [ O2 , N2 O, nitric oxide （NO） , nitrogen （ N2 ） , and carbon dioxide （CO2 ） ] every 6 or 8 h and calculate the N2O/（ NO ＋ N2O ＋ N2 ） index. Sodium chlorate （NaClO3 ） was used to inhibit the oxidation of NO2 to further explore the relationship between N2O and nitrite （ NO2 ）. A parallel off-line incubation in triplicates was conducted under similar conditions to measure the dynamic changes in inorganic nitrogen content [ ammonia （ NH4＋ ） , nitrate （NO3 ） , and NO2 ]. The results showed that N2O production under anaerobic condition was significantly higher than that under aerobic condition. The peak value of N2 O in the soil collected from a straw-added plot （DIS） was significantly higher than that in the soil from non-straw added plot （DI） （P 〈 0. 01 ） when the volume fraction of oxygen was ≤1%. Oxygen can directly affect N2O production by delaying or inhibiting N： 0 reduction, with significant increase in N2O production rate under oxygen-depleted condition. However, the N：production rate decreased significantly with increase in initial oxygen volume fraction （P 〈 0.01 ）. When the initial volume fraction of oxygen was between 1% and 5% , a continuous accumulation of NO2 was observed during the incubation period, resulting in the significantly higher N2O/（ NO ＋ N2O ＋ N2 ） index than that in either anaerobic or 10% of oxygen treatments. Furthermore, a linear correlation was observed between NO2- and N2O at 5% and 10% of oxygen with the addition of NaC103 （ R2≥ 0. 85）. Incomplete denitrification and nitrifier denitrification from NO2- induction co-occurred in the range of 1% and 5% volume fractions of oxygen, s

关 键 词：氧 N2O 反硝化 硝化细菌反硝化 亚硝酸盐 N2O/(N2O+NO+N2)指数 

分 类 号：X144[环境科学与工程—环境科学]