氮素调控对冻融过程中土壤N_2O排放的影响  

Effects of Nitrogen Application on N_2O Flux from Fluvo-aquic Soil Subject to Freezing and Thawing Process

作　　者：王风[1] 白丽静[1] 张克强[1] 黄治平[1] 杨鹏[1] 张金凤[1] 

机构地区：[1]农业部环境保护科研监测所,天津300191

出　　处：《环境科学》2009年第11期3142-3145,共4页Environmental Science

基　　金："十一五"国家科技支撑计划项目(2006BAD17B02);公益性科研院所基本科研业务专项;农业部"948"项目(2008-Z10)

摘　　要：应用室内冰柜模拟冻融过程,研究了不同氮素形态(铵态氮、硝态氮和酰胺态氮)和浓度(40、200和800 mg/L)对潮土N2O排放通量的影响.结果表明,随土壤冻结时间的延长N2O排放通量缓慢降低,土壤融化初期出现一个土壤N2O排放通量高峰,而后随土壤逐渐融化的进行N2O排放通量缓慢升高.3种氮素浓度条件下,铵态氮、硝态氮和酰胺态氮冻融过程中土壤平均N2O排放通量分别为119.01、205.28、693.95μg.(m2.h)-1,611.61、1 084.40、1 820.02μg.(m2.h)-1和148.22、106.13、49.74μg.(m2.h)-1,而对照处理仅为100.35μg.(m2.h)-1.随氮素浓度的增加,铵态氮、硝态氮源土壤N2O累积排放通量分别比对照增加17.49%、40.09%、425.67%和563.38%、915.28%、1458.6%,且施加的浓度越高累积排放量越大,但达到稳定N2O排放通量的时间向后推移.随浓度增加酰胺态氮处理土壤N2O排放通量随浓度增加而降低.建议潮土越冬水中铵态氮和硝态氮浓度应分别小于200 mg/L和40 mg/L,酰胺态氮的浓度不限,从而减少土壤N2O的排放.The experiment was conducted to investigate the effects of different forms of nitrogen application （ammonium, NH4＋-N; nitrate, NO3- -N; and amide-N, NH2-N） and different concentrations（40, 200 and 800 nag/L） on N20 flux from the fluvo-aquic soil in a lab-simulated freezing and thawing process. N2O flux slowly decreased with soil freezing, and then increased slowly with soil thawing, reaching a peak at the initial thawing stage. The average NzO fluxes with addition of NH4＋ -N, NO3--N and NH2-N are 119.01, 611.61 and 148.22μg· （m2·h）^-1 respectively at the concentration of 40 mg/L; 205.28, 1 084.40 and 106.13μg· （m2·h）^-1 at the concentration of 200 mg/L; 693.95, 1 820.02 and 49.74μg· （m2·h）^-1 at the concentration of 800 mg/L. The control is only 100.35 μg· （m2·h）^-1. N20 flux with addition of NH4 -N and NO3- -N increased with increasing concentration, ranging from 17.49% to 425.67% for NH4＋ -N, and 563.38% to 1 458.6% for NO3--N compared with control. There was a time lag achieving stable N20 emission flux with concentration increase. In contrast, by adding NH2-N to soil, N20 flux decreased with increasing concentration. In sum, inorganic nitrogen such as NH4＋ -N or NO3- -N fertilizer incorporated in soil enhanced the cumulative N2O flux from the fluvo-aquic soil relative to amide-N. This study suggested that ammonium and nitrate concentration in overwintering water should be less than 200 mg/L and 40 mg/L in order to reduce N2O emissions from soil, regardless of amide-N.

关 键 词：冻融过程 铵态氮 硝态氮 酰胺态氮 N2O排放通量 

分 类 号：X144[环境科学与工程—环境科学] S154[农业科学—土壤学]