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选取内蒙古河套灌区3种不同盐渍化程度土壤(盐土、重度盐渍化土壤和轻度盐渍化土壤),采用室内培养方法,用不同浓度KCl溶液调节不同盐渍化程度土壤盐含量分别为原土壤盐含量(对照)的2倍和3倍,研究盐分对不同盐渍化程度土壤氧化亚氮(N_2O)排放的影响.结果表明,盐分含量显著影响不同盐渍化程度土壤N_2O排放.无外源盐分加入时,不同盐碱程度土壤中盐土N_2O排放量最高,重度盐渍化土壤次之,轻度盐渍化土壤最低.外源盐加入后,随盐度梯度升高,与其对照相比,盐土N_2O排放量降低;重度盐渍化土壤N_2O排放量呈现先增加后降低趋势;轻度盐渍化土壤N_2O排放量升高.与其对照相比,土壤的盐分含量增加2倍时,盐土N_2O排放量减少90%;轻度盐渍化土壤N_2O排放量增加9倍.外源盐加入不同盐渍化程度土壤对N_2O排放的影响程度取决于土壤培养前后铵态氮含量差值,加入外源盐后,N_2O累积排放变化量的94.6%由土壤NH_4~+-N含量差值解释(R2=0.95,p<0.01).
Three kinds of soil with different salinization levels (saline soil, heavily salinized soil and lightly salinized soil) were selected from Hetao Irrigation District in Inner Mongolia. The soil salt content under different salinization degrees was adjusted by indoor culture method with KCl solution of different concentrations as The results showed that the salt content significantly affected the N 2 O emission of soils with different salinization degree. The results showed that salinity had a significant effect on the N 2 O emission of soil with different salinization degree. When exogenous salinity was added, N2O emission of saline soil was the highest in different saline-alkali soil levels, followed by severe salinization soil and lowest in salinized soil. After addition of exogenous salt, with the increase of salinity gradient, N 2 O emission of salinized soil decreased, N 2 O emission of salinized soil increased first and then decreased, and N 2 O emission of slightly salinized soil increased.Compared with the control, soil salt content increased by 2 times, N 2 O 3 emission decreased by 90%, N 2 O emission in mild salinized soil increased by 9 times.Effects of exogenous salt added to different salinization degree on soil N 2 O emission degree depends on the difference of ammonium nitrogen content before and after soil culture After the source salt, N. 94.6% of the cumulative emission change of _2O was explained by the difference of NH_4 ~ + -N content (R2 = 0.95, p <0.01).