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为研究臭氧浓度升高对农田土壤呼吸、硝化和反硝化作用的影响,采用开顶箱(OTC)法设置3个臭氧浓度处理,分别为对照CK、T1(100 nL.L-1臭氧)和T2(150 nL.L-1臭氧).以便携式土壤CO2通量观测仪测定不同臭氧浓度处理下的冬小麦田土壤呼吸速率,并采用气压过程分离(BaPS)法测定不同处理的土壤CO2产生速率、硝化速率和反硝化速率.结果表明,在本实验阶段内,CK、T1、T2处理的土壤呼吸速率之间无显著差异(p>0.05),其平均土壤呼吸速率分别为(5.36±0.72)、(5.08±0.04)、(4.94±0.18)μmol.(m2.s)-1.CK和T2处理的硝化速率和反硝化速率也均无显著差异(p>0.05).不同臭氧浓度处理下的土壤呼吸速率与土壤温度的指数回归关系均达显著水平(p<0.05),CK、T1和T2处理的土壤呼吸的Q10值分别为1.72、1.58和1.51.Pearson相关分析结果表明,CK处理中土壤硝化速率与反硝化速率和土壤含水量之间均存在显著相关关系(p<0.05),其相关系数分别为0.828和0.890;T2处理中硝化速率与土壤含水量之间存在显著相关关系(p<0.05),其相关系数为0.772.本研究表明,臭氧浓度升高未显著改变冬小麦田土壤呼吸、硝化和反硝化速率,但臭氧浓度升高显著降低了土壤呼吸的温度敏感性.
In order to study the effect of elevated ozone on soil respiration, nitrification and denitrification in farmland, three ozone concentrations were set by open top box (OTC), which were CK, T1 (100 nL.L-1 ozone) and T2 (150 nL.L-1 ozone). The soil respiration rate of winter wheat field under different ozone concentrations was measured by portable soil CO2 flux observer, and the soil CO2 production rate was measured by atmospheric pressure process separation (BaPS) Nitrification rate and denitrification rate.The results showed that there was no significant difference (P> 0.05) between the soil respiration rates of CK, T1 and T2 in the experimental stage, and the average soil respiration rates were (5.36 ± 0.72), (5.08 ± 0.04), (4.94 ± 0.18) μmol. (M2.s) -1. There was no significant difference in nitrification rate and denitrification rate between CK and T2 treatments (p> 0.05). Soil under different ozone concentrations The relationship between respiration rate and soil temperature was significant (p <0.05), and Q10 values of soil respiration under CK, T1 and T2 treatments were 1.72, 1.58 and 1.51, respectively. Pearson correlation analysis showed that soil nitrification There was a significant correlation between the rate and the denitrification rate and soil moisture content (p <0.05), the correlation coefficients were 0.828 and 0.890, respectively. There was a significant correlation between the nitrification rate and soil water content in T2 (p <0.05), and the correlation coefficient was 0.772.This study showed that ozone concentration increased Soil respiration, nitrification and denitrification rates in winter wheat field were not significantly changed, but the increase of ozone concentration significantly reduced the temperature sensitivity of soil respiration.