| 臭氧浓度升高对冬小麦田土壤呼吸、硝化和反硝化作用的影响 |
| 摘要点击 2469 全文点击 1124 投稿时间：2010-01-18 修订日期：2010-04-05 |
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| 中文关键词 臭氧 农田 土壤呼吸 硝化作用 反硝化作用 |
| 英文关键词 ozone farmland soil respiration nitrification denitrification |
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| 中文摘要 |
| 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. |
| 英文摘要 |
| Field experiments were carried out in a winter wheat farmland, in order to investigate the effects of elevated ozone concentration on soil respiration, nitrification and denitrification. Three ozone concentration treatments, which were CK, T1 (100 nL·L-1) and T2 (150 nL·L-1), were arranged using open top chambers (OTCs). A portable soil CO2 fluxes system was used to measure soil respiration rates. Nitrification and denitrification rates were determined by using a Barometric Process Separation (BaPS) method. Results indicated that there were no significant differences (p>0.05) in soil respiration rates among CK,T1 and T2 treatments. Mean soil respiration rates for CK,T1 and T2 treatments were (5.36±0.72), (5.08±0.04), (4.94±0.18) μmol·(m2·s)-1, respectively. No significant differences (p>0.05) in mean soil nitrification and denitrification rates were observed between the treatments of CK and T2. During the experimental period, soil respiration showed an exponential relationship with soil temperature for each of the treatment. The Q10 (the respiratory flux at one temperature over the flux at a temperature 10 ℃ lower) values were 1.72, 1.58 and 1.51 for CK, T1 and T2 treatments, respectively. A correlation (Pearson product-momentum correlation) analysis showed that soil water content was correlated significantly (p<0.05) with soil nitrification (R=0.828) and denitrification (R=0.890) rates for CK treatment. Soil water content was correlated significantly (p<0.05) with soil nitrification rate for T2 treatment, with the correlation coefficient of 0.772. This study indicated that elevated ozone concentration did not significantly affect soil respiration, nitrification and denitrification rates in the winter wheat farmland. Elevated ozone concentration, however, significantly reduced the temperature sensitvity of soil respiration. |
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