| 季节性温度升高对落干期消落带土壤氮矿化影响 |
| 摘要点击 2943 全文点击 1251 投稿时间：2015-06-16 修订日期：2015-09-17 |
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| 中文关键词 三峡支流 氮矿化 温度升高 落干期 消落带 |
| 英文关键词 Three Gorge Tributary nitrogen mineralization temperature increasing dry period water level fluctuating zone |
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| 中文摘要 |
| 为揭示季节性温度升高对消落带落干期土壤氮矿化的影响,分别采集三峡支流澎溪河消落带上游和下游两个水文断面,155 m(低)、 165 m(中)和175 m(高)这3个水位高程表层土壤,结合落干期气温变化特点,在25℃ 和35℃ 两个温度下进行恒温培养. 结果表明,消落带土壤总氮和硝态氮在上游断面和高水位高程含量更高,而下游和低水位高程含量更低,铵态氮分布与其相反. 硝态氮是无机氮的主要存在形式,占无机氮的57.4%~84.7%. 相同培养温度下,氨化、 硝化、 净氮矿化速率均表现为随水位高程增加,随流域断面由下至上而显著增加(P < 0.05); 总体上,在水位高程和流域断面上均表现为:温度升高使硝化速率和净氮矿化速率显著增加(P < 0.05),而对土壤氨化速率无显著影响(P > 0.05). |
| 英文摘要 |
| To reveal the effect of seasonal temperature increasing on nitrogen mineralization in soil of the water level fluctuating soil zone of three gorge reservoir areas in the Yangtze river tributary during the dry period, surface soils were collected from the water level fluctuating zone of Pengxi river crossing two hydrological sections, i.e. upstream and downstream and three water level altitudes, 155 m (low), 165 m (middle) and 175 m (high). We incubated the soil at 25℃ and 35℃ to determine the transformation rates of nitrogen in soil of Pengxi river basin during the dry period. The result showed that TN and NO3--N contents in the soil of upstream section and higher (175 m) altitude of water level were higher than those in downstream and low (165 m) altitude of water level, whereas the pattern for NH4+-N was different, with higher NH4+-N contents in downstream and low water level. The inorganic nitrogen was dominated by NO3--N, which accounted for up to 57.4%-84.7% of inorganic nitrogen. Generally, soil ammoniation, nitration and net N mineralization increased with the rising water level altitude and stream sections(P < 0.05). In summary, nitration and net N mineralization significantly increased with increasing temperature, (P < 0.05), while ammoniation showed no difference(P > 0.05). |
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