An in situ lysimeter experiment on soil moisture influence on inorganic nitrogen discharge from forest soil
An in situ lysimeter experiment on soil moisture influence on inorganic nitrogen discharge from forest soil
复制标题
土壤水分对森林土壤无机氮排放影响的原位蒸渗仪试验
DOI：
10.1016/s0022-1694(96)03240-4
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发表时间：
1997
影响因子：
6.4
通讯作者：
Masakazu Suzuki
中科院分区：
文献类型：
--
作者：
N. Ohte;N. Tokuchi;Masakazu Suzuki
利用土柱蒸渗仪在林地进行了土壤水分状况对氨化作用、硝化作用和反硝化作用的影响研究。不同土壤含水量的蒸渗仪排放的NH 4+和NO3-浓度存在明显差异。采用原状土样制作了3种不同类型的蒸渗仪（直径19.5cm，深度30.0cm）。从1991年7月5日至11月29日，在自然降雨条件下，大约每周测量一次从蒸渗仪排放的无机氮。三个蒸渗仪的土壤水分条件使用每个柱底部的平均压头控制在-268.6 hPa，0 hPa和19.8 hPa。这三个水分条件大致对应的条件，在上部或中上部的山坡相对干燥的土壤，较低的山坡相对潮湿的土壤，和河岸带周围的春天点和溪流饱和土壤，分别。在这些土壤水分条件下，观察到三种不同类型的无机氮排放：（1）铵态氮和硝态氮;（2）硝态氮;（3）既不铵态氮也不硝态氮。结果清楚地表明，在饱和条件下，土壤水分亏缺抑制了硝化作用，反硝化作用减少了NO3−。这表明，即使在浅层土壤中，由于土壤水分变化的影响，氮动态过程的不同阶段也可能发生。从每个蒸渗仪的无机氮排放的性质，有助于解释的空间异质性的氮动态所造成的分布在流域系统内的土壤水分条件。
The influences of the soil moisture condition on ammonification, nitrification and denitrification were examined by in situ experiments on forest floors using soil column lysimeters. Distinct differences were detected in the discharge concentrations of NH4+and NO3−from lysimeters with different soil water content. Three types of lysimeters (diameter 19.5 cm, depth 30.0 cm) were prepared by containing undisturbed soil samples. Inorganic nitrogen discharged from lysimeters under natural rainfall was measured approximately once a week from 5 July to 29 November 1991. Soil moisture conditions of the three lysimeters were controlled using an average pressure head at the bottom of each column at -268.6 hPa, 0 hPa, and 19.8 hPa. These three moisture conditions corresponded approximately to the conditions in the upper or mid-upper hillslopes with relatively dry soil, lower hillslopes with relatively wet soil, and riparian zones around spring points and streams with saturated soil, respectively. For these soil moisture conditions, three different types of inorganic nitrogen discharges were observed; (1) ammonium and nitrate nitrogen; (2) nitrate nitrogen; (3) neither ammonium nor nitrate nitrogen. The result clearly showed the restraint of nitrification by soil moisture deficit and the reduction of NO3−by denitrification under saturated conditions. This suggests that the different stages of the process in nitrogen dynamics could occur owing to only the influence of soil moisture variations even in the shallow soil layer. The nature of inorganic nitrogen discharge from each lysimeter helped to explain the spatial heterogeneity of the nitrogen dynamics caused by distributed soil moisture conditions within a watershed system.