秦岭火地塘林区不同海拔和坡位森林土壤NO通量研究

发布时间：2018-04-23 22:06

本文选题：秦岭 + 森林　；参考：《西北农林科技大学》2017年硕士论文

【摘要】：氮氧化物在大气化学性质中起着关键作用。虽然一氧化氮(NO)在对流层中存在的时间相对较短,但它对局部以及区域的大气光化学反应具有重要的影响。对区域和全球NO库存进行估算时,不仅要考虑自然和人为因素排放的NO,还应该强调土壤是NO的重要排放源。土壤NO通量随着土壤温度和水分的变化而变化很大,但它们之间的关系很复杂,迄今为止没有明确的结论。因此,需要在不同的气候条件下长时间研究这些关系,并覆盖每个地区的不同季节。本研究选取秦岭火地塘林区不同海拔(1560~2160m)有代表性的5个森林样地以及油松林不同坡位的3个样地,采用静态箱—氮氧化物分析仪法对其土壤NO通量进行1a(2014年10月至2015年10月)的监测。主要研究结论如下:(1)土壤NO排放主要集中在植物生长季(2015年4月至2015年9月),但整个观测期NO排放保持在较低水平。在非生长季(2014年10月至2015年3月),大部分样地的NO排放先减少后增加,而且监测有NO吸收。不同海拔NO年排放总量在0.02~0.19 kg·ha~(-1)·yr~(-1)之间。除华山松外,NO年排放总量随海拔的升高而减少。不同坡位土壤NO年排放通量在中坡位最高(0.11 kg·ha~(-1)·yr~(-1)),上坡位次之(0.09 kg·ha~(-1)·yr~(-1)),下坡位最低(0.06 kg·ha~(-1)·yr~(-1))。(2)不同海拔5个样地土壤NO通量均与地温显著正相关(P0.05)。华山松林土壤NO排放与土壤孔隙充水率(20-40cm)呈负相关(P0.05)。油松林土壤NO排放与土壤铵态氮含量负相关(P0.05)。上坡位土壤NO通量与地温和WFPS显著正相关(P0.05);中坡位土壤NO通量与地温极显著正相关(P0.01),与铵态氮含量显著负相关(P0.05);下坡位NO通量与地温和硝态氮含量显著正相关(P0.05)。(3)土壤温度是影响土壤NO通量的主要因子。除油松林外,各样地的土壤孔隙充水率都低于60%,可以推断,硝化反应是本地区NO的重要生成源,但受到降雨和土壤有机质等理化性质的影响又伴随有反硝化过程。
[Abstract]:Nitrogen oxides play a key role in the chemical properties of the atmosphere. Although the presence of nitric oxide (NO) in the troposphere is relatively short, it has an important impact on the photochemical reactions in the local and regional atmosphere. The estimation of regional and global NO inventory should not only consider the NO of natural and man-made emissions, but also should be emphasized. Soil is an important source of NO emission. Soil NO flux varies greatly with soil temperature and soil moisture, but the relationship between them is very complex. So far, there is no clear conclusion. Therefore, it is necessary to study these relationships for a long time under different climatic conditions and cover the different seasons in each area. This study selects the Qinling Mountains hot pond. The soil NO flux was monitored by static box nitrogen oxide analyzer (October 2014 to October 2015) by the static box nitrogen oxide analyzer. The main conclusions were as follows: (1) the soil NO emission was mainly concentrated in the plant growth season (April 2015 to 2) (from April 2015 to 2), with 5 representative forest plots (1560~2160m) and 3 samples of different slope positions of the pine forest. In September, 015), NO emissions were kept at a lower level during the whole period of observation. In non growing seasons (October 2014 to March 2015), most of the NO emissions were reduced first and then increased, and NO absorption was monitored. The total emission of NO years at different altitudes was between 0.02~0.19 kg. Ha~ (-1) and yr~ (-1). The total emission of NO years, except for Huashan pine, decreased with the elevation of altitude. The NO annual emission flux at different slope positions was the highest in the middle slope position (0.11 kg. Ha~ (-1). Yr~ (-1)), the upper slope (0.09 kg. Ha~ (-1) / yr~ (-1)), and the lowest slope position (0.06). (2) the soil flux and soil pore water flux in the soil of Huashan pine forest and the soil pore water filling rate were all significant. 40cm was negatively correlated (P0.05). The soil NO emission from the soil of Pinus tabulaeformis was negatively correlated with the soil ammonium nitrogen (P0.05). The NO flux in the upper slope was significantly positively correlated with the ground temperature and WFPS (P0.05); the soil NO flux in the middle slope was significantly positively correlated with the ground temperature (P0.01), and was negatively correlated with the ammonium nitrogen content (P0.05), and the NO flux at the downslope and the soil temperature and nitrate nitrogen content showed a significant negative correlation (P0.05). There is a positive correlation (P0.05). (3) soil temperature is the main factor affecting the soil NO flux. In addition to Pinus tabulaeformis forest, the soil pore water filling rate is less than 60%. Nitrification is an important source of NO in the region, but the effects of precipitation and organic matter such as soil organic matter are accompanied by denitrification.

【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S714

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