摘要
采用动态密闭气室红外ＣＯ２ 分析法（ＩＲＧＡ）对黄土高原丘陵沟壑区不同地形的封育草地土壤呼吸速率日动态进行了测定，并分析了土壤呼吸与土壤温度、土壤水分、地下生物量和地形间的关系。研究结果显示，草地的土壤呼吸日动态呈单峰曲线，最小值为０．３９３～１．１０３μｍｏｌ／（ｍ２·ｓ），出现在凌晨；最大值为１．０３４～１．４０５μｍｏｌ／（ｍ２·ｓ），出现在１４时左右，可以用正弦曲线拟合；而且不同样地间土壤呼吸速率与土壤温度间的关系均可用指数函数描述。土壤日均呼吸速率在不同地形的草地间存在差异，平坦草地为１．２２９μｍｏｌ／（ｍ２·ｓ），东北坡１５°，３０°和４５°草地分别为１．１３８，１．０３３ 和０．８９０μｍｏｌ／（ｍ２·ｓ）；西南坡１５°，３０° 和４５° 草地分别为１．０３６，０．８５９ 和０．３７９μｍｏｌ／（ｍ２·ｓ）；土壤呼吸速率随坡度的增大而减小，东北坡土壤呼吸速率小于西南坡，与不同样地间土壤水分和地下生物量的变化趋势一致，而且研究结果表明土壤呼吸的这种差异主要是受地形影响的土壤水分和地下生物量空间分布差异性决定的，而不同样地间土壤平均温度差异不显著（P＞０．０５）。
The diurnal dynamics of soil respiration in enclosed grasslands of gullied-hilly areas of the Loess Plateau, were measured by closed chamber infrared CO2 gas analyzer and the relationships between soil respiration and soil temperature, soil water content, underground biomass and topography were analyzed. Diurnal soil respiration showed a single-peak curve with the lowest value of 0. 393--1. 103umol/（m2 · s） in the early hours of the morning and a peak value of 1. 034--1. 405 umol/（m2 · s） at 14：00. A sine curve could be fitted to the data and all relationships between soil respiration rate and soil temperature could be depicted by an exponential function. There were differences in soil daily average respiration rate between plots： In flat grassland it was 1. 229 /umol/（m2 · s） ; on north-east facing grassland slopes of 15%, 30%, and 45% it was 1. 138 ,1. 033 and 0. 890umol/（m2 · ss）, respectively, while on similar south-west facing slopes it was 1. 036, 0. 859, and 0. 379 umol/（m2 · ss）, respectively. Soil respiration rate declined as slope increased, and that of south-west facing grassland was lower than that of north-east facing grassland, changes that were consistent with soil water content and underground biomass. These differences were determined by spatial distribution differences of soil water content and underground biomass which were affected by topography, but there was no effect of temperature between plots.
出处
《草业学报》
CSCD
北大核心
2010年第1期42-49,共8页
Acta Prataculturae Sinica
基金
国家自然科学基金项目(30771529)
公益性行业计划项目(nyhyzx07-022)
十一五科技支撑项目(2006BAD16B01)资助
关键词
不同地形
封育草地
土壤呼吸
影响因子
黄土高原
different topography
enclosed grassland
soil respiration
influencing factor
Loess Plateau
