摘要
对松嫩平原旱地、水田和草地3种不同土地利用类型的黑土进行了为期90天的实验室培养。研究发现,土壤呼吸强度表现为在初期达到一个最大值后不断下降,随后趋于稳定。4个不同温度条件下(5℃、15℃、25℃和35℃),各类型土壤的呼吸强度均随温度的升高而同步增强。在相同温度条件下,土壤呼吸强度强弱顺序为:水田黑土>草地黑土>旱地黑土。土壤呼吸的温度敏感性系数Q10随温度的升高而减小,这意味着低温区域土壤有机碳对气候变暖的反馈将更敏感。采用一级动力学方程进行土壤呼吸动态拟合,3种黑土活性有机碳含量以水田黑土最高,旱地黑土次之,草地黑土最低;活性有机碳占总有机碳的比例由高到低则依次为草地黑土、旱地黑土和水田黑土。通过密度分选划分了轻组和重组组分,发现土壤样品中重组组分占总有机碳量的95%以上,要大大高于轻组。密度分选与模型拟合的结果基本吻合,轻组碳(活性碳)占总有机碳的比例大小均是草地黑土>旱地黑土>水田黑土,重组碳(缓效性碳)比例则相反。
The black soil samples from three different land use types in the Song-nen Plain were incubated for 90 days in the laboratory.It was found that after reaching a maximum value at the initial stage,the rates of soil respiration declined continuously and then stabilized.At the four different temperature conditions（5 ℃,15 ℃,25 ℃ and 35 ℃）,the rates of soil respiration simultaneously increased with increasing temperatures.At the same temperature conditions,intensity sequence of soil respiration rates of the different samples was as followed： black soil from the paddy fieldblack soil from the grasslandblack soil from the dry land.The values of temperature sensitivity coefficient Q10 of soil respiration decreased with increasing temperatures,which means that the feedback of soil organic carbon to the climate warming would be more sensitive at the colder regions.Soil respiration dynamics was fitted with the first-order kinetic equation.It was showed that among the three types of black soils,black soil from the paddy field had the highest content of active organic carbon,followed by that from the dry land and then that from the grassland;as to the proportion of active organic carbon to total organic carbon,black soil from the grassland was the highest,followed by that from the dry land and then that from the paddy field.Light fraction and heavy fraction of organic carbon in the samples were divided by the density separation,and it was found that more than 95% of total organic carbon in the samples was in the form of heavy fraction,which was much higher than the amount of light fraction.The result from the density separation coincides with that from the model fitting,and the proportion of light fraction（active carbon） to total organic carbon was arranged as followed： black soil from the grasslandblack soil from dry landblack soil from paddy field,while that of heavy fraction（slow carbon） was the opposite.
出处
《现代地质》
CAS
CSCD
北大核心
2011年第3期553-561,共9页
Geoscience
基金
国土资源部公益性行业科研专项"中国主要农耕区土壤碳库与固碳潜力研究"(200911020)
中央高校基本科研业务费专项"我国高原冻土碳的温度敏感性研究"(2010ZY17)
关键词
松嫩平原
黑土
土壤呼吸
温度敏感性系数
活性有机碳
Song-nen Plain
black soil
soil respiration
temperature sensitivity coefficient
active organic carbon
