酸性土壤有机碳两种测定方法的比较

土壤有机质虽然占矿质土壤总量的比例很小,但对土壤质量及功能的调节起着关键作用。因此,寻求合适的土壤有机碳测定方法十分重要。本研究以4个长期定位试验(A、B、C、D)为基础,在灵敏度、相关性等方面对外加热法和碳氮仪法作了比较。结果表明:对于酸性土而言无论测定整土还是团聚体有机碳,两种方法的准确度和灵敏度都很高,但外加热法能更灵敏地反应处理间的差异性;两种方法测定结果有很好相关性,但碳氮仪法测定结果较外加热法偏高;由于测定结果存在差异,在科研工作中两种方法不能混用,以免得出错误结论。

Comparison of two methods for determining soil organic carbon in acid soil

Soil organic matter, although accounts for only a small portion of soil solids, plays a key role in soil quality and soil fertility. Therefore, it is very important to apply a suitable method to determine soil organic carbon content. In this study, based on four long-term experiments (A, B, C, D), the sensitivity, accuracy and the correlation between the external heating method and the CN element analyzer method in measuring soil organic carbon were determined. The results showed that both methods had very high sensitivity and accuracy in determining the organic carbon contents among different treat-ments either for the bulk soil or for the aggregate fractions, and they were relatively correlated. However, the external heat-ing method revealed the differences among treatments more sensitively. Otherwise, the two methods should not be mixed when determining organic carbon content to avoid the wrong conclusions.