灼烧法与化学法测定土壤有机质对比与拟合分析

Comparative and Fitting Analysis Test on Loss-on-ignition Method and Chemical Method for Content of Soil Organic Matter

[目的]土壤有机质是土壤分析测试中一个非常重要的参数,简单准确地测定其值非常必要。[方法]采用两种不同的方法(灼烧法、重铬酸钾容量法)测定土壤中有机质的含量。根据结果分析、讨论灼烧法不同温度适合的灼烧时间,同时与化学方法测得的结果进行对比,分析、比较物理方法与化学方法之间的相关关系,并且整理得出不同温度时两种方法的相关关系式。[结果]350、450、550℃测定24 h比较合适,650℃推荐测定12 h,450℃灼烧法的测定值与化学方法相关性最好(R2=0.946 2),其次为350℃(R2=0.763 7)、550℃(R2=0.581 3)。[结论]由于650℃测定结果比真值偏高,所以不建议采用650℃进行灼烧法的测定。

[Objective] Soil oganic matter（ SOM） is a very important parameter in soil testing and analyzing. It is necessary to use a simple and accurate method to measure SOM. [Method] Two different methods（ loss-on-ignition method and potassium dichromate volumetric method） were used to measure the value of SOM. Based on the results of the experiment,the fitted time for the suited temperature was analyzed and discussed. And the two different methods were compared,then the relationship between them was got. [Result]Appropriate time for 350,450,550 ℃ was 24 h,and for 650 ℃ was 12 h. The correlation between potassium dichromate volumetric method and 450 ℃ loss-on-ignition method（ R^2= 0. 946 2） was better,followed by 350 ℃（ R^2= 0. 763 7）,550℃（ R^2= 0. 581 3）. [Conclusion] Due to the result of 650 ℃loss-on-ignition method was higher than the true value,650 ℃ loss-on-ignition method wasn＇t suggested.