采用重铬酸钾氧化-分光光度法对影响土壤有机碳含量的测定进行了研究，得知测定有机碳含量的最佳加热温度是140℃，加热时间是40 min，测试波长是589 nm，显色时间是0 min。然后对这些最佳条件进行了方法验证，计算出方法检出限为0.03%，相对标准偏差为0.8%~3.8%，加标回收率为101%~116%。与滴定法和重量法相比，重铬酸钾氧化-分光光度法具有更高的精密性和准确性。

Potassium dichromate oxidation-spectrophotometry method is used to determine the content of organic carbon in soil.It is found that the optimum heating temperature for determining the content of organic carbon is 140℃,heating time is 40 min,testing wavelength is 589 nm,and color rendering time is 0 min.The optimum conditions are then performed for method validation.It is obtained through calculation that the detection limit is 0.03%,the relative standard deviation is 0.8%-3.8%,and the recovery is 101%-116%.Compared with titration method and gravimetric method,the potassium dichromate oxidation-spectrophotometry method shows higher precision and accuracy.