棕壤有机质测定方法研究

A Quick and Sensitive Method for the Quantification of Organic Matterin Brown Soil

本研究采用烘箱加热的方法测定土壤有机质含量,试图探究一种快速、准确测定土壤有机质的方法。为此,以棕壤为例,使用烘箱加热法测定了24个棕壤样品的有机质含量,通过对土壤样品消解温度（100-125℃）和消解时间（30-90 min）的18种梯度组合,分析了改进的烘箱加热法、油浴法与元素分析仪测定结果的差异及适用性。研究表明,18种消解温度和消解时间梯度组合的烘箱加热法测定有机质含量与元素分析仪测定结果相关性均达到极显著水平（r〉0.995）;当消解温度为115℃、消解时间为30 min时,烘箱加热法测定的有机质含量与元素分析仪测定结果的标准偏差和偏差率为最小;与油浴法相比,烘箱加热法测定的土壤有机质含量的准确性提高了12.4%;因此,本改进方法中,对于供试棕壤的最佳消解温度115℃,消解时间为30 min。与传统的油浴加热法相比,烘箱加热法具有操作简单、测定速度快、温度易于控制、减少了环境污染等优点。

The development of a rapid and accurate method for soil organic matter is considered important. The author investigated the feasibility of oven heating method to determine the concentration of soil organic matter. A total of 24 soil samples were collected in Liaoning Province. 6 temperature gradients （100-125℃） and 3 time gradients （30-90 min） were compared with the aim of identifying the best combination to predict soil organic matter. The results showed that： the correlation coefficients （r） of prediction of soil organic matter were above 0.995 when the temperature was ranging from 100% to 125℃ and time was ranging from 30 min to 90 min. In addition, when temperature was 115℃ and time was 30 minutes, standard deviation and percentage deviation were minimum compared with other combination of temperature and time. Compared with the oil heating method, the accuracy had been increased 12.4% using oven heating method. The above results suggested （1） oven heating method in this study is robust and stable enough to be applied for similar soils; （2） determining organic matter in brown soil, the suitable temperature is 115℃ and time is 30 minutes.