Abstract
The usual procedure for determining carbon in soil is to determine carbon by a wet combustion-method (i.e. Nogakukai's method) in our country This procedure is time-consuming and tedious, and requires a large space. A titration method which depends on measurement of K_2Cr_2O_7 or KMnO_4 reduced by the soil organic matter fails to estimate the accurate value of organic carbon in soil in spite of the simpleness of its procedure. In order to exclude such faults, an attempt was examined to establish a new method for determining carbon in soil after the method of Farrington et al. The results of soil analysis by the new method modified from that of Farrington et al satisfied approximately our purposes. The principle of this method is that a soil sample (corresponding to 1-10 mg C) is heated with Van Slyke-Folch's combustion solution in a stream of CO_2-free air, and the CO_2 evolved is absorbed in NaOH solution ; the carbonate thus formed is precipitated as Ba-carbonate and determined acidimetrically. The new method has the advantage of being more expeditious and economical than the usual wet combustion method.
