One hundred and twelve soi1 samples were collected from various parts in Japan and analyzed or their iodine contents, and the results are considered in the light of the geological system, soil classes, conditions and the pH values of soils ; and the following summary is given : l) A majority of soils contained 1.0-3.0 p. p. m. of iodine, and 15.51% soils contained more than 10.0 p. p. m. The largest iodine content was 56.53 p. p. m. and the smallest, 0.49 p. p. m., and the average for all the soils was 7.41 p. p. m. 2) The soils form the older quaternary period contained the largest amount of idine followed by the younger in the same period. 3) The clayey soils contained the largest amount of iodine which was followed by the loam, sand and sandy loam in the order. 4) The soils of larger pH contained more iodine on the average. 5) The soils from the dry-farm contained iodine, almost double the amount of those from the paddy-field. Considering the foregoing results in comparison with those data which had been reported by the investigators in other countries, the soils in Japan, in general, contain more iodine than those in other countries.
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