It is recently observed in Kagawa & Okayama prefecture in Japan that paddy field rice plant is often damaged in late July & early August when the season gets hot especially after the top-dressing with am-sulfate & etc. From the inspection of the field the authors suppose that the damage have a close connection with the reduction of am-sulfate & other sulfate-manures applied to soil and tested the reduction of several sulfates in soil of paddy field condition. The results will be summarized as follows; 1. All the soil sampled from the damaged field, reduces sulfate well. 2. The reduction is increased; a) with the amount of sulfate applied. b) with the temperature of incubation, especially above 30℃. c) with pH of soil especially at slight alkaline & neutral and at about pH 3 it stops. d) with the water content of soil. 3. The soil reduces each of Am K. Na. & Ca-sulfate almost equally but not Cu-sulfate. 4. Desinfection stops the reduction. 5. From the above results, the authors conclude that the chief cause of the damage may due to the sulphide formed in soil by the reduction of sulfate manures applied to soil.

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On the mineralization of soybean-cake-N some outdoor experiments were carried out, using certain wooden frames with three sorts of soil under dryfarm conditions without planting. The soil used were all distinctly acid; pH value of which being ca. 4-5. The experiments were purposely made in winter and continued for 123 days. The results obtained may be summerized as follows : The rate of mineralization of soybean-cake-N was accelerated remarkably by the addition of slaked lime to the soils under consideration. In earlier periods of experiments the amount of NH_4-N as well as NO_3-N found in the plots treated with slaked lime was much larger than the one in the plots without slaked lime. It was noticed moreover that a considerably large quantity of NH_4-N still remained in the latter plots at the end.

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The soils containing alkali salts in Tainan prefecture belong to a solonchak, (the underground water soil type) considering from morphological features, physical properties, chemical constituents etc. The exchangeable cations are mainly Mg and Na, though K and Ca also occure, and Ca : (Mg+Na+K) ratio is about 44.6 : 55.4. From these reasons, these solonchaks are considered to be the low-lying flooded alkali soils. According to the climatic conditions, the LANG'S rain factor (74.6) and the MEYER'S N-S quotient (417.2) are higher than those of the climatic alkali soil type. Under these circumstance, the development of these soils require poor drainage as a primary prerequisite for their formation.

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In the preceeding paper the opinions of Dr. W. LAATSCH (Halle) expressed by him in his latest work, Dynamik der deutschen Wald-und Ackerboden (1938) in regard to the "brown forest soils" and allied soil types are interpreted with some critical and explanatory notes. The most important matters to be remarked here are as follows : 1. He designates Ramann's "brown earths" as "brown forest soils" with a very little modification of the original meaning. 2. He rejects the name, "Erubasboden", as unadequate from the evolutional point of view and designates the soils as "immature brown forest soils." 3. He calls the very faintly podsolized varieties "podsolic brown forest soils" and the distinctly podsolized ones "podsolized forest soils" 4. He recognizes the alteration of the "steppe black earths" and "rendzinas" to the "brown forest soils" by degradation. 5. He looks the "rust-stained forest soils" and "brown forest soils" of Prof. H. STREMME as the accidental phases of the "podsolic brown soils" and partly of the "podsolized forest soils" due to the difference of soil texture, the former being sandy and the latter loamy. (The present writer observed another phase in the clayey soils of the western part of Northeast Japan several years ago). LAATSCH'S opinions, above-mentioned, seem to be right for the most part, but the present writer thinks it is unreasonable to incorporate the soils which did not developed under the forest vegetations or whose origins are ambiguous into the group of the "brown forest soils" which are called so from the fact that they are found in the climate of the primitive, deciduous of mixed forests of the Middle Europe. It will surely be better to adopt the term, brown soils instead of the term, "brown forest soils", which is rather complex and liable to be misunderstood, and to use the terms, podsolic brown soils and podsols, instead of the terms, "podsolic brown forest soils" and "podsolized forest soils" respectively.

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