In order to understand the mechanism of poor drainage caused by permeated water in a sloped upland field, it was investigated about micro-topography and soil distribution in two sloped upland fields (wheat field, potato field). The results are summarized as follows: 1) The slope in both research fields was, relatively gentle in higher parts, steep in middle parts and gentle in lower parts. 2) The yield of wheat was lowest in the area, where changed from a steep slope to a gentle slope rapidly in lower parts of slope. The depression was crossing in this area. 3) The yield of potato was lowest in the area, where was located in middle parts of slope and changes from a gentle slope to a steep slope rapidly. In the upper part of this area, comparatively big depression disappeared. 4) It was recognized the soil which had low permeability layer in wet injury parts and its boundary point at both fields. Moreover, the inclination of the upper surface of low permeability layer was looser than the terrestrial inclination at both fields. 5) Accordingly, at wheat field, it was considered that permeated water which flowed along depression was gushed in the parts, where changed to a gentle slope rapidly. At potato field, it was thought that permeated water which flowed along depression was gushed in the parts, where changed to a steep slope rapidly. As the inclination of the upper surface of low permeability layer was looser than the terrestrial inclination at both fields, it was considered that the gush was promoted with movement in down and the transverse direction of permeation water being restricted by low permeability layer.

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The relationship between the morphological features of soil profiles and the properties of sedimentary parent material were studied in the Okinawa Colony, the low land zone of East Bolivia. The morphology of soil profile and the property of sedimentary parent material were significantly different between in the northern and southern parts of the Okinawa Colony. In the northern areas, regosols were dominant, and olivine, calcite, plagioclase, potassium feldspar, quartz, chlorite, and mica were main constituents of primary minerals. On the contrary, in the southern areas, red-brown soils were dominant, and olivine, calcite, plagioclase, potassium feldspar, and quartz were main constituents of primary minerals. The composition of clay minerals was also different between the north and the south parts. Illite, vermiculite, and kaolinite were main components of clay minerals in the north, and kaolinite, smectite, and illite were main components in the south. The differences in main elemental composition of fine-sand particles, which were clarified by principal component analyses and cluster analyses, indicated that the profiles characterized as the siliceous cluster were mainly distributed in the north. Contrarily in the south, the profiles characterized as the felsic cluster were mainly distributed.

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We directed our attention to the opal phytoliths originating from family Pinaceae, on which information is relatively scarce among the opal phytoliths of tree origin. In order to clarify the amount and morphological characteristics of the opal phytoliths derived from conifers, leaves of Pinaceae tree belonging to 6 genera and 53 species were employed as samples, which were grown in the University Forest, the Tokyo University (located in Yamabe, Furano citry, Hokkaido, Japan). The contents, morphology, and particles sizes of opal phytoliths isolated from these leaves were determined and compared. The results are summarized as follows: 1. The contents of opal phytoliths in the Pinaceae leaves were distributed in a broad range between 0.03〜1.76%. However, most phytolith contents were lower than 1.10%. Althoug the contents in Larix and Picea leaves were high and larger than 0.50%, the contents in Pinus, Abies, Tsuga, and Pseudotsuga leaves were very low at around 0.1%. 2. The phytoliths were originated mainly from epidermal cells, transfusion tracheid cells, endodermal cells, and stoma cells. More than half of the phytoliths in Pinus, Picea, and Abies leaves were originated from transfusion tracheid cells and endodermal cells. In Larix, opal phytoliths of epidermal cells and intercellular space were dominant, where as other types of opal phytoliths were rarely observed. 3. Phytoliths with a specific morphology were observed for each genus. Characteristics phytoliths were mesophyll phytoliths for Pinus, epidemal phytoliths with sinuous margins for Picea, endodermic phytoliths for Abies, transfusion tracheid phytoliths for Tsuga, epidermal and intercellular space phytoliths for Larix. 4. Very distinctive phytoliths were observed in some conifers, such as sub-epidermal for Pinus Ponderosa, astrosclereids for Douglus fir, epidermal phytoliths with smooth margins for Larix leptolepis, and intercellular space phytoliths for Larix gmelinii. These conifers were clearly distinguishable from on this basis. 5. Size of opal phytoliths from each conifer were generally similar : those from Pinus, Picea, and Abies were rather larger, and those from Tsuga were rather smaller. 6. The phytoliths from conifers can be distinguished only at the level of genera at present except some tree species. However, level by a examination of morphological characteristics and sizes, together with examination of size of bordered pits in transfusion tracheid phytoliths.

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Since the 1980's, damages derived from acid sulfates soils which appeared due to large scale cutting of soils have occurred in Hokkaido. A report on the classification with age or formation factors, properties, and distribution of these soils is introduced. Reports on countermeasures against these soils are also introduced. Subjects on the Japanese soil classification system for acid sulfate soils are described. 1. Acid sulfate soils appearing in Hokkaido are classified by origin of contained sulfur, namely marine deposit or volcano-geneous activities, formed age, and so on. 2. Vegetation on cut slopes of acid sulfate soils was successful by the neutralization method with CaCO_3, but failed by the impermeable method with a sheet of 1 cm thickness. The cost of the neutralization method is cheaper than traditional methods. 3. Countermeasures for acid sulfate soils damage caused by the consolidation in paddy fields were investigated. 4. Causes of drainage pipe clogging in the Mt. Tokachi mud flow distributed area, which consist of volcano-geneous acid sulfate soils, were clarified. Countermeasures using rockwool (calcium silicate) as filling material in ditches of tube drainage were successful. 5. The Japanese soil classification system for acid sulfate soils in Hokkaido seems to be insufficient.

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