Japanese Journal of Soil Science and Plant Nutrition

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After the results of soil survey work, made recently in the arable areas of Kanagawa Prefec., the map and key for the soil types were published acompanied with some results of chemical analysescof soils. Soil types (after European idea) numbered 7,of which 4 types (Half-bog soils, Meadow soils, Gray lowland soils and Brown lowland soils) were in the rice field, 3 types (Brown forest soils, Rust-coloured forest soils and Colluvial soils) in upland field or forested area (see Table 1 and the map). Of the chemical nature of each soil types the following results were obvious (see Table 2). 1) Of Brown forest soils the degree of calcium saturation increased toward the surface horizon. This inclination may be considered to be due to the result of cultivation, for there was a considerable difference in the degrees between the surface soil of forested area and that of cultivated area in the similar locality, the latter was more saturated with the calcium than the former. Of three principal localities (Tama-hilly area, Sagami-hara upland and Miura Penninsula upland) occupied by Brown forst soils, soil parent materials were compared among them in their calciumsaturation degrees. The degree was highest with the soils from Miura and became lower gradually in the order, Sagami and Tama. Of this tendency of the degree the following consideration was made. Among these areas, Tama area elevated most early followed by Sagami and Miura area is considered to have elevated most recently;consequently these areas may have been subdued to the leaching action differently. The action was most severe with Tama areas rather moderatly with Sagami area and most feeble with Miura area, causing the degree of calcium saturation being higher in the following order, Miura, Sagami and Tama. 2) Of colluvial soils no distinct inclination was observed in their calcium-saturation degrees. 3) Of ground water soil types such as Half-bog soils, Meadow soils, Gray lowland soils and Brown low land soils, there was an inclination of the calciumsaturation being increased toward subsoils(G) except of Brown lowland soils.This induced us to believe an existence of leaching phenomena among these soil types. 4) Point of exchange neutrality had a tendency to increase its number toward the subsoil. This increase may be due to the decreasing of humus conent.

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In this paper, the author investigated types of humic acid of the paddy rice soils. The results are summarized as follows : 1. Humic acid extracted with NaF from soil were chiefly composed of SIMON's true humic acid, both type A and B. 2. In general, reletive color values (SIMON's RF) of humic acid extracted with NaOH from soil, were lower than those of humic acid extracted with NaF. But in some cases, there were found soil having humic acid of very high RF values in the former fraction. These humic acid probably belonged to true humic acid, predominently type A. 3. In a soil, where a large quantity of lime were fertilized for many years, and soil reaction had become alkaline, humus have had properties like those of chernozem.

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A new apparatus for measuring the sorption of water vapor by the soil was equipped. The main part of this apparatus is spring-balance of quartz, and the amount of water vapor adsorbed or desorbed is directly determined. Sigmoid curves showing the relation between the water vapor and the soil moisture content were obtained with several soil samples. The influense of replaceable bases on the sorption of water vapor by the soil was also investigated.

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The utilization of nitrogen supplied after heading by rice plant was studied using labelled ammonium sulfate. When the plant are harvested, 35% of this nitrogen is distributed in the ears. (Table 1). The isotope concentration of various proteins in the brown rice are almost equal except prolamin (Table 2). The relationship between these results and nitrogen translocation in the plant during the maturing stage is discussed.

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