Ichiro Yamane

EFFECT OF TEMPERATURE ON THE DECOMPOSITION OF ORGANIC SUBSTANCES IN FLOODED SOIL

Abstract In discussing the seasonal and locational difference in the metabolism of rice soil, it is of primary necessity to know how various reactions in soil are changed by temperature.

DECOMPOSITION OF GLUCOSE AND GAS FORMATION IN FLOODED SOIL

Abstract Glucose is often added to the soil in the incubation experiment, in order to accelerate the reduction process.

INITIAL RAPID DROP OF OXIDATION-REDUCTION POTENTIAL IN SUBMERGED AIR-DRIED SOILS

Abstract When air-dried soils are incubated under flooded condition, Eh falls rapidly and then rises again within 24 hr. This phenomenon has already been recognized by TAKAI et al. (1).

Decomposition of Plant Constituents and Gas Formation in Flooded Soil

Abstract The outbreak of gaseous bubbles from paddy rice field, especially in the midsummer, is a conspicuous phenomenon which can not be overlooked by farmers. The gas consists largely of methane with small amounts of carbon dioxide, nitrogen and hydrogen.

Nitrate reduction and denitrification in flooded soils

Abstract It has been well known that the utilization rate of ammonium sulfate fertilizer by lowland rice was as low as 40 percent of the applied ammonium. This low utilization rate was due to nitrogen loss from the paddy field. There are problems as to whether the loss of nitrogen from the flooded soil was caused by the nitrification of ammonium nitrogen and its subsequent denitrification, by the evaporation of ammonium, or by the leaching of ammonium-nitrogen with percolated water. Shioiri and his associatesll clarified that this loss of nitrogen resulted largely from denitrification through nitrate reduction in 1942. After the paddy soil is flooded with water, the oxygen in furrow slice is consumed by aerobic microorganisms, and then the soil becomes reductive. Conversely the oxigen is supplied to the soil through the water from the air, and from various kinds of algae and duckweeds, which produce oxygen through photosynthesis. At the early stage the reduction by oxygen consumption is superior to the ox...

Decomposition of Organic Acids and Gas Formation in Flooded Soil

Abstract Methane is formed by the specific bacteria which are strictly anaerobic. All of the methane bacteria can not decompose the more usual substrates for bacteria such as carbohydrates and amino acids. They can use only alcohol, volatile fatty acids, and gases such as CO2, CO and H2 as their substrates1).

On the interlamellar complex between montmorillonite and organic substance in certain soil

Abstract KODAMA and SCHNITZER (1) have shown that organic substance of the fluvic acid fraction separated from a podzol soil could penetrate into the interlamellar region of montmorillonite. But the natural occurence of such a complex has not been observed yet (2).

Reduction of nitrate and sulfate in submerged soils with special reference to redox potential and water-soluble sugar content of soils

Abstract The ability of the soil to reduce some substances under submerged condition is one of the important soil properties in the management of lowland rice fields. The author thinks that this ability can be indicated by the reduction rate of the oxidized form of some substances in soils under submerged condition and can be called the reducing ability of the soil. This ability is thought to be related to the state of reduction of soil and the amount of hydrogen donors and their precursors for the reduction. The state of reduction can be indicated by the redox potential. The author selected the watersoluble sugar as the example of the hydrogen donor or their precursor, because appreciable amounts of carbohydrates, water soluble and insoluble, are present in soils. To elucidate the relationships between the redox potential, the water soluble sugars and the reducing ability of the soil, the following experiments were carried out, using the soils incubated in a laboratory and from a lowland rice field.

METHOD OF EXTRACTING ORGANIC ACID FROM FLOODED SOIL

Abstract Investigations on the extraction and determination of organic acids in flooded soil have been reported by TAKAI (1) and TAKIJIMA (2). TAKAI applied water to extract acids from soil and determined them by BULLENs method (3). However, TAKIJIMA reported that organic acid could not be completely extracted by TAKAIs procedure, especially in soil with a high organic matter content such as muck and peaty soils, and proposed an extraction procedure with 0.5 N sulfuric acid. He also discussed the absorption of acids by soil.