Most soils derived from volcanic ash and pumice show distinctive properties that are not found in soils derived from other parent materials under the same vegetation and climate. Thorp and Smith (1949) first recognized them as a great soil group and gave them the tentative name Ando soils; Ando means dark soils in Japanese. They noted a wide distribution of these soils in deposits of volcanic ash not only in Japan but in other parts of the world. The Ando soils consist, primarily, of dark brown to black A1 horizons, averaging about 30 cm thick, of fine crumb or granular structure with the organic content close to 8% on average and ranging up to 30% in the darkest members of the group. Some members of the group have distinct B horizons with more clay than A horizons, but the younger members are essentially AC soils. The soils have low exchangeable “bases” and occur in humid to perhumid climates with temperature efficiency ranging from cool mesothermal to tropical. Natural vegetation varies from place to place and includes broad-leaved and coniferous forest types often with an understory of bamboo. Thorp and Smith (1949) had some difficulty in deciding whether Ando soils should be placed in the zonal or intrazonal orders, because they did not know whether the dark color of the soils was caused by vegetation or by the soils’ parent material.

The Distinctive Properties of Andosols

Rhizobial denitrification: A review

Effects of nutritional and environmental conditions on Sinorhizobium meliloti biofilm formation.

Agricultural intensification, soil biodiversity and ecosystem function in the tropics: the role of nitrogen-fixing bacteria

Fast-growing, acid-producing soybean rhizobia were examined to determine their biochemical relatedness to each other, to typical slow-growing Rhizobium japonicum strains, and to other fast-growing species of Rhizobium. Although both the fast- and slow-growing soybean rhizobia were positive for catalase, urease, oxidase, nitrate reductase, and penicillinase, the fast-growing strains grouped with other fast-growing species of Rhizobium in that they tolerated 2% NaCl, were capable of growth at pH 9.5, utilized a large variety of carbohydrates (notably disaccharides), and produced serum zones in litmus milk. In addition, these fast-growing strains were similar to other fast-growing species of Rhizobium in that they produced appreciable levels of β-galactosidase and nicotinamide adenine dinucleotide phosphate-linked 6-phosphogluconate dehydrogenase but had no detectable hydrogenase activity. The fast-growing soybean rhizobia share symbiotic host specificity with Bradyrhizobium japonicum, but appear to be related biochemically to the other fast-growing species of Rhizobium.

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Biochemical Characterization of Fast- and Slow-Growing Rhizobia That Nodulate Soybeans

Nitrate reduction in Rhizobium was previously shown to be so diverse that in addition to assimilatory reduction, it includes dissimilatory as well as defective reduction of nitrate (1–5). Little attention seems, however, to have been given to these early results, presumably because they were published in Japanese. Such a situation explains the recent appearance of the paper entitled “Denitrification in Rhizobium” (6). Denitrification by a nitrogen fixer such as Spirillum has also recently been reported (7–9).

Note on nitrate reduction in Rhizobium.

Studies on the Root-Nodule Bacteria of Leguminous Plants. : I. Characters in Artificial Media. Part 3. Physiological Characters (f) : Carbon Source (Growth and Fermentation)

The microbiological characterization of Japanese soils has been one of main themes in the authors' laboratory, and it has been proved that volcanogenous soil is characterized by smaller number of bacteria and larger number of actinomycetes than non-volcanogenous soil (1) Such difference in microflora of both soil groups is considered to reflect the difference between the properties inherent in each soil As the next step, it seems quite reasonable to consider whether there exists qualitative difference in each group of microorganisms

Actinomycete flora of japanese soils:II. Seasonal Change of Actinomycete Flora; (A) On the Basis of Morphological and Cultural Characters

https://www.tandfonline.com/doi/pdf/10.1080/00380768.1969.10432788

ACTINOMYCETE FLORA OF JAPANESE SOILS : III. Actinomycete Flora of Paddy Soils : (A) On the Basis of Morphological, Cultural and Biochemical Characters

Studies on the Root-Nodule Bacteria of Leguminous Plants : II. Relationship between Nodule Bacteria and Leguminous Plants Part 2. From the View of Notrogen Fixation b. Experiments on Cowpea group (2)

Shuichi Ishizawa

Papers

Note on nitrate reduction in Rhizobium.

Studies on the Root-Nodule Bacteria of Leguminous Plants. : I. Characters in Artificial Media. Part 3. Physiological Characters (f) : Carbon Source (Growth and Fermentation)

Actinomycete flora of japanese soils:II. Seasonal Change of Actinomycete Flora; (A) On the Basis of Morphological and Cultural Characters

ACTINOMYCETE FLORA OF JAPANESE SOILS : III. Actinomycete Flora of Paddy Soils : (A) On the Basis of Morphological, Cultural and Biochemical Characters

Studies on the Root-Nodule Bacteria of Leguminous Plants : II. Relationship between Nodule Bacteria and Leguminous Plants Part 2. From the View of Notrogen Fixation b. Experiments on Cowpea group (2)