Edaphologia

About a thousand individuals of Collembola were collected with bait traps set at the lake shore of Yasaka dam, Hiroshima, Japan. The species resembles Ballistura lamelligera (Borner, 1909) in having tenent hairs on tibiotarsus, but it is clearly different in several features from other species of the genus. It is described here as a new species, B. yasakaensis Tanaka and Niijima.

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Fairy pitta, Pitta brachyura nympha Temminck and Schlegel, 1850, is a migratory bird, the ecology of which is not well known. A small population of the bird breeds in warm-temperate forests in highly limited areas of Southwestern Japan. In view of the importance of conservation of breeding environment for the bird, we investigated nesting site selection of fairy pitta and abundance, biomass and species composition of surface living earthworms as a main food for nestlings, in various types of forest habitats in a warm-temperate region in Kochi Prefecture. All of the three nests found in the study area were in evergreen broad-leaved forests along ravines. A total of 1164 individuals from eight species of Pheretima s. lat. (sensu Ishizuka, 1999) were collected. Topography was a significant factor affecting abundance and biomass of surface living earthworms, with ravine×concave exhibiting the richest community of them. Hinoki cypress, Chamaecyparis obtusa (Sieb. et Zucc.) Endl., plantations tended to be poorer in species richness and diversity. Nine habitat types developed on the basis of a combination of forest type and topography were grouped into four habitat groups in a cluster analysis using abundance, biomass, species richness and species diversity of earthworms as variables. Evergreen broad-leaved forest×ravine×concave, which comprised one habitat group by itself, exhibited the richest community of the surface living earthworms. Based on the agreement between the nesting site of fairy pitta and the site of richest community of surface living earthworms, it was concluded that availability of food resource is one of the most important factors affecting the nesting site selection of fairy pitta.

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Abundance of soil organisms affected by conservation tillage in arable lands. Tomomi Nakamoto (Laboratory of Plant Science for Sustainable Agriculture, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku Yayoi, Tokyo 113-8657, Japan). Conservation tillage is a tillage system that reduces soil disturbance and maintains much of the soil surface covered by plant residues. Advantages of conservation tillage include soil water conservation, soil erosion control, less use of fossil fuels, and laborsaving. Additionally, conservation tillage systems can preserve soil living organisms, which have several beneficial functions in arable fields, such as nutrient cycling, soil structure preservation, and population control of undesirable organisms. This paper reviews the effects of conservation tillage on the abundance of soil organisms. Most groups of soil organisms often have greater abundance or biomass in conservation tillage systems than in conventional tillage systems. This is attributed to improved soil physical properties, such as higher water content and less temperature change, and larger amount of organic matter supply in conservation tillage systems. Reduced tillage, an intermediate form of conservation tillage between conventional tillage and no-tillage, usually gives intermediate results between the two tillage systems. However, the responses of soil organisms to conservation tillage, which greatly vary with tillage methods, residue management, and the combinations of soil, climate, and crop, are more or less unpredictable. Further studies are needed, including attempts to understand interactions between microflora, micro-, meso-, and macrofauna.

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