Temporal change of soil animals of the stockpiled forest topsoil in relation to soil temperature and soil moisture

Abstract

The number and species of soil animals were counted, and soil temperature and soil moisture were measured monthly for the stockpiled forest topsoil during a three month stockpiling period, and their temporal change and mutual relationships were analyzed. The topsoil, collected from evergreen broad-leaved forest, was stockpiled in a container in an outdoor environment. Every factor was measured at each depth of 0.1, 0.5, 1 and 1.5 m from the soil surface at the horizontal center of the container. As a result, the number and species of soil animals decreased with time, while the temperature and the moisture of the topsoil increased with time at all depths. The soil moisture was higher than 50% at from a 0.5 m to 1.5 m depth, however, the moisture at 0.1 m depth was not as high as those of the 0.5 m-1.5 m depth, probably due to the combined effects of infiltration, drainage and/or evaporation of rainwater in the topsoil layer, which depended on time. The temporal increase in soil temperature was perhaps brought about by the heat produced by the decomposition of the organic matter contained in the topsoil. The temporal decrease in soil animals was probably caused by the soil temperature and soil moisture, which were increased, and became unsuitable for their survival. Since preserving soil animals in the topsoil is crucial for keeping natural revegetation potential of the topsoil and to use it for recycling, rises in soil temperature and in soil moisture of the topsoil must be prevented.