Spatial variability of soil respiration in a larch plantation: estimation of the number of sampling points required

The objective of this study was to determine the spatial variability of soil respiration and the number of the sampling points required to get a representative value of soil respiration within an ecosystem. In late August 2000, two measurements of soil respiration were conducted at a larch (Larix kaempferi) plantation in Hokkaido, Japan, with the static alkali absorption method (AA method) improved by Kirita [Jpn. J. Ecol. 21 (1971) 119]. The spatial variability of soil respiration rates among 50 sampling points within a 30 m x 30 m plot, was described by the coefficient of variation (CV) of each series of measurements. The average CV was 28%. The average number of sampling points required to estimate soil respiration within 10 and 20% of its actual mean, at the 95% probability level, was estimated to be 30 and 8, respectively. Soil temperature and moisture content did not contribute to the spatial variability of soil respiration in the present site, suggesting that these two factors have a greater influence on the temporal variability of soil respiration than on the spatial variability of soil respiration. (C) 2002 Elsevier Science B.V. All rights reserved.