Abstract
The authors examined the relation between the observation scales of land and the variation in the distribution of physical properties of soils sampled from Hachinohe-Heigen region.
The results obtained are summarized as follows:
(1) The population mean x of the primary variation (L0 population) is equal to the population mean g (Li) of the L1 population, L2 population.
(2) The population variance V (Li) varies with the different observation scales L.
(3) With increase of sampled area F, the converging ratio into zero of the variation between classes B (F) of the dry density (γd) was faster than those of the moisture content (ω) and other physical properties of soils.
(4) In case of hundreds ha scale research, the population mean of sampled area becomes identical with that of total sampled area when the rate of sampled area to total sampled area reaches 30-40% or more for dry density (γd), and 70-80% or more for moisture content (ω), respectively.
(5) Conventional sampler (φ 50 mm in diameter and 100 ml in volume) is not so inconvenient to carry out the investigation for dry density (γd) and moisture content (ω).
(6) Among sampling density (ρs), mesh sampling interval (δ) and sampled area (F), approximate formulas are established as follows:
δ=K1·F1/2
ρs=K2·F-1(K1, K2: constants)
