Spatial variability analysis of soil properties in a hilly upland field
2004
Kashiwagi, J. (Hokkaido Univ., Sapporo (Japan))
Abstract Spatial variability of soil properties was studied by using correlation analysis with landscape and geostatistical concepts on a 1.2-ha upland field in a hilly area. Soil properties of Ap horizon were examined on a square grid at 14-m intervals and on three transects at 7-m intervals. The CV values suggested that the variabilities of most soil properties were higher than the results reported at any topographical conditions. These large variables depend on the result of soil erosion and sedimentation in response to the landscape. At the eroded area, the thickness of Ap horizon had been kept constant with subsoil by tillage, as a result Ap horizon was composed of different soil materials from sedimentation and erosion effects. The spatial variability of pH, total carbon content, phosphate absorption coefficient, bulk density, stone, sand, silt and clay content could be explained with topographical features ; however, available water content was difficult to explain. Moreover, former properties were distinguished at landscape model units, these contribute to the rational soil sampling system to realize regional soil management. The multiple regression models of total carbon and stone content, using only topographic attributes calculated from a digital elevation model (DEM), matched reasonably well with the observed data.
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