On the Change in the Spatial Vittern and Spatial Structure of Soil Moisture and Bulk Density caused by Soil Management

Abstract

Effect of soil management on the spatial variability of the soil's physical properties of a double-crop paddy field was examined using statistical methods such as geostatistics. Samples were collected along three transects at 0.5 or 1.5mintervals after the wheat and rice harvest in one paddy fi eld and additional samples were collected along two transects at 3 m intervals before and after soil pudding in another paddy field. All samples were collected from the soil surface and were 100ml in volume. Variables include soil moisture content by weight, soil moisture content by volume and bulk density. The results are summarized as follows:
1. The spatial pattern of soil moisture and bulk density was greatly changed before and after soil puddling.
2. Almost all of the semi-variograms of soil moisture and bulk density of soils, collected after wheat and rice harvest, showed the “pure nugget effect” and no spatial structure was observed.
3. From these results, it was considered that both rotary tilling and soil puddling made the topsoil of a paddy field uniform and the spatial structure made by this management has been maintained temporally.