Spatial variability of some physical properties in arable soils of different texture with regard to soil compaction
2005
Širáň, M.,Soil Science and Conservation Research Institute, Bratislava (Slovak Republic)
In this paper the spatial variability of soil physical properties in dependence on sampling area (sampling from the centre of the site of area of 1 square m opposite area of 314 square m - area of monitoring site) and different soil texture (light - sandy, medium heavy - loamy and heavy - clayey soil) are analysed. Physical properties needed to assess soil compaction as bulk density (pd), total or no-capillary porosity (PT or PN), maximal capillary capacity (MCC), retention water capacity (RWC) and minimal air capacity (MAC) are compared. Within followed localities influence of compacting by means of farm mechanisms on arable soil is indisputable. In two used ways of sampling significant differences at pd, PT, PN a MAC between topsoil and subsoil within single soil profiles and all soil textures were found out (excepting sampling from the centre of the site on heavy soil), whereas subsoil was more compacted (cumulative effect of all pressures on soil). In the case of comparison of sampling ways (sampling area size of 1 square m opposite 314 square m), the sampling from the centre of the site showed as not representative in the scope of subsoil on light soil and topsoil on heavy soil. PN, MAC, PT a pd opposite MCC and RWC were more variable then single soil properties. It is interesting that only slightly higher variability of the majority of measured physical properties was in subsoil by sampling from the centre of the site (1 square m) and, on the contrary, in topsoil only with more expressive distinction at sampling from the whole site (314 square m) by the all soil textures. With reduction of sampling area the risk of the site to be not-representative increases (mainly in topsoil) and, on the contrary, with its enlargement the variability of followed properties can decrease (first of all in subsoil).
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