INTEGRATED EVALUATION OF VARIATION IN BIOLOGICAL, CHEMICAL AND PHYSICAL SOIL PROPERTIES

The importance of biological processes for soil functioning is frequen tly stressed. In spite of this, the biological soil component has seld om been used to assess soil quality, while optimal and threshold value s have been identified for many physical and chemical soil parameters. In this investigation, the variation in a number of microbiological, chemical and physical variables was studied on two scales. Small scale s were studied with 52 samples from a single agricultural field, and l arge scales with a set of 26 samples from very diverse agricultural si tes in Sweden. In addition, the functional structures of the two scale s were studied by means of principal component analysis (PCA). The two scales had more similarities than dissimilarities regarding variable variation and functional structures. The relationships between variabl es were, however, more blurred in the large than in the small scales a s the influences of soil structure, climate and cropping practice were larger. The possibilities to reduce the number of variables without l oss of vital information about the soil system are discussed.