Silvia Ratto

Boron Spatial Variability and Evaluation of Soil Fertility

During last years spatial distribution of soil properties has demanded a considerable investigation effort. The site specific recommendation and a more intelligent use of the resources have raised the need for knowing field-scale variability of soil properties. Soil spatial variability is related to parent material, soil formation process and position in the landscape. The level of variability associated with any estimate of soil property will require an associated estimate of the variability of that property for a scale that is pertinent to the research issue being considered (Cambardella et al., 1994). The classical statistical methods consider that variation is randomly distributed within mapping units. Soil property frequently exhibits spatial dependency. When the objective is to know the fertility of a real soil in an agro-system, site-specific variability is one of the major points to consider for a reliable fertility diagnosis. In the past few years several studies have been carried out in the Argentinean Pampas that confirm the response of sunflower crop to the boron leaf fertilisation (Diggs et al., 1992) and the relationship between extractable boron and other soil properties (Ratto et al., 1999). Wheat, alfalfa, cotton and other crops have also shown responses to the addition of boron. Management of fertilisation technology for each place and crop is of great concern.