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(38-23) Influence of the deeply plough on the heavy metals content and distribution in vineyard soils in La Rioja (Spain). Marin, Alvaro1, Iņigo, Victoria1, Andrades, Marisol1, Alonso-Martirena, Juan Ignacio*,1, 1 Departamento de Agricultura y Alimentacion. CCT.Universidad de La Rioja., Logroņo, Spain ABSTRACT- The use of fertilisers and phytosanitary products, together with the use of farming machinery, have an influence on the heavy metals content and distribution in the soil. In this work, the we have analysed the physicochemical properties and the Cd, Cu, Mn, Ni, Pb and Zn concentrations, both total and bio-available, on the surface and in depth in 38 profiles. The data have been statistically processed through descriptives, correlations and comparison of mean values. The physicochemical properties and the heavy metals content are similar on the surface an in depth, unlike the usual case, since the highest concentrations of organic material and heavy metals are usually located on the surface and their content gradually decreases with depth. The analysis of the existing correlations in the edaphic parameters reveals a positive and significant correlation amongst the organic material, the carbonates and the pH between A and C, although with a different level of significance. These data support, together with the maps obtained from the GIS, the hypothesis of the deeply plough as a cause of the uniformity found in the profile of the vineyard soils under study. The agrochemical contribution tends to increase the heavy metals content but, in this case, the comprehensive mechanical preparation of the soil by deeply plough, a very widespread practice in the area, unifies the profile. The quality of the soils is good: the heavy metals content on the surface is similar to that found in forest soils worldwide and is below the limits set by the Directive 86/278/EEC. The heavy metals content in depth is higher than expected. When the aported metals were mixed within the profile, the superficial values did not increase alarmingly. Nevertheless, the critical load is being saturated, and the soil could become a source instead of a sink. Key words: heavy metals, vineyard, soils, deeply plough |
