Study of leaf mineral content in vine and four weed species included in the vegetal cover in a Spanish vineyard

Abstract

Castilla-La Mancha region (Spain) is an important viticulture region with 500.000 hectares occupied by vineyards. These vineyards have been traditionally plowed by mechanical traction regarding the arid environment of the region. During late years, farmers are concerned about alternative methods for soil maintaining because of greening policy, CO₂ sequestration, soil erosion, energy balance and sustainable land use. The aim of the present work is to assess the content of some mineral elements (Na, Ca, Mg, K, P, S, Fe, Mn, Si, Al, V, Cr, Cu, Rb, Sr, Ba, Zn, Cs, Nb, Ce, La and Nd) in vine and four weed species leaves (Medicago lupulina L.; Malva sylvestris L., Hordeum murinum L. and Erodium cicutarium L.) included in the natural vegetal cover of a vineyard sited in Ciudad Real province (Central Spain). Samples were picked in May 2015 and 2016, dried, milled and analyzed using the X Ray Fluorescence Technique. The results obtained have been compared with those measured in a vineyard located in a different site and with other ones suggested by the literature for plants in general. Important differences have been found in K, Si, Ca and Zn content, although other elements, such as Mg, P, S, Ba and Nd, remained almost constant regardless the species. Moreover, the influence of the type of soil (different site) can lead to a different composition of the vine leaf in some elements. This last point is especially evident in the case of Sr (more present in calcareous soils and leaves of plants grown on them, reaching 377 mg·kg^-1 versus less than 86 mg·kg^-1 in the non-calcareous studied soil).