An approach to zoning in the wine growing regions of 'Jerez-Xérès-Sherry' and 'Manzanilla-Sanlúcar de Barrameda' (Cádiz, Spain)

The Appellations of Origin "Jerez-Xérès-Sherry" and "Manzanilla-Sanlúcar de Barrameda" occupy one of the oldest and most world renowned viticultural areas in the peninsula, but it is not exempt from the serious problems that are to be found throughout the sector. In order to try to adapt to the present situation, zoning plans are being promoted whereby priority is given to the quality of the product, sustainable development and the economic interests. This work undertakes an approach to the viticultural zoning. The nutritional state of the grapevines is studied by means of foliage analysis at veraison. The quality of production was measured by means of the berry weight and the analysis of the most usual variables of the must at the time of harvest (°Baumé, pH and titratable acidity) over five seasons, in the 21 plots where the soil profiles were opened for analysis. As a result of applying statistical analysis, the plots are grouped into five classes, two of which are subdivided. The most significant differences were established between the plots of class CL1, on Miocene limestone, and those of class CL5, on Pliocene-Quaternary sands and clays. Class CL1 presented the highest content of ash (mean ± sd CL1; CL5) (15.36 ± 1.73; 12.36 ± 1.77) and calcium (3.42 ± 0.90; 2.65 ± 0.72), the lowest berry weight (2.10 ± 0.30; 2.47 ± 0.50) and a greater Baumé degree (10.55 ± 0.86; 9.63 ± 0.98) than the CL5. This new approach takes other essential factors for the quality of the production into account such as the climate and the geomorphology (altitude, slope, and physiography).