|
Vines can survive in a great diversity of soils. The main requirement is that soils should not be too damp. However, to obtain real quality it is necessary for the soil to achieve a balance of positive conditions, physical and chemical.
One aspect which needs to be taken into account is soil structure -that is, its particular combination of physical elements (clay, silica, chalk, humus). The most suitable soils are those capable of maintaining underground air pockets, which allow the plants' roots to breathe. Another important aspect is texture, a result of the relative proportion of finer elements such as clay, lime and sand. Structure and texture determine a soil’s compactness, its permeability to air and water and its retentive capacity. These, in turn, determine the ease with which the roots can grow through the different soil layers and how well excess water runs off the soil.
Other important factors are, firstly, the depth of the topsoil that can be explored by the plant's roots; secondly, soil temperature, which affects biological processes taking place in the earth; thirdly, the soil's colour, witch influences its temperature and the air closest to it, affecting the final ripening of the fruit; fourthly, the soil's stoniness -that is, the presence of stones or small pebbles, which can help by improving the aeration and health of the roots; and, finally, the soil's composition, since this determines the mineral substances necessary for the vine's existence. Thus, for example, phosphorus, calcium and potassium all positively affect quality while high levels of nitrogen and organic matter yield larger harvests but diminish the fruit's quality.
|
|
