SOIL PREPARATION

CHAPTER 5

applied to the soil surface. The operation then starts at the bot- tom of the slope and terraces are constructed sequentially up-slope. • Terraces must slightly slope from the outside to the inside and also slope gently at about 0.5 % over its length to prevent water from ponding. The length of terraces should not exceed 150 m. • Soil on the terraces must be loosened by combining a ripper and an appropriate delve plough after the required ameliorants have been applied to the terrace. In construction, topsoil from each higher terrace must be allowed to spill over, or be placed on the lower terrace (depending on the construction method) to replace topsoil that has been removed. • It is essential to control the sur- face run-off from terraces without causing erosion. For the same reason a cover crop should be established on the slanting slopes between terraces. In Mediterra- nean climates, terraces should be constructed after the winter to

allow sufficient time for the soil to consolidate before the next rain- ing season. • The preferred way of terracing steep slopes for wine grapes, however, is by constructing a small terrace for vehicle traffic between two adjacent rows after deep tillage has been done. The area under the vine rows remains at its original slope. Run-off is removed from the vineyard by the terrace which serves as an artificial waterway. Such a system of terraces gives good results on well-drained soil. • Steep slopes can also be utilised efficiently by training narrowly- planted vines on stakes (“echalas” training system) in between contour roads. Vehicle traffic is restricted to the roads, and all vineyard operations, e.g. spraying, are conducted from the roads. Less land is wasted by the contour roads compared to terraces, topsoil is left undisturbed across the entire vineyard, and more vines per hectare can be planted.

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