WINETECH Technical Yearbook 2021

SMU, followed by a numerical figure that involves a further di- vision within the soil form, based on family level, effective depth, stone percentage etc. Each SMU has its own challenges and advantages, and an exper ienced agr i - culturist can make various deductions from studying such a map. Informed de- cisions, like the ne- cessity of drainage, ridging actions, soil preparation actions, irrigation type and schedul ing, and much more, can subsequently be made. Representa-

the soil characteristics and limitations are known, the rootstock that will perform best in the specific soil type can be chosen. The next element that has a significant influence on the vine, is climate. Climate is a very broad term that can also be broken down into individual indices, like the average February temperature and annual rainfall. Although data from the nearest weather stations is very useful to better understand the climate of the immediate area, it cannot point out climatic differences on individual farms. The biggest drivers of climatic differences on farm level is solar radiation, wind and topography. These can be mapped by means of a terrain analysis to illustrate the differences. Climate determining characteristics, like altitude, aspect, slope, solar radiation, day length hours, slope form and flow accumulation, are very useful to depict the finer differences in climate on farm level. This information is very valuable, as cultivars tend to show significant differences when it comes to climatic requirements. This data is obtained through the processing of contour and other terrain data in a GIS system to create a digital terrain model. Terrain information, like slope form and

flow accumulation, is also helpful to draw soil boundaries, because it predicts the groundwater conditions. CONCLUSION These big decisions do not have to be taken alone and it is recommended to involve a soil scientist and viticulturist to help with the process. Collectively, informed block layouts can be drawn on detailed soil and terrain maps in order to create homogeneous blocks with the correct cultivar and rootstock choices. There are free websites available like Cape Farm Mapper of the Department of Agriculture and TerraClim, which is funded by Winetech, where basic soil, climate and terrain data of a farm can be obtained.

FIGURE 1. Example of a block layout based on a soil map.

For more detailed information and personal support, the Vinpro Consultation Service can be contacted at 021 276 0429 to help make the block layout process easier by means of soil mapping, terrain analyses and viticultural consultations.

important basis maps on which planning can be done. A soil map indicates soil dif - ferences in homogeneous soil mapping units (SMUs). Each SMU has a map symbol which describes the soil contained therein. It usually consists of an abbreviation of the soil form that predominantly occurs in the

tive soil samples are then taken according to the soil variation to identify chemical limitations and deficiencies and make re­ commendations. Each cultivar, and especially rootstock, has its own soil requirements and tolerances. If

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