FERTILISATION GUIDELINES FOR THE TABLE GRAPE INDUSTRY

FOLIAR NUTR ITI ON Plants feed primarily through their roots. Therefore, the optimisation of the root zone for assimilation of nutrients is emphasised. However, foliar nutrition is a useful aid for helping to ensure that plants are functioning optimally, specifically where chemical imbalances occur in the root zone or environmental conditions are unfavourable. Situations where foliar nutrition can make a positive contribution include the following: • Low soil temperatures – in early spring when the soil is still cold and active root growth has not yet commenced, foliar nutrition is the obvious way to supply the vines with nutrients. • Post-stress treatments – the detrimental effect of extreme environmental conditions, like excessive heat or cold, frost, etc. can be combatted with foliar nutrition. • Rectification of nutrient deficiencies – deficiencies of specifically trace elements can be rectified during the season. • Unfavourable chemical conditions in the soil – where chemical imbalances, e.g. high pH impedes, the uptake of nutrients, specifically trace elements, foliar nutrition can be used to rectify the deficiencies. • Supplying of nutrients where root systems are damaged or infected. The effectiveness of the foliar nutrition may be raised through the addition of products that contain plant hormones like cytokinin and auxin. Many of the foliar nutrients contain these products already.

92 | PRACTICAL GUIDELINES FOR IMPLEMENTATION OF THE FERTILISATION PROGRAMME