Seasonal Uptake of Nutrients by Chenin blanc in Sand Culture: I. Nitrogen

The seasonal uptake and the distribution of nitrogen were determined for Chenin blanc/99R, grown in sand culture under South African conditions. Whole vines were sampled 14 times in the course of one year. Two distinct absorption peaks were found-the first starting after bud burst and lasting up to veraison, while the second extended from harvest into the leaf fall period. The amount of nitrogen absorbed during the second (post harvest) period amounted to 34% of the total for the season, and most of this was stored in the roots. The amount of nitrogen removed by the crop (1,39kg/ton of grapes) compared well with relevant literature, but the amount of nitrogen in leaves and canes associated with this, differed from results obtained in other countries.