ALUMINUM RESIDUES ON AND IN GRAPES JUST A S IN MUST AND WINE AFTER APPLICATION OF ULMASUD

In order to determine the aluminium residues on grapes, in must and wi ne after application of Ulmasud an experiment was carried out in the y ears 1989, 1990 and 1992 in a Muller-Thurgau vineyard of the Staatlich es Weinbauinstitut in Freiburg i. Br., Germany. This experiment includ es one control and one Ulmasud variant with three repetitions. Dependi ng on the atmospheric conditions grapevines can take up different trac es of aluminium: 1. from soil through the root (control variant) and 2 . additional from Ulmasud particles over the leaf (Ulmasud variant). T he grapevine distributes this aluminium by means of sap circulation to other organs and also to the berries. Above all, temperature and prec ipitation influence the uptake of aluminium. The adhesivity of the Ulm asud deposit on berries is only moderate. About 80 % to 90 % of the al uminium of the turbid must can be deposited by separation. Aluminium p roved to be absorbed preferentially on must deposit particles. The fer mentation does not influence the Al content. Five, six or seven Ulmasu d applications (1 % suspension) in the vineyard can raise the Al conte nt of wine to between 0.2 mg/l and 1 mg/l depending upon atmospheric c onditions. The permissible maximal quantity of aluminium for wine (8 m g/l) was by no means reached or exceeded.