Traubenertrag, Mineralstoffgehalt von Blättern und 1‐jährigen Trieben sowie Frostanfälligkeit der Knospen von Vitis vinifera L. bei verschiedenen CI−/SO42−Relationen

Abstract

The influence of different Cl−/SO42− ratios in nutrient solutions applied to vines (Vitis vinifera L), on grape yields, mineral composition of leaves and stems, and bud suspectibility to frostA nutrient culture experiment with vines was carried out to investigate the influence of different Cl−/SO42− ratios on grape yields, the mineral composition of leaves and one year old stems, as well as the frost susceptibility of the buds.Cuttings of the cultivar „Grüner Veltliner”︁ were grown for a two year period in hydroponic cultures before the onset of the experiment in the third year. The four treatments applied which differed only in Cl−/SO42− ratio were as follows, the ratios being expressed in me/l: 1) 4 Cl−/0.5 SO42−, 2) 2.5 Cl−/2.0 SO42−, 3) 1 Cl−/3.5 SO42− and 4) traces of Cl−/4.5 SO42−.The results may be summarized as follows: When the proportion of chloride in the nutrient solution was high (treatments 1 and 2) grape yields were on average only about half those obtained in the higher sulphate treatments (treatments 3 and 4). In the transition from the chloride to sulphate treatments, the Ca, Mg and K contents of the leaves fell. The same was also true for the contents of Fe, Mn, Cu and Zn. In the one year old stems the Fe content increased markedly, and to about the same extent as the fall in Zn content. A distinct negative correlation was observed between the chloride and nitrate contents in the leaves as well as in the one year old stems. The highest frost suspectibility of the buds was obtained with a ratio of 1 me Cl− to 3.5 me SO42−.