Abstract
Experiments were conducted on the effect of hydrogen-ion concentration of cultural solution on the growth of grapevines growing in'the sand or solution culture. The vines used were the cuttings, of Black Queen variety.
In the first experiment, vines were grown in the sand culture, and were applied with the solution containing both nitrate and ammonium as nitrogen source. pH of the solution was maintained at 4, 5, 6, 7, and 8, by frequent adjustments by adding HCI, or NaOH. After two years' growth, no significant differences in the growth and fruit yield (in the second year) were found among the vines growing at various pH ranging from 4 to 8.
In the second experiment, vines were grown in the solution culture. As nitrogen source, ammonium sulphate was applied to one series (ammonium series), and nitrate of soda to another series (nitrate series). The pH of the solution was maintained at 4, 5, 6, 7, and 8.
In the ammonium series, vine growth was normal at pH 6, 7, and 8, but was very poor at 4 and 5, and showed yellow spots in their leaves. In the nitrate series, growth was normal at pH 4 and 5, but leaves of the vines growing at higher pH became chiorotic, and failed early at pH 8.
Chemical analyses revealed that calcium and magnesium contents were low and iron content was very high at pH 4 and 5 in the ammonium series. In the nitrate series, calcium and, magnesium contents were high at lower pH, and iron content decreased significantly as pH increased.
