Abstract
Several instances of nutritent deficiency of grapevines occurred in vineyards of Osaka prefecture were collected for investigation.
The information obtained from these instances are found to be useful for nutritional diagnosis of plant and soil test.
The results were as follows.
1) Magnesium deficiency: Under greenhouse conditions leaf Mg contents of ‘Delaware’ and ‘Kyoho’ grapes showing Mg deficiency symptoms were less than 0.09% and 0.12%, respectively. Exchangeable Mg content in the vineyard soil of ‘Delaware’ was less than 13 mg/100 g. Such a low level of exchangeable Mg was obviously insufficient for healthy growth of ‘Dela-ware’ grape. On the contrary, Mg deficiency symptom was observed on the leaves of ‘Kyoho’ grapes growing in the soil having exchangeable Mg as high as 50 mg.
2) When Mn concentration in the leaves was less than 21 ppm, the interveinal tissue turned light green and the berries had poor coloration.
The pH (H2O) of such a soil was nearly 7.0 and exchangeable Mn was less than 3 ppm. Mn deficiency symptom was markedly decreased by foliar application of 0.4% MnSO4 solution. The effect was greater when applied after anthesis rather than before it.
3) Boron deficiency : When leaf B concentration was 7-13 ppm, boron deficiency symptom was found on younger leaves and inside of berries.
