ISHS Acta Horticulturae 150: International Symposium on Substrates in Horticulture other than Soils In Situ
MARGINAL LEAF NECROSIS BY BORON EXCESS ON A TOMATO CROP CULTIVATED IN A SUBSTRATE OF POSIDONIA OCEANICA. (L.) DEL. POSSIBILITY OF CONTROL. |
| Author: | H. Verlodt |
| Abstract:
Composted 'Posidonia oceanica L.' seagrasses are very rich in Ca, Mg and B and very poor in K. Utilization of the pure substrate results in an imbalance of the K/B relation and about 2 months after planting marginal leaf necrosis is appearing in the eldest leaves of young tomato plants. Incorporation of well made stable manure permits to abtain higher levels of K resulting in a better K/B relation. A minimum incorporation of 10% stable manure prevented the apparition of marginal leaf necrosis, in spite of still high B levels in the substrate and the plant, and yield response was very interesting. Incorporation of marc of grapes has also a good effect on the potassium level and on the K/B balance, but has only small effects on the yield. Combination of 10% marc of grapes with 10% stable manure and 80% composted seagrasses gives better results. The volume of the growth bag seems also to have a positive effect on the element uptake and especially the K/B balance seems to be more favourable by use of growth bags of big volume. Reutilization of the substrate and yearly incorporation of 10 to 20 % well made stable manure results also in better K/B balances. | |
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