Effect of NPK [nitrogen, phosphorus, potassium] fertilization and application of some soil amendment agents on. 4.- Preharvest fruit drop and the force needed to detach fruits from its pedicels as related to leaf Ca content of Valencia and Washington orange trees.
1989
Zayan M.A. | Morsy E.S. | El Hamady M.A. | Dawood S.A.
Fruit drop was significantly decreased by the higher level of nitrogen (1200 gm/ tree). Adding gypsum or sulfur to (N3+P+K) treatment, caused a significant reduction in fruit drop of "Valencia" and "Washington" Navel oranges. The force needed to detach fruits (F.N.D.F.) from pedicels, was markedly increased by adding gypsum or sulfur to all (N3+P+K) treatments. Application of gypsum or sulfur, led to a significant increase in leaf Ca concentration, as a result, the (F.N.F.D.) values were increased and fruit drop was markedly reduced in both varieties. The highest the leaf Ca content the greatest was the (F.N.F.D.) values.
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