Absorption and translocation of foliar applied urea in satsuma mandarin [Citrus unshiu] during the sprouting stage: Effect of number of applications and of the combination with petroleum oil emulsion
2008
Ishikawa, K.(Ehime-ken. Fruit Tree Experiment Station, Matsuyama (Japan)) | Kimura, H. | Yoshikawa, S.
The absorption and translocation of urea applied to the foliage of satsuma mandarin at the sprouting stage was monitored for two years using the sup(15)N-tracer method in potted and field-planted trees. Urea applied to foliage even in late March was absorbed into old leaves, regardless of combination with or without petroleum oil emulsion. Of the urea absorbed, 57% moved to newly developed organs until mid-June and almost none moved to the roots. The absorbance of urea applied to the foliage increased with the number of applications up to at least three-fold and about forty percent of the applied the amount was absorbed. These finding's suggest that urea applied in late March or early April effectively increases nitrogen level of trees with nitrogen deficiency.
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