ウンシュウミカンの発芽期前後における葉面散布尿素の吸収・移行 : 散布回数とマシン油混用の影響(土壌管理・施肥・灌水)  [in Japanese] Absorption and Translocation of Foliar Applied Urea in Satsuma Mandarin during the Sprouting Stage : Effect of Number of Applications and of the Combination with Petroleum Oil Emulsion(Soil Management, Fertilization & Irrigation)  [in Japanese]

ウンシュウミカン樹において発芽期前後に葉面散布された尿素の吸収・移行特性を明らかにするため,^<15>Nトレーサー法を用いて2か年間の圃場試験とポット試験を行った.マシン油乳剤との混用の有無に関わらず,葉面散布された尿素は3月下旬においても旧葉から吸収され,6月中旬までにその57%が春季新生器官に移行した.ただし,根部への移行量は極めて少なかった.葉面散布された尿素の吸収量は,少なくとも3回散布までは散布回数に比例して増加し,その利用率は散布窒素量の約40%前後であった.これらのことから,3月下旬〜4月上旬の尿素葉面散布は,窒素レベルが低下している樹に対して全窒素を増加させる効果があることが示された.

The absorption and translocation of urea applied to the foliage of satsuma mandarin at the sprouting stage was monitored for two years using the ^<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.