日本柑桔栽培之見聞

Citriculture in Japan Today

美國夏威夷大學東西文化中心召開之國際柑桔技術交換研究會議於五十四年（一九六五）十一月間在日本舉行，筆者等奉派出席會後順道考察日本主要柑桔產區。目前日本柑桔之單位面積產量極高，實屬驚人，就筆者等目睹一般柑樹每株均達120餘公斤以上者實到處皆是，管理之周密及病蟲害防治之徹底皆非本省果園所可比擬。目前臺灣柑桔產量平均每株僅十餘公斤，相差之大可以想見。有見於日本柑桔事業的若干措置可供本省今後桔產量平均每株僅十餘公斤，相差之大可以想見。有見於日本柑桔事業的若干措置可供本省今後改進之借鏡，今以「日本柑桔栽培之見聞」為題，簡述如次籍供有關人士之參考。

1.Japan's modified mother-tree orchards established at various research stations are very impressive indeed. Selections and clones planted at reduced spacing have rendered an efficient management possible. As a result of reduced spacing the amount of propagation materials produced per unit area of land have been much more than those from the conventional mother-tree orchards. The intensive and modified mother-tree orchards developed in Japan are:as a matter of fact the backbone of modern citrus industry. 2.Intensive windbreaks and perfect mulching observed at various citrus­producing centers are regarded as very effective means for promoting both tree development and dependable high yield. In a field trip to the centers, annual pruning of windbreaks to ensure better fruit production was observed. In one prefecture 80f6 of the orange orchards resort to mulching to effectively control soil erosion. The nationwide average indicated that mulching is practised by 38% of the orange orchards. 3.Fruit thinning, pot-culture and rootstock studies are the common practices of farmers'orchards and experimental stations. We have found that fruit thinning is effective in regulating annual production; the pot culture, an ideal way to study citriculture on limited land, is desirable for conducting different phases of studies with special reference to the controlled soil conditions under which the behavior of root growth as well as the top­response could be efficiently studied. The rootstock studies conducted at experimental stations for a number of years provided us with valuable information on the yield, quality and maturity of new varieties which have contributed greatly to the development of the citrus industry in Japan.