New Systems and Technologies for High Quality Citrus Fruit Production, Labor Saving
and Orchard Conservation in Mountainous Areas of Western Japan
Kunihisa MORINAGA
National Agricultural Research Center for Western Region, NARO
Zentsuji, Kagawa, 765-0053 JAPAN e-mail: forest@affrc.go.jp
ABSTRACT
Citrus cultivation has been one of the most important industries in mountainous areas of western Japan
because of well drainage and abundant sunshine in spite of topographic disadvantage conditions. However,
novel technologies such as mechanized system have been required to improve fruit quality and productivity,
and laborsaving since aging of growers and decrease of successor are remarkable in recent years. In
addition, orchards conservation on steep sloping lands is also required.
The purpose of this paper is to introduce new systems and technologies which have been researched and
developed for high quality fruit production, laborsaving and land conservation in steep lands, (1) the drip
irrigation and liquid fertilizing system combined with year-round plastic mulching, (2) new transporting
system using contour narrow paths combination of monorail system, and (3) disaster prevention mapping
for citrus orchards.
New fruit quality control system using drip irrigation and liquid fertilization technique combined
with year-round plastic mulching was developed, expecting high quality and stable fruit production
of citrus. Moisture-permeable plastic mulching sheets are covered under citrus trees. Water and/or
nutrient solution is automatically supplied through the drip tubes that are laid under the mulching
sheets to give adequate water stress to improve sugar and acid content of fruit. Fruit quality was
controlled well through the system, e.g. it raised 20-30% of sugar content. This is reflected in
grower’s income. Furthermore, laborsaving effect of water and fertilization management was
observed. Extensive studies regarding to efficient irrigation time and appropriate amount of water or
nutritional solution have been conducted.
New transporting system for steep sloping citrus orchard, which is the combination of monorail system and
contour narrow paths, was suggested. To excavate narrow paths, the utilization of a small waking tractor
was developed and the procedure of narrow path excavation was explained. The efficiency of excavation
using the walking-tractor was 20-57 m/h from the investigation in four different steep sloping orchards. To
evaluate the improvement effect of growers work by narrow path, the time study survey of main
management works of citrus orchard was conducted. After introducing narrow path, the working hours was
reduced in the fertilizer and the chemical herbicide application. The working space and the leveled ground
provide by narrow path realized the safely work without fal1ing down for all works.
Disaster prevention mapping of citrus orchards on slope lands was developed based on computer-aided
seepage estimation and topographic data. The mapping can show the both zones of ascending flow (upward
seepage flow) and descending flow (downward seepage flow) of under ground water on heavy rain in citrus
orchards. The mapping is considered to be effective for the management of orchards and prevention from
erosion on slope lands. Multi-purpose and high-functional farm path foundation on ascending flow area of
orchard was efficient for the ability of disaster prevention.