| Project/Area Number |
02045028
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | University-to-University Cooperative Research |
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| Research Institution | Ehime University |
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Principal Investigator |
KADOYA Kazuomi Ehime University. College of Agriculture. Professor, 農学部, 教授 (90036294)
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| Co-Investigator(Kenkyū-buntansha) |
任 振川 西南農業大学, 副教授
曽 明 西南農業大学, 講師
閻 玉章 西南農業大学, 副教授
李 道高 西南農業大学, 教授
MATUSMOTO Isao Ehime University. College of Agriculture. Assistant professor, 農学部, 助手 (70036325)
ISHII Takaaki Ehime University. College of Education. Associate Professor, 教育学部, 助教授 (30136296)
CHIKAIZUMI Sojiro Ehime University. College of Agriculture. Assistant Professor, 農学部, 助手 (90116955)
AMANO Shoji Ehime University. College of Agriculture. Assistant Professor, 農学部, 助手 (70116903)
HINO Akira Ehime University. College of Agriculture. Assistant Professor, 農学部, 助手 (10036353)
AKIYOSHI Hiroaki Ehime University. College of Agriculture. Assistant Professor, 農学部, 助手 (00036352)
WATANABE Junichiro Ehime University. College of Agriculture. Associate Professor, 農学部, 助教授 (10036311)
MIZUTANI Fusao Ehime University. College of Agriculture. Associate Professor, 農学部, 助教授 (20026595)
YAN Yuzhang Southwest Agricultural University. Associate Professor
LI Daogao Southwest Agricultural University. Professor
ZENG Ming Southwest Agricultural University. Lecturer
REN Zhenchuan Southwest Agricultural University. Associate Professor
曹 明 西南農業大学, 園芸系, 講師
閭 玉章 西南農業大学, 園芸系, 副教授
桜井 雄二 愛媛大学, 農学部, 助教授 (00036427)
鶴崎 孝 愛媛大学, 農学部, 教授 (50036323)
久守 藤男 愛媛大学, 農学部, 教授 (60024535)
佐藤 晃一 愛媛大学, 農学部, 教授 (70033149)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 1992: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1991: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1990: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Citrus / Sod culture / Soil erosion / Steep slope orchard / Bahiagrass / VA mycorrhizal fungi / Ethylene / 果樹 / 急傾斜地 / 果実の成熟生理 / 非クリマクテリック性 / カンキツの果皮障害 / ブドウの整枝法 / キウイフル-ツの台木 / 果樹のウイルス病 / 着色 / 貯蔵 |
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| Research Abstract |
Most of citrus orchards of western part of Japan are located on steep slope. Fifty percent or more acreage are located on the slope above 15ﾟ. Soil erosion is one of the most serious problems in those orchards.It has been reported that soil erosion reached an amount of 25.6t/ha/year in an orchard of clean culture. Precipitation of the year was 1224mm. By introducing sod culture, the followings can be expected. (1)Improvement of soil texture ; (2)Prevention of surface soil erosion ; (3)Organic matter supply as a source of humus and (4)Propagation of useful microorganisms.
Roost of bahiagrass penetrate into somewhat consolidated layer of the soil and make the soil porous. Decayed leaves of the grass are transformed into humus. On the root surface of bahiagrass, VA mycorrhizal fungi proliferates.It is observed that VA fungi population on the citrus roots (Poncirus trifoliata) is high where bahiagrass is introduced for sod culture. VA fungi may contribute to absorb phosphate by the citrus r
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oots from the soil where phosphate is scarce. Although sod culture had been introduced to commercial citrus orchards, it has not been successful in Japan. Citrus growers have believed the clean culture is the best for high grade fruit production. However, we are now on the stage when soil management must be fundamentally reconsidered.
Previously grasses introduced for sod culture was mainly originated in northern Europe. These grasses grow so vigorously from late March to April. Competition of nutrient absorption between citrus roots and the grass is very sever. It is very important to preserve spring cycle shoots for high yield. Because flower differentiation and fruit bearing are stable on those shoots. If the grass might depress the growth of spring cycle shoots, the significance of sod culture will be lost. To overcome the competition in the nutrient absorption, it becomes necessary to introduce grasses originated in tropical or subtropical regions. It has been reported that bahiagrass is recommended in the orchards of Taiwan. The grass becomes dormant from December to April in Japan. There is no problem of rhizosphere temperature as affected by the grass during the period from late March to April and the competition is not serious. The grass grows vigorously in summer. Herbicide treatments will be necessary. But the amount of herbicide for bahia grass control can be reduced to about one third compared with the miscellaneous weed control. In the future, growth retardants for bahiagrass might be developed and applied by overhead sprinkler system. Bahiagrass is weak at germination and is overcome by other species. So at present investigations are focussed on how to establish the species being dominant in the citrus orchards. Less
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