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Volume 40 (1995 - 199･･･
- Issue 4 Pages 245-
- Issue 3 Pages 157-
- Issue 2 Pages 69-
- Issue 1 Pages 1-
- Issue SupplI Pages 2-
Volume 40, Issue 1
Displaying 1-9 of 9 articles from this issue
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Yusuke Fukushima, Mitsuyoshi Ohkuma, Kohei Tanaka1995 Volume 40 Issue 1 Pages 1-7
Published: May 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSWeed emergence in early-season paddy-rice culture was compared with that in normal-season culture in northern Kyushu. Efficacy of several herbicides applied at different times was also investigated.
1) The emergence of weeds such as Monochoria vaginalis (Burm. f.) Kunth, Lindernia procumbens (Krock.) Borbas, Scirpus juncoides Roxb. var. ohwianus T. Koyama and Echinochloa oryzicola Vasing.) was slower in early-season culture than in normal-season culture. Among these species, in particular M. vaginalis and L. procumbens emerged late and yearly differences in the onset of emergence were large (Fig. 1).
2) It was suggested that the period during which weeds should be controlled was longer in early-season culture than in normal-season culture, because yearly differences in the date of emergence of 40-50% and of 100% of total weeds were large and also weeds emerged after midseason drainage in early-season culture (Fig. 1).
3) In early-season culture, all the herbicides controlled weeds more effectively with in 12 days than 5 days after transplanting, especially, in the sandy loam field (Fig. 2).View full abstractDownload PDF (733K) -
Ryuichi Sago, Masakazu Komatsuzaki1995 Volume 40 Issue 1 Pages 8-13
Published: May 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSMore than 30 years have passed since a herbicide effective for annual weeds was used to control weeds in Japan. However changes in the weed seed density in soils of paddy fields have not been clarified under successive herbicide applications. We analysed the seed density in soil during a period of 12 years in rice fields in Kanagawa prefecture where rice plants had been cultivated for more than 70 years and treated with herbicides for at least 30 years. The number of weed seeds was estimated based on the number of seedlings emerging from paddy soil samples collected from paddy fields. The soil samples were kept in shallow pots with water at a depth of 1cm in a green house without controlled temperature. Seedlings were identified, counted and removed periodically thoroughout the germination period. Emerged species included Lindernia procumbens (Krock.) Borbas., Elatine triandra Schk. var. japonicus Miq. ex Maxim., Rotala indica (Willd.) Koehne var. uliginosa (Miq.) Koehnne, Cyperus difformis L., Ammannia multiflora Roxb. and Monochoria vaginalis (Burm. f.) Presl var. plantaginea (Roxb.) Solms-Laub. Weed seed density in soil including 6 species ranged from 2, 264 to 10, 650per m2 among 9 plots in 1982. The weed seed density in soil was reduced from the above numbers in 1982 to 354-1, 847per m2 in 1994. The overall decline in the total number of weed seeds was 78.0% where herbicides had been applied every year. The decrease in the number of weed seeds in soil was ascribed to the fact that the reproduction of weed seeds was minimized during the 12 year period of herbicide application. The results on weed seedbank in relation to herbicide application may contribute to the development of a profitable and efficient weed management system.View full abstractDownload PDF (598K) -
Hisako Shioya, Hirokazu Tsubura, Hiroshi Tanaka, Kosumi Yamada, Toyoak ...1995 Volume 40 Issue 1 Pages 14-19
Published: May 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe growth-promoting activity of the exudates from of various plant species was compared with that of their ashes in the Amaranthus hypocotyl elongation test. Changes in the activity by the burning of exudates were markedly different among plant species (Fig. 1). Based on the effect of burning, tested plants were classified into three type;
(a) The ashes showed a loss or decrease of the activity (Cyperus iria, Amaranthus viridis, Amaranthus lividus, Chenopodium album, Amaranthus caudatus, Veronica persica, Latuca sativa, Petroselinum crispum, Cryptotaenia japonica, Daucus carota, Echinochloa crus-galli, Allium tuberosum, Spinacia oleracea, Oryza sativa).
(b) The ashes showed a much greater activity than the exudates (Cucurbita moschata).
(c) The promoting activity of the exudates was not affected by the burning (Lepidium sativum, Brassica oleracea, Archtium lappa, Asparagus officinalis, Fagopyrum esculentum, Helianthus annuus, Avena sativa, Abelmoschus esculentus, Pisum sativum).
The relationship between the growth-promoting activity of the exudates or the ashes and seed weight was examined in various plant species. The activity of the ashes showed a positive correlation with the seed weight (r=0.83), unlike that of the exudates (r=0.66) (Fig. 2).
These results suggest that inorganic substances as well as organic substances such as lepidimoide act as growth-promoting factors in the exudates from plant seeds. The organic substances may be physiologically released from seeds, whereas inorganic substances may be released physically.View full abstractDownload PDF (701K) -
Motoaki Asai, Misako Ito, Tokuichi Kusanagi1995 Volume 40 Issue 1 Pages 20-28
Published: May 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSMaintainable clover cover is a desirable vegetation for suppression of noxious weeds. The effects of seeding times and rates of white clover (Trifolium repens L.) on the development of its stands, and on the weed populations therein were determined by a 2-year factorial experiment. Two cultivars (cv. Grasslands Huia, and cv. California Ladino), 2 seeding times (mid-September and mid-October) and 2 seeding rates (2.0kg/10a and 0.5kg/10a) were compared. In all treatment plots, clovers germinated and developed successfully. Early (September) seeding was more effective and dense (2.0kg/10a) seeding was also an important factor for establishing a good clover cover. Completion of clover cover was delayed most in the late (October) and sparsely (0.5kg/10a) seeded plots. Delayed completion of the clover cover allowed the invasion and/or emergence of winter annual weeds, especially Capsella bursa-pastoris and Erigeron sumatrensis. These annuals had little effect on clover dominance, although the plants of E. sumatrensis grew tall, suppressed under-growth of clover and presented unsightly stands when they were not mown. E. sumatrensis regrew after April mowing, but died after June mowing. Invasion of Rumex spp. and Lolium multiflorum was not prevented by the early completion of clover cover. Influences of seeding methods lasted through 1992, but dissipated in 1993. ‘Ladino’ maintained taller plant height and better continuous coverage than ‘Common’.View full abstractDownload PDF (968K) -
Shinichi Shirakura, Kenji Ito, Stephen K. Gee, Aldos C. Barefoot, Hiro ...1995 Volume 40 Issue 1 Pages 29-38
Published: May 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSAzimsulfuron (DPX-A8947) is one of sulfonylurea herbicides developed by E. I. du Pont de Nemours and Co. Inc. as a paddy rice herbicide. Azimsulfuron is also an acetolactate synthase (ALS) inhibitor. Results of greenhouse pot tests indicated that azimsulfuron at a rate as low as 6g a. i./ha affords excellent control of sedge and perennial weeds, whereas a higher rate is required to give excellent control on annual broad leaf weeds. Especially activity of Cyperus serotinus and Eleochalis kuroguwai was significantly higher than that of bensulfuronmethyl (BSM). Azimsulfuron afforded a comparable rice safety to that of BSM at 75g a. i./ha up to 12g a. i./ha under the tested conditions. Data from glass tube studies, in which plants were directly exposed to chemicals, suggest that the high selectivity between rice and Cyperus serotinus may mainly be attributed to physiological or biochemical factors in plants as in the case of BSM which is rapidly metabolized in rice plants. In greenhouse studies, a mixture of azimsulfuron with BSM was found to be effective. Addition of azimsulfuron significantly improved the activity of BSM on perennial sedges without causing rice injury and reduced the total quantity of chemicals used. This combination controlled the tested weeds well even under environmental factors such as water leaching, overflow of paddy water and low temperature. The results obtained suggest that azimsulfuron is a promising rice herbicide especially in combination with BSM in terms of high biological activity and rice safety.View full abstractDownload PDF (901K) -
Yuji Yamasue, Robert A. Kennedy, Tokuichi Kusanagi1995 Volume 40 Issue 1 Pages 39-43
Published: May 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSFlooding tolerant and intolerant varieties of Echinochloa crus-galli (Linn.) Beauv. at spikelet germination were studied to determine the oxygen requirement of their fruit germination. Detached fruits of the tolerant and intolerant varieties, formosensis Ohwi and praticola Ohwi, respectively, were found to be able to germinate under flooding or nitrogen atmosphere. However, fruit germination of the intolerant variety was inhibited when the highly lignified second floral lemma were added back to the imbibition medium either under nitrogen or under air along with an antioxidant, dithiothreitol. These results suggest that the floral lemma of praticola contain an agent (s) which inhibits fruit germination under a reduced state, but is readily inactivated by oxidation.View full abstractDownload PDF (527K) -
Motoaki Asai, Misako Ito1995 Volume 40 Issue 1 Pages 44-46
Published: May 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (322K) -
Nobumasa Ichizen, Hitoshi Kuramochi, Makoto Konnai, Haruki Innami, Sat ...1995 Volume 40 Issue 1 Pages 47-49
Published: May 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (290K) -
Hiroshi Matsumoto, Tohru Tominaga, Tadashi Sumiyoshi, Masaaki Tachiban ...1995 Volume 40 Issue 1 Pages 52-57
Published: May 31, 1995
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (795K)
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