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Volume 44 (1999)
- Issue 4 Pages 285-
- Issue 3 Pages 163-
- Issue 2 Pages 115-
- Issue 1 Pages 1-
- Issue Suppl Pages 2-
Volume 44, Issue 1
Displaying 1-13 of 13 articles from this issue
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Hiroomi Asano, Katsunori Isobe, Yoshio Tsuboki1999 Volume 44 Issue 1 Pages 1-8
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSIn the Aigamo duck farming system, the effect of weeding depends on the sphere of action of Aigamo ducks. The eating habits of this duck and actions related to their weeding were researched, and the effect of weeding using Aigamo ducks evaluated. A survey of the gullets of the ducks showed a tendency to eat insects as well as weeds. This meant that letting the ducks loose would achieve not only the effect of weeding, but also the extermination of harmful insects. Aigamo ducks were vigorously active early in the morning and at dusk, and moved around freely in the paddy fields. A follow-up survey on one individual duck found the distance covered was 3.8km during the period from 3:00a.m.-20:00p.m. (17 hours) in a 20 a (56m×37m) paddy field. The loose period of ducks were usually settled between 40-50 days, from the end of June (3-4 weeks after transplanting of rice) to the beginning of August (heading date). Thus, the area covered during their active hours was adequate for weed control. P. thunbergii, P. hydropiper and S. juncoides remained in following the Aigamo ducks cultivation, but the weeding they achieved was great and was almost the same as that achieved using an herbicide. Weeds were controlled from a week after the ducks were let loose to the beginning of August.View full abstractDownload PDF (6443K) -
Md. Amzad Hossain, Yukio Ishimine, Hikaru Akamine, Seiichi Murayama, M ...1999 Volume 44 Issue 1 Pages 9-18
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSField experiments were conducted to evaluate torpedograss (TG) infestation in sugarcane fields with different days of weeding in plant sugarcane during 1994-1996 on Okinawa island. This experiment was done in both a plant and 1st ratoon sugarcane field on the same site. In the plant sugarcane field, no regrowth of TG was observed until final harvest when weeding was done 45 days after planting (DAP); regrowth observed, however, in the plots weeded at 60DAP or later. Decreasing yield of sugarcane was recognized as weeding was delayed; this decreased rate was recorded as 0.9-1.5% per day during 45-90DAP. In the plant sugarcane field, weeding at 45DAP provided a higher number of tillers and greater elongation of sugarcane stem (stalk), which ultimately resulted in significantly higher yield than late weeding. In the ratoon sugarcane period, no regrowth of TG was observed in the plots weeded at 45DAP, and this resulted in significantly higher yield than in late weeded plot. Around 10 times greater TG biomass was recorded from the 60DAP weeded fields in the ratoon sugarcane period than that in the plant sugarcane period. The yield of ratoon sugarcane of 60DAP or later weeded fields was half that of the weed free or 45DAP weeded field. Overall results indicate that torpedograss should be controlled within 45DAP in the plant sugarcane period for lower weed infestation and to obtain a higher yield in both plant and ratoon sugarcane on Okinawa island.View full abstractDownload PDF (1090K) -
Toshiyuki Ohtsuka, Masayuki Nemoto1999 Volume 44 Issue 1 Pages 19-28
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe effects of riverside eutrophication on plant growth were examined using Persicaria thunbergii, a typical annual species abundant in riverbanks in Japan. The ecological characteristics of this species were studied under three different conditions, viz. cultivated under experimental nutrient gardients in glasshouse, directly planted on riverbanks, and planted in pots and placed in streams. In the glasshouse, the biomass and leaf area of this species lineraly increased with increasing nutrient levels (Fig. 1). The relative growth rate (RGR) and leaf area ratio (LAR) also increased in a similar fashion, and RGR gained a maximum of 0.96mg mg-1 week-1, though the net assimilation rate (NAR) did not show any particular trend (Fig. 2). The higher LAR was attributed to the higher allocation ratios to the leaves (Fig. 3), which resulted in enhanced RGR at higher nutrient levels. Under field conditions, the biomass and top: root ratio of P. thunbergii planted on the riverbanks of mid- and lower streams were higher than those in the upper stream area devoid of eutrophication (Fig. 4, 6). Morphological indices (MI) of the plants grown in the mid-and lower streams were higher (MI>1) than those in the plants grown in the upper stream (MI<1), which may be due to horizontal expansion of the shoots of the plants grown at higher nutrient levels (Fig. 5). The individuals placed in the mid-and lower streams, however, died in some areas due to frequent flooding, and did not show any apparent growth response to nutrient levels. These findings indicated that P. thunbergii does not reach a normal growth under frequent flooding. It is concluded that the changes in biomass, leaf area and top: root ratio of P. thunbergii are quantitative features referred to nutrient levels except for the flooding conditions, and therefore this species can serve as an indicator plant to assess the effects of riverside eutrophication.View full abstractDownload PDF (1289K) -
Kangetsu Hirase, Daisuke Kishi, Sadafumi Koda1999 Volume 44 Issue 1 Pages 29-36
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSNaproanilide disappearance under flooded conditions was examined in three types of granules. The formulations tested were 2 kinds of 1kg granules and ordinary 3kg granules. One of the 1kg granules contains a floating carrier which enhances naproanilide release in water (1kg-A granule), and the other does not contain such a carrier (1kg-B granule). Naproanilide concentration in water applied with 1kg-A granules increased within 30min after application, whereas the concentration remained lower in the case of 1kg-B and 3kg granules. Half-life of naproanilide in soil to which these granules were applied was about 8 days, and there was no difference among them. Nor was any difference detected in the rate of naproanilide photolysis or microbial degradation in water among these granules. The herbicidal efficacy against Monochoria vaginalis Presl var. plantaginea Solms-Laub., however was different: that of 1kg-B granules was lower than those of 1kg-A and 3kg granules. The cause of the difference was investigated by checking naproanilide distribution on soil surface applied with 1kg-A and 1kg-B granules. Soil was sampled from two different areas: soil holding one granule and that holding no granules. Concentrations in the soil holding a granule were high enough to control the weeds in both types of 1kg granules, but concentrations in the soil holding no granules were low. In particular, that holding no granules was much lower in the case of 1kg-B. The lower concentration on soil surface holding no granules was thought to have caused the lower herbicidal efficacy of this formulation.View full abstractDownload PDF (938K) -
Kenji Usui, Fan Deng, Ie Sung Shim, Katsuichiro Kobayashi1999 Volume 44 Issue 1 Pages 37-42
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSContents of pretilachlor [2-chloro-2′, 6′-diethy1-N-(2-propoxyethyl)-acetanilide], fenclorim [4, 6-dichlor-2-phenylpyrimidine] and metabolites of the two chemicals in rice (Oryza sativa L. cv. Nipponbare) and early watergrass (Echinochloa oryzicola Vasing.) seedlings treated with pretilachlor alone or a combination of pretilachlor and fenclorim were examined in relation to selectivity and safener action. The contents of pretilachlor and a metabolite of fenclorim (GS-fenclorim) were lower in rice than in early watergrass seedlings, but the contents of fenclorim and metabolites of pretilachlor were higher in rice than in the watergrass. The results illustrated that selectivity of pretilachlor between rice and early watergrass might be strongly related to the content of pretilachlor and the detoxicative metabolisms, and the safening effect of fenclorim might also be related to the content of fenclorim and its metabolite in the two plants.View full abstractDownload PDF (702K) -
Kiwamu Fujita1999 Volume 44 Issue 1 Pages 43-50
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSEffect of soil application of several herbicides on the initial growth of shoots and roots in direct seeded rice seedlings sown at 0cm and 1cm depths under flooded paddy conditions was investigated.
1) Mild chlorosis or necrosis appeared in water-seeded rice seedlings after the application of pyrazolate, but subsequently the symptoms did not affect the growth. Phytotoxicity including inhibition of shoot elongation and tillering of rice seedlings appeared after the application of bensulfuron-methyl·dimepiperate, pyrazosulfuron-ethyl·etobenzanid and imazosulfuron·etobenzanid·dymron. The degree of inhibition was different depending on the sowing depth of rice and the types of herbicides applied. Phytotoxicity was more severe in the seedlings sown at 0cm depth than in those at 1cm depth.
2) Inhibition of elongation of crown roots in the root system, which was considered to occur after the application of sulfonylurea herbicides, was observed after the application of bensulfuron-methyl·dimepiperate, pyrazosulfuron-ethyl·etobenzanid and imazo·sulfuron·etobenzanid·dymron. The degree of inhibition was larger for the seedlings sown at 0cm depth than for those at 1cm depth. Severe impairment of crown root elongation resulted in floating or inverted seedlings when the sowing depth was 0cm.
3) Decrease of dry weight was not observed in the seedlings sown at 1cm depth except after pyrazosulfuron-ethyl·etobenzanid application, but was observed in the seedlings sown at 0cm depth and the degree was different depending on the types of herbicides applied.View full abstractDownload PDF (873K) -
Suthep Tongma, Katsuichiro Kobayashi, Kenji Usui1999 Volume 44 Issue 1 Pages 51-58
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSLaboratory experiments were conducted to determine the phytotoxic activity of water leachates from Mexican sunflower [Tithonia diversifolia (Hemsl.) A. Gray] leaves and the effect of water movement on efficacy of the leachate in soil. The water leachates from both the green and senescent leaves applied onto soil inhibited root growth of rice seedlings. The phytotoxicity of leaf leachate depended on the concentration of phytotoxic substances which was determined by the amount of leaves extracted. Mobility of phytotoxic substances from Mexican sunflower leaves in soil was dependent on water movement and soil moisture conditions. More downward movement was observed in dry soil than in wet soil. The inhibitory activity of water leachate in soil was well correlated with the concentration in soil-water. The allelopathic potential of Mexican sunflower leaves in natural field was discussed.View full abstractDownload PDF (1146K) -
Tomoko Nishida, Shunji Kurokawa, Shohei Shibata, Norihisa Kitahara1999 Volume 44 Issue 1 Pages 59-66
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSA study was conducted to determine the length of exposure to heat necessary to kill water-imbibing weed seeds at 55 and 60°C. The examination covered ten upland weed species: Solanum carolinense L., S. americanum Mill., Abutilon theophrasti Medic., Phytolacca americana L., Amaranthus spinosus L., A. patulus Bertoloni, Persicaria lapathifolia (L.) S. F. Gray, Panicum dichotomiflorum Michx, Echinochloa crus-galli (L.) Beauv. var. crus-galli and Digitaria ciliaris (Retz.) Koeler. All seeds of each species were killed by exposure to heat at 55°C for 72hr and at 60°C for 24hr except for those of Abutilon theophrasti (dormant seed rate 80%) which were killed by exposure for 120 and 30hr at the respective temeratures.
These weed species fell into four groups, categorized by a combination of short-duration heat-tolerance (SDHT) and long-duration heat-tolerance (LDHT). SDHT was determined by the viability of weed seeds when treated at 60°C for 3hr, with low and high subcategories of tolerance. LDHT was detemined by the duration required to kill all the seeds at 1% level of significance when treated at 60°C, into three subcategories (low, medium and high tolerance). Persicaria lapathifolia, E. crus-galli, and D. ciliaris were low for both SDHT and LDHT (Group I), and Amaranthus spinosus and Panicum dichotomiflorum were low-SDHT and medium-LDHT (Group II). Solanum species, Phytolacca americana, and Amaranthus patulus were high-SDHT and medium-LDHT (Group III), while Abutilon theophrasti was low-SDHT and high-LDHT (Group IV). The viability of seeds at short-duration heat treatment for Group I, II and IV was low, but the durations required to kill all seeds were different among the groups. Group III consisted of species for which the viability of seeds at short-duration heat treatment was high, and the fatal duration was medium.
For Abutilon teophrasti which required the longest duration of heat exposure to kill all seeds at each temperature, 95% confidence intervals of LD90 values were calculated using the probit method, and were 42 to 58 and 10 to 17hr at 55 and 60°C, respectively.View full abstractDownload PDF (1035K) -
Mototsugu Yanagida, Hiroshi Matsumoto, Kenji Usui1999 Volume 44 Issue 1 Pages 67-76
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSTo further investigate the role of antioxidative systems in plant tolerance to diphenylether (DPE) herbicides, the relationship between the antioxidative enzyme activities, antioxidant content and the level of oxidative damage by oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-trifluoromethyl benzene] were investigated in rice, corn, radish and buckwheat. Rice showed the highest tolerance to oxyfluorfen, while buckwheat showed the lowest. However, both plants accumulated a larger amount of protoporphyrin IX (Proto IX) than corn or radish which showed intermediate tolerance to the herbicide. The measurement of antioxidative enzymes, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APx) and glutathione reductase (GR), and antioxidant contents of carotenoids and reduced glutathione (GSH) in four plants showed that SOD and CAT activities and GSH content were much higher in rice than in the other plants. Furthermore, activities of all the enzymes in rice were increased until Proto IX accumulation reached maximum (4hr after light irradiation). The antioxidative ability of buckwheat was lowest and was not increased by the herbicide treatment at all. The results strongly suggested that antioxidative ability is one of the critical factors determining the tolerance to oxyflourfen in some plant species.View full abstractDownload PDF (1143K) -
Ryuichi Sago, Ryota Yoshimoto, Shigeru Takayanagi, Teruo Matsuda1999 Volume 44 Issue 1 Pages 77-79
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (407K) -
Mitsuyoshi Suzuki1999 Volume 44 Issue 1 Pages 80-83
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (433K) -
questionnairemethodSeok Weon Seo1999 Volume 44 Issue 1 Pages 84-87
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (461K) -
Ie-sung Shim, Reiichi Miura, Etsuko Ishikawa, Masaaki Tachibana, Akira ...1999 Volume 44 Issue 1 Pages 92-99
Published: April 30, 1999
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (1111K)
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