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Volume 46 (2001)
- Issue 4 Pages 261-
- Issue 3 Pages 169-
- Issue 2 Pages 91-
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Volume 46, Issue 1
Displaying 1-11 of 11 articles from this issue
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Hideo Chisaka2001 Volume 46 Issue 1 Pages 3-4
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
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Akira Koarai, Hidejiro Shibayama2001 Volume 46 Issue 1 Pages 5-12
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSSeasonal changes in the number and depth of emergence of annual weeds were investigated in paddy soil, as the weeds were severely infesting Japanese paddy fields, occasionally even after the application of herbicides. Emergence pattern and depths were determined for seedlings of Monochoria vaginalis, Lindernia procumbens, Elatine triandra var. pedicellata, Ammannia multiflora, Rotala indica var. uliginosa and Cyperus difformis in paddy soils, which were puddled and leveled in the middle of April, May, June and July in 1990 at Tsukuba, Ibaraki Pref., central Japan. The number of emerged seedlings increased as the puddling time was delayed from April to June for M. vaginalis, L. procumbens, E. triandra and R. indica var. uliginosa, and to July for A. multiflora and C. difformis (Table 1). Almost all of these species emerged within two weeks after puddling, throughout four puddling times (Fig. 1). Emergence depth of the seedlings determined by the length of their underground parts generally corresponded to the soil layers located within 5.0mm from the surface (Fig. 3). Seedlings seldom emerged in the soil layers within a 5.0 to 7.0mm depth from the surface. C. difformis emerged at a higher depth than the other species. The number of emerged seedlings in the soil layers within 3.0mm from the surface increased with the delay in the puddling time. However, the number of emerged seedlings in the soil layers located at a depth of more than 3.0mm from the surface and the maximum emergence depth were constant when puddling time was delayed.View full abstractDownload PDF (861K) -
Hiroomi Asano2001 Volume 46 Issue 1 Pages 13-18
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSWeed emergence for both an aigamo duck farming system and an ordinary farming system using herbicides in paddy fields for 3 years was investigated in Aikawa town, Kanagawa prefecture. Fourteen weed species were identified in the soil surface layers: Echinochloa spp., Monochoria vaginalis (Burm. f.) Presl var. plantaginea (Roxb.) Solms-Laub, Lindernia spp, Eleocharis acicularis (L.) Roem. et Schult., Elatine triandra Schk. var. pedicellata Krylov, Rotala indica (Willd.) Koehne var. uliginosa (Miq.) Koehne, Cyperus spp., Ludwigia epilobioides Maxim., Ammannia multiflora Roxd., Dopatrium junceum (Roxb.) Hamilt., Scirpus juncoides Roxd. var. ohwianus T. Koyama, Sagittaria trifolia L., Oenanthe javanica (Blume) DE. and Cardamine flexuosa With.
In the aigamo duck farming system, weed emergence from the soil surface layers was very low at 0-2cm depth of the outer layer while it was high at the same deeth in the ordinary farming system using herbicides. This is because in the Aigamo duck farming system, the duration of the period of weed control (40-70 days) was 2 or 3 times longer than in the ordinary system using herbicides. The aigamo duck farming system showed a low weed emergence subsequently. In the 2-10cm soil outer layer, there was no appreciable difference between the weed emergence in the two systems. For the 2-10cm soil outer layer, there was no difference between the weed emergence from the soil surface layers in the two systems (Table 2). The emergence of M. Vaginalis, R. indica and E. triandra decreased with continuous aigamo duck farming, while that of L. epilobioides and A. multiflora increased year by year and they became the major species (Figs. 1, 2, Table 2). Based in studies cmducted in 1994 and 1995, compared to the ordinary farming system use of herbicides, the aigamo duck farming system led to a lower weed emergence from the soil surface layers. However, in 1996, due to the predominance of L. epiloboiides, A. multiflora, Cyperus spp. and Dopatrium junceum (Roxb.) Hamilt. in the aigamo duck farming system, the total number of weeds which emerged increased, compared with the ordinary farming system (Fig. 3).View full abstractDownload PDF (632K) -
Hiroomi Asano, Tsutomu Kanehira, Katsunori Isobe2001 Volume 46 Issue 1 Pages 19-24
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSIn a paddy field in which Aigamo duck farming had been carried out for 1 to 8 years, the dominant specieas and the number of weeds which emerged were investigated. Fourteen weed species were identified: Echinochloa spp. Cyperus spp. Monochoria vaginalis (Burm. f.) Presl var. plantaginea (Roxb.) Solms-Laub, Lindernia spp., Dopatrium junceum (Roxd.) Hamilt., Rotala indica (Willd.) Koehne var. uliginosa (Miq.) Koehne, Elatine triandra Schk. var. pedicellta Krylov, Ludwigia epilobioides Maxim., Ammannia multiflora Roxb., Eclipta prostrata (L.) L., Eriocaulon sieboldtianum Sieb. et Zucc., Rotala leptopetala (Blume) Koehne var. littorea (Miq.) Koehne), Fimbristylis miliacea (L.) Vahl, Sagittaria pygmaea Miq. The order of the average major species identified in the same Aigamo duck farming system for 1 to 8 years was: Lindernia spp. (845/m2), E. triandra (515/m2), R. indica (480/m2), Cyperus spp. (240/m2), M. vaginalis (66/m2) (Fig. 1). The emergence of the major species did not vary with continuous Aigamo duck farming for 1 to 8 years. In the use of Aigamo duck farming for 1 to 4 years, the total number of weed that emergenced from the paddy field soil was 2, 857-2, 401/m2, whereas the number in the ordinary farming system use of herbicides was 2, 296/m2. In the same way, for 5 to 7 years, the number was 1, 123-1, 608/m2, corresponding to a 49-70% decrease compared with ordinary farming (Fig. 4). This experiment indicated that if Aigamo duck farming were to be performed with appropriate water management, fewer weeds would emerge than in ordinary farming.View full abstractDownload PDF (677K) -
Mitsuru Kanzaki, Masaki Takeuchi, Norio Shirakawa2001 Volume 46 Issue 1 Pages 25-30
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSFactors influencing the herbicidal activity of cafenstrole (N, N-diethyl-3-mesitylsulfonyl-1H-1, 2, 4-triazole-1-carboxamide) against Echinochloa oryzicola Vasing in paddy fields were investigated in a greenhouse. The herbicidal activity of cafenstrole (1-3g a. i./a) against the plant was not affected by the temperature (Fig. 1), the soil type (Fig. 2), the flooding water depth in the range of 1-6cm (Fig. 3) or water leakage (Fig. 4). The activity of cafenstrole, however, decreased in the absence of flooding water (Fig. 3), and when the drainage time after application and the duration of dipping of Echinochloa oryzicola Vasing plants was less than 12hrs respectively, at the 2.5 leaf stage (Fig. 5, 6).
In conclusion, the flooding water depth and the period of exposure to cafenstrole could be important factors affecting the herbicidal activity. In particular, the management of the flooding water is the most important factor for obtaining a high herbicidal activity of cafenstrole.View full abstractDownload PDF (615K) -
Hiroomi Asano2001 Volume 46 Issue 1 Pages 31-36
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSAsynchronous emergence of seedlings is a problem in the management of paddy field weeds. This phenomenon is caused by the heterogeneous germination characteristics of buried seeds and non-uniform environmental factors affecting them. To identify the environmental factors associated with asynchronous weed emergence, the influence of shading was investigated in paddy fields.
1. The overall number of weed seedlings decreased with the increase in the shading rate. The numbers of emerging plants in each weed species also decreased. In Ammannia multiflora Roxb., the correlation between the shading rate and emergence number was especially high: the coefficient of correlation was -0.985** (Table 1)
2. After the end of the shading treatment, 852/m2 weed plants emerged in the plot with 0% shading. The lower the emergence during the shading period, the higher the post-shading emergence. The higher total emergence, 1, 705/m2, was obtained in the 0% shading plot. Besides, the difference between the total amounts for 0-40% shading plots and 81-100% shading plots was significant at 5% according to Turkey's test (Fig. 2).
3. In A. multiflora Roxd., when the shading was severe, then was a high seedling emergence after shading, which was statistically confirmed by Tukey's test at 5% for 0-94% shading. The coefficient of correlation between the shading rate and emergence number for post-shading was 0.847** (Table 2).
4. Shading strongly affected the emergence of Lindernia procumbens (Krock.) Borbas, Ludwigia epilobioides Maxim., Elatine triandra Scjk. var. pedicelata Krylov., Rotala indica (Willd.) Koehne var. uliginosa (Miq.) Koehne, Cyperus difformis L., Ammannia multiflora Roxd., and Dopatrium junceum (Roxd.) Hamilt.View full abstractDownload PDF (642K) -
Ryuichi Sago, R. Matsuura, T. Matsuda2001 Volume 46 Issue 1 Pages 37-40
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
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Seturo Sato, Koji Tateno, Ryoji Kobayashi2001 Volume 46 Issue 1 Pages 41-47
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
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Hisayuki MAENAKA2001 Volume 46 Issue 1 Pages 48-55
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
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Hiroshi HAGIMOTO2001 Volume 46 Issue 1 Pages 56-59
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
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Yukari Sunohara, Masatoshi Gohara, Reiichi Miura, Shizuko Ishikawa, Ma ...2001 Volume 46 Issue 1 Pages 60-65
Published: March 30, 2001
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (721K)
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