All issues
Volume 42 (1997 - 199･･･
- Issue 4 Pages 307-
- Issue 3 Pages 189-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
- Issue Suppl Pages 2-
Volume 42, Issue 2
Displaying 1-14 of 14 articles from this issue
- |<
- <
- 1
- >
- >|
-
Katsuichiro Kobayashi1997 Volume 42 Issue 2 Pages 57-64
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (2430K) -
Shinichi Shirakura1997 Volume 42 Issue 2 Pages 65-72
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (667K) -
Shinya Umemoto, Hirofumi Yamaguchi1997 Volume 42 Issue 2 Pages 73-80
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSIn order to characterize the productivity of traditional Japanese paddy levees, seasonal changes in dry matter production of monocot, dicot, and others plants were investigated.
Based on the seasonal pattern of dry matter production in a plant community on paddy levees, four production types were recognized (Fig. 1 and Table 1): the sustainable type; the decreasing type; the increasing type; the unstable type. Most of the traditional paddy levee types, for example, the Kansai type and the Kuronashi type, belong to the sustainable type of dry matter production. Increase of dicotyledonous ratio (DR, %) in spring, decrease in summer, and minimal increase in autumn were usually observed in most of the paddy levees (Fig. 1). This pattern is considered to play an important role in the aesthetic landscaping of traditional paddy levees.
The paddy levees belonging to the Kansai and Kuronashi types are assumed to be suitable in terms of the multi-function and complexity of vegetation, and they may contribute to the on situ conservation of plant resources and play a role in the maintenance of cultural traditions.View full abstractDownload PDF (860K) -
Takuya Mineta, Yoko Oki1997 Volume 42 Issue 2 Pages 81-87
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSThe composition and density of buried seeds in an arable field reflect the past and present weed management and cultural practices in that field, as well as the types of crops grown. We observed seed banks in eight paddy fields located in the southern part of Okayama prefecture under different weed control methods and cultural practices (Fig. 1, Table 1). The soils containing seeds were collected from four layers at 0-5, 5-10, 10-15 and 15-20cm depths from the ground surface level. Seeds in each sample were extracted by the chemical flotation method using a 50% potassium carbonate solution.
Comparison of eight types of cultivation methods showed that the density of buried seeds was lowest in the case of successive herbicide treatments without tillage, followed by the same herbicide treatments to complement conventional tillage and in organic fields subjected to hand-weeding (Fig. 2). In contrast, the density of buried seeds increased, especially the seed population of Echinochloa, in fallow fields or fields with extensive cultivation. No-tillage cultivation resulted in the highest proportion of seeds in the surface layer, whereas in most of the ploughing methods seeds tended to be concentrated at a depth of 15 to 20cm (Fig. 3). The number of buried seeds of Monochoria vaginalis Presl var. Plantaginea Solms-Laub. and Heteranthera limosa Willd. tended to increase in organic fields that were not subjected to chemical control of weeds. On the other hand, winter weeds, such as Alopecurus aequalis Sobol. var. Amurensis Ohwi were major contributors to seed banks in fields where barley or Astragalus sinicus L. were grown in winter under reduced tillage conditions, in comparison with single cropping systems of rice.
The chemical flotation method using a potassium carbonate solution was effective to estimate seed banks in paddy fields, since the density of seeds in this method was correlated with the number of seeds of weed species determined by the seedling emergence method (Fig. 4).View full abstractDownload PDF (842K) -
Takuya Mineta, Kazumasa Hidaka, Takashi Enomoto, Yoko Oki1997 Volume 42 Issue 2 Pages 88-96
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSChanges in the Astragalus sinicus L. community, density of lowland weeds and rice grain yield were investigated in two adjacent direct-seeded paddy fields under A. sinicus living mulch and no-tillage cultivation without the use of pesticides and fertilizer during three years. In the first year of cultivation, A. sinicus community in both paddy fields grew thickly and few winter weeds occurred in the mulch community. However in the second or third year, the population of other species, such as Alopecurus aequalis Sobol. var. Amurensis (Komar.) Ohwi, Geranium carolinianum L., Stellaria alsine Grimm. var. Undulata (Thunb.) Ohwi increased along with the decline of the A. sinicus community (Table 1, Fig. 1). Althought the density of summer weeds after flooding was reduced in comparison with conventional culture in the first year, the density of weeds remarkably increased, particularly Echinochloa in the second year (Fig. 2). The population of perennial weeds, such as Rumex crispus L. ssp. japonicus (Houtt.) Kitam. and Ranunculus cantoniensis DC. ssp. cantoniensis Kitam. and anemochore population also increased when mulch and no-tillage cultivation was applied (Table 2).
Rice yields had gradually decreased under this cultivation system as time pass-ed, whereas rice yields recovered by the application of glyphosate before sowing of rice and topdressing of fertilizer (Table 4).
On the other hand, to evaluate the suppression of summer paddy weeds by A. sinicus living mulch, mulch was removed in May and July. Mulch removal led to a significant increase of the density of summer annual weeds, especially Cyperus and Lindernia (Table 3).
These results, suggest that if the A. sinicus community grows thickly and becomes stabilized every year, A. sinicus living mulch is effective to suppress weeds in the case of rice cultivation without tillage as a form of low input and sustainable agriculture.View full abstractDownload PDF (1060K) -
Yuichiro Nakayama, Shinya Umemoto, Tokuichi Kusanagi1997 Volume 42 Issue 2 Pages 97-106
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSLife history traits of two types of Plantago asiatica L. s. l., the common and minima type, were compared by using experimental populations raised from the seeds collected from eight natural populations in Kyoto City (Table 1).
Remarkable genetic variation was observed in the life history traits between the two types. The minima type produced a smaller plant biomass, headed earlier, and allocated a larger amount of dry matter to reproductive organs earlier in the life cycle (Fig. 1 and Table 2). Although both types produced an equivalent number of seeds in the first year, the common type produced a larger number of seeds than the minima type in the second year (Table 2). High seed germination rates of the common type were obtained at 20, 25 and 30°C under light conditions, while the minima type showed a high germination rate only at 25°C under light conditions (Fig. 3).
Based on the results of ANOVA for the life history traits, it was considered that some environmental factors of habitats were closely related to the genetic variation of the two types (Table 1 and Fig. 3).
Phenological observations were made on eight natural populations of the two types to analyze life history strategies. The habitat of the common type, levee or path between fields, was characterized by a relatively high competition due to the high coverage of vascular plants and low mortality of adult P. asiatica plants. On the other hand, the habitat of the minima type consisting of grounds of shrine, was characterized by stress and unpredictable mortality due to disturbances, such as weeding, dry weather and sweeping in summer and repair work of the shrine (Fig. 4).
The life history strategies of the two types of P. asiatica seem to have evolved as adaptations to such unique environment and management of their habitats.View full abstractDownload PDF (1172K) -
Toshiyuki Ohtsuka, Masayuki Nemoto1997 Volume 42 Issue 2 Pages 107-114
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSStructure and dynamics of weedy riparian communities around agricultural areas and the effect of soil eutrophication were studied along the Hozaki river, Ibaraki Prefecture, central Japan. Communities with a high species diversity, consisting of a mixture of weedy species, e. g., Digitaria ciliaris and Persicaria longiseta, with ruderal species, e. g., Impatiens textori, were established in the upper stream area near a Cryptomeria japonica plantation, and nitrogen and carbon contents of the soil were significantly low. On the contrary, in the midstream area around paddy fields, nitrogen and carbon contents of the soil were five times higher than in the upper stream area, and communities with a low species diversity, consisting mainly of Persicaria thunbergii and Humulus japonicus, were established. In the holm of the lower stream, where the embankment was covered by concrete, Phalaris arundinacea dominated alone due to severe disturbances associated with the construction work.
Near the study sites of the midstream area, a pure community of Chenopodium album was established near a pile of pig dung. The nitrogen and carbon contents of the soil at the site were nearly twice as high as those of the site in the midstream area. Soil eutrophication in the midstream area due to organic matter from pig dung or chemical fertilizer from paddy fields, resulted in the predominance of nitrophilous weeds with a low species diversity. It is concluded that human impact affected the riparian vegetation not only around urban areas due to the presence of factories or home effluents, but also around agricultural areas through modern and intensive farming including rice cultivation or livestock breeding.View full abstractDownload PDF (915K) -
Seiko Imaizumi, Takane Fujimori1997 Volume 42 Issue 2 Pages 115-124
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSGrowth of a Rifampin-resistant strain (Rif-482) of Xanthomonas campestris pv. poae (JT-P482) in annual bluegrass monitored over several weeks indicates its potential as a tool for the study of interaction between X. campestris pv. poae (JT-P482, wild type) and annual bluegrass. After inoculation with 109cfu/ml of bacterial suspension, populations of both Rif-482 and JT-P482 in plant sections increased during the period from 3 days (1.0×108cfu/g FW) to 3 weeks after inoculation, when they reached a maximum (1.5×1010cfu/g FW). Subsequently, Rif-482 decreased to 5.4×108cfu/g FW 9 weeks after treatment (WAT). Efficacy (=% control) increased up to 4 WAT (86% control and 88% control of plants inoculated with Rif-482 and JT-P482, respectively) with plants showing the blighted and dried symptoms characteristic of heavy wilting. These results showed that the multiplication rate and efficacy of Rif-482 in plants matched those of JT-P482. The time lag between the peak of bacterial population (>1010cfu/g FW) and the peak of disease development (>80% control) was between one and two weeks. Tests of various initial inoculum concentrations of both isolates from 103 to 1010cfu/ml showed that the two followed a similar pattern of cell population increase and efficacy 3 WAT. The multiplication pattern of Rif-482 in the plant during the vegetative to early reproductive phases of plant growth was traced in different plant parts over time. Our findings show that Rif-482 bacteria inoculated to a leaf translocate systemically from the inoculation site through the stem to the root, then to all plant-parts. They also show a correlation between the development of disease and a decrease in the water content of plants, which appears to be the mechanism by which X. campestris pv. poae injures annual bluegrass.View full abstractDownload PDF (1726K) -
1997 Volume 42 Issue 2 Pages 124
Published: 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (45K) -
Seiko Imaizumi, Takane Fujimori1997 Volume 42 Issue 2 Pages 125-134
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDifferences in the effectiveness of Xanthomonas campestris pv. poae (JT-P482) on morphologically differing annual and perennial types of annual bluegrass were investigated. For experimental purposes, an annual type (taken from Utsunomiya) and a perennial type (taken from Tsumagoi) were selected based on morphological characteristics and seed dormancy periods. Bacterial multiplication rates and patterns of proliferation of JT-P482 in plants kept under different temperature conditions were quite similar in the two ecotypes; no differences in bacterial population densities were demonstrated in either of them. However, these ecotypes responded differently to JT-P482 treatment in terms of efficacy. Monitoring of the growth rates and number of stems of untreated plants showed that perennial type plants exhibited significant increases in growth, particularly in secondary tiller production, when compared to the annual type. These findings suggest that the competition between bacteria growth and plant growth causes the difference in response to treatment between the two ecotypes of annual bluegrass.View full abstractDownload PDF (3488K) -
Guangxi Wang, Tokuichi Kusanagi, Kazuyuki Itoh1997 Volume 42 Issue 2 Pages 135-143
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSEffects of time of sowing, shading and compound fertilizer application on the growth and seed production of Monochoria korsakowii and M. vaginalis were investigated in Kyoto, Japan. The results are summarized as follows.
When sown until May, M. korsakowii displayed a larger number of leaves on the main stem than M. vaginalis, while when sown from June, the results were opposite (Table 1). This phenomenon was attributed to the quicker growth of M. korsakowii under low temperature conditions in spring than that of M. vaginalis.
In the case of M. vaginalis, the amount of seeds which was larger in the weeds sown in May and June than in those sown in other months, tended to depend on the top dry weight. In the case of M. korsakowii, though the weeds sown in May and June also showed an amount of seeds as large as that of M. vaginalis, the top dry weight of the weeds sown in March and April was larger than in other months (Fig. 1 and Table 2).
In both species, partition of dry matter production to reproductive organs started at the late growth stage in the April sowing, while at the early stage in the August sowing (Fig. 2).
Both species exhibited maximum plant height under shading of 25% relative intensity, while seed production per plant increased when the dose of compound fertilizer applied increased. The results obtained suggested that the weed became adapted to shading and soil fertilizer. In a natural population where rice was present, both species grew better under shading by the canopy of rice and produced a larger number of seeds in soil amended with compound fertilizer.
Without shading, the amount of seeds increased considerably with the increase of the fertilizer level. Under the shading conditions, the amount of seeds of both species was largest when 25% shading was applied 90 days after sowing. On the other hand, the amount of seeds decreased with the increase of the shading level and when the onset of shading was advanced (Tables 3 and 4).View full abstractDownload PDF (2240K) -
Nobumasa Ichizen, Minori Aoki, Hitoshi Kuramochi, Makoto Konnai1997 Volume 42 Issue 2 Pages 144-146
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (366K) -
Nobumasa Ichizen, Han Zhu, Zhansheng Wang, Hidenori Takahashi, Satoshi ...1997 Volume 42 Issue 2 Pages 147-150
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (252K) -
Ie-sung Shim, Reiichi Miura, Etsuko Ishikawa, Masaaki Tachibana, Akira ...1997 Volume 42 Issue 2 Pages 151-160
Published: August 30, 1997
Released on J-STAGE: December 17, 2009
JOURNAL FREE ACCESSDownload PDF (1300K)
- |<
- <
- 1
- >
- >|