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Volume 43 (2008)
- Issue 4 Pages 165-
- Issue 3 Pages 117-
- Issue 2 Pages 53-
- Issue 1 Pages 1-
Volume 43, Issue 4
Displaying 1-6 of 6 articles from this issue
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Original Papers
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Hiroyuki TSUJI, Yasuo OHSHITA, Kenji KIMIWADA, Shizuko ISHIKAWA2008 Volume 43 Issue 4 Pages 165-177
Published: December 25, 2008
Released on J-STAGE: June 25, 2009
JOURNAL FREE ACCESSThe effectiveness of the use of living mulch for shortening the weed-free maintenance period for soybean production was examined for the weed species black nightshade, barnyard grass, Persicaria lapathifolia (L.) S.F. Gray and common purslane. Living mulch greatly reduced both plant height and maximum shoot length of all weed species. The weed-free maintenance period was calculated from the rate of increase in plant height based on the assumption that relative illuminance on the ground reaches less than 10% on July 30 and August 5 and that plant height at that time point was less than 350mm. The results of calculation showed that using living mulch cropping system reduced the periods for weed-free maintenance by about 15 days for barnyard grass and by about 20 days for Persicaria lapathifolia (L.) S.F. Gray compared to the periods in conventional cropping system. The same calculation for black nightshade showed that the period for weed-free maintenance was reduced by about 35 days compared with that in conventional cropping. However, the results of field investigation of suppression of weed growth and production of fruit, which is the source of stain of soybean grain, showed that the actual reduction of the weed-free maintenance period for black nightshade is thought to be about 20 days. The growth of common purslane was almost completely suppressed by the use of living mulch. The results suggest that the weed-free maintenance period for soybean production using living mulch in Hokkaido is less than 30 days.View full abstractDownload PDF (1264K) -
Kei ISHIKAWA, Hideya KIMURA2008 Volume 43 Issue 4 Pages 179-186
Published: December 25, 2008
Released on J-STAGE: June 25, 2009
JOURNAL FREE ACCESSThe nitrogen dynamics in a sod culture of the satsuma mandarin orchard were determined by using 15N-labeled rat tail fescue (Vulpia myuros). 15N-labeled rat tail fescue plants were applied to the soil surface in an orchard and pot experiments. The satsuma mandarin trees began to absorb the nitrogen decomposed from the dead rat tail fescue 80 days after application. The absorbed nitrogen was translocated to current various organs of the satsuma mandarin trees and even to newly developed organs to the following spring. Similarly, newly reseeded rat tail fescue also absorbed the nitrogen. The satsuma mandarin trees and the reseeded rat tail fescue absorbed nearly the same amount of derived nitrogen from the dead rat tail fescue. The 15N content was high in newly developed organs, one-year-old leaves and fine roots of the satsuma mandarin trees but low in fruit. The rate of nitrogen occupied by supplied nitrogen was much greater in the reseeded rat tail fescue than the satsuma mandarin trees. Besides, the under-ground parts of reseeded rat tail fescue showed the greater level than the above-ground parts. The utilization efficiency of nitrogen decomposed from the dead rat tail fescue was 5.5% and 5.4% in satsuma mandarin trees and reseeded rat tail fescue, respectively. It was estimated that about 11% nitrogen was utilized from application in May to following next spring.View full abstractDownload PDF (856K) -
Masakazu KOMATSUZAKI, Kotaro SUZUKI2008 Volume 43 Issue 4 Pages 187-197
Published: December 25, 2008
Released on J-STAGE: June 25, 2009
JOURNAL FREE ACCESSSoil wind erosion is a serious issue in upland fields, because winter fallow treatments produce awful erosions in Kato area, Japan. This research evaluated the abilities of cover crops that planted at inter row spaces in Chinese cabbage (Brassica rapa var. glabra) production on their growths, crop yields, and reduction of wind speeds. Main results were followings.
There was little crop yields differences between uni-culture of Chinese cabbage and bi- culture of that with grass cover crops. Dry matter accumulations of cover crops were significantly different depending on their species and planting time. Cereal rye (Secale cereale L.) showed high dry matter accumulation compare with oat (Avena sativa L.). planting time of cover crops also showed significant difference, October and early November planting time showed high dry matter accumulation although late November and December planting time showed low dry mater accumulations due to delay of germination in the fields.
The significant difference was observed between cover crop biomass and the reduction of wind speed at the soil surface, 50g/m2 oat dry matter showed significant reduction of wind speed although rye needs over the 100g/m2 to reduce the wind speeds. Because of the difference of their growth type between standing type for oat and spreading type for rye.
Adopting cover crops in Chinese cabbage production may contribute to cope with both maintaining crop production and mitigation of wind erosion. In addition cover crops also recommend in the view points of sustainable agro ecosystem because their abilities that add organic matter to the soil is significant.View full abstractDownload PDF (1152K)
Research Papers
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Sakae HORIMOTO, Yoshiharu FUJII, Hajime ARAKI2008 Volume 43 Issue 4 Pages 199-205
Published: December 25, 2008
Released on J-STAGE: June 25, 2009
JOURNAL FREE ACCESSHairy vetch (HV) was sown (4kg/10a) in paddy December fast, 2001 and was incorporated or mulched before transplanting of rice, May 17th, 2002. The effect of the middle seedlings was estimated for overcoming delayed growth and low yield of rice in the paddy with incorporated or mulched hairy vetch, comparing with young seedlings. Nitrogen contents of leaves of middle seedling-planted rice in HV-incorporated (3.8%) and HV-mulched (3.6%) paddy were higher than that of young seedling-planted rice in conventional paddy (3.5%), tilled and no HV, 28 days after transplanting, June 20. Plant length of middle seedling-planted rice was higher than that of young seedling-planted rice in paddies with or without hairy vetch 56 days after transplanting (July 18). The tiller number of middle seedling-planted rice was increased to 9.7 in the HV-incorporated paddy, whereas, it reduced to 6.8 in the HV-mulched paddy, compared with tiller number (8.0) of young seedling-panted rice in the conventional paddy. Similar LAI in middle seedling-planted rice in incorporated and mulched paddy was shown to that in young seedling-planted rice in conventional paddy 78 days after transplanting, August 10. Grain yield of young seedling-planted rice in the paddy with HV was 62.6% to 67.3% of conventional paddy, however it increased to 81.4% to 85.6% by transplanting of middle seedling in the paddy with HV. From these observations, possibility to overcome the delayed growth and low yield by middle seedling-planting was shown in the HV-incorporated and HV-mulched paddy.View full abstractDownload PDF (624K) -
Relationship between Winter Cereal Cultivars as Living Mulch and Weed Control in Soybean CultivationShigenori MIURA, Hiroyuki KOBAYASHI2008 Volume 43 Issue 4 Pages 207-212
Published: December 25, 2008
Released on J-STAGE: June 25, 2009
JOURNAL FREE ACCESSWeed control and soybean yield were used as measures of the efficacy of eighteen winter cereal cultivars as living mulch. Each cereal cultivar grew well until the beginning of July, and then gradually died off. Shading of the soil surface differed by cultivar, but only cvs. Shinjyuboshi and Benkeimugi provided shade in excess of 90%, a level which has been reported to strongly suppress weed growth. The degree of shading correlated with cereal dry matter and the cereal multiplied dominance ratio (MDR). Weed dry matter at the beginning of August was negatively correlated with cereal plant height and MDR. These results indicate that MDR is an appropriate index for estimating weed control with cereals as living mulches. Soybean yields from field plots with living mulch were lower than from conventional cultivation plots, likely because of imperfect control of barnyardgrass and ladysthumb, which are comparatively shade tolerant.View full abstractDownload PDF (580K)
Comment
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Hajime ARAKI2008 Volume 43 Issue 4 Pages 213-214
Published: December 25, 2008
Released on J-STAGE: June 25, 2009
JOURNAL FREE ACCESSDownload PDF (196K)
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