Soil 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 different plating time and seeding rate on their growths and reduction of wind speeds. Main results were followings.
Dry matter accumulations of cover crop 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.) and hairy vetch (Vicia villosa Roth). Planting times of cover crop and seeding rates also showed significant differences on their dry matter accumulations, especially, October planting times showed high dry matter accumulation although November 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 cover crop dry matter showed significant reduction of wind speed. Adopting cover crops in field crop 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 are significant.

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Paddy field rice can conserve N in the soil under flooded conditions. However, residual soil N represents a potential environment concern when fields are no longer flooded. Winter annual grass cover crops may provide an alternative means to conserve residual soil N following rice harvest. A two years field experiment was conducted at the Ibaraki University of Experimental Farm, to compare dry matter and N uptake by rye (Secale cereale L.), oat (Avena sativa L.), triticale (Triticum secale L) , wheat (Triticum aestivum L.) and fallow (no cover) in relation to soil residual N level.
Dry matter and N accumulation by the following April were in the descending order of rye>triticale>wheat=oat>fallow, while residual soil N levels followed the reverse order. Residual soil N level exerted the greatest influence on cover crop DM accumulation, with differences in N levels becoming more pronounced by the April sampling date. On 17 April, DM differences between the low and high residual soil N levels were 3.45 vs 6.82Mgha⁻¹ for rye (98% increase), 1.15 vs 1.45Mgha⁻¹ for oat (26% increase), 1.49 vs 1.99Mgha⁻¹ for wheat (34% increase), and 1.70 vs 2.98Mgha⁻¹ for triticale (75% increase), respectively.
Cover crop N accumulation followed patterns similar to those for DM, but was mainly influenced by main effect factors. Residual soil N level again exerted the greatest influence on N accumulation. Between species, N accumulation for rye was greater than oat and wheat across all planting dates. By 8 March, the greatest N accumulation occurred with rye (14.0kgNha⁻¹), with other species accumulating 5.4 to 7.5kgNha⁻¹. Cover crop N accumulation increased appreciably from 10 March to 17 April.
These results demonstrated that grass cover crops have a great potential for controlling soil residual N. However, additional research will be needed to determine the contribution of cover crop N to subsequent rice growth.

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We have investigated the use of air-assisted strip seeding for direct seeding in flooded paddy fields. A seeder was developed using a commercially available granule applicator remodelled for tractor installation. The seeder swath was widened, and the blow head was improved. The diameter of the blow head was reduced and the blow head was lengthened to improve seeding results.
Analysis using a high-speed camera of the effect of the air assistance used by the developed blow head showed that the speed of rice seed falling was from 4 to 7m/s and that the direction of falling was 7.1° from vertical. A sowing test using imitation paddled soil demonstrated that the developed blow head reduced the width of the sown strips by about 40% compared with a conventional head and that seeds were buried deeper. These results were confirmed by sowing rice seeds into an agar bed, which simulated a paddled paddy. The sown strips were from 50 to 80mm wide, and the seeds were buried less than 5mm deep.
These results show that an air-assisted seeder with an improved blow head can effectively seed flooded paddy fields.

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We investigated the effects of ammonium nitrate (NH₄NO₃, AMN) application with gibberellic acid (GA) at 13 days after full bloom on the skin color, size and other fruit qualities of tetraploid ‘Fujiminori’ and ‘Kyoho’ grape berries which were treated with 200ppm streptomycin at about three weeks before full bloom to eliminate seeds. Skin color development of ‘Fujiminori’ berries treated by 25ppm GA with 12.5 or 25mM AMN, was accelerated compared to berries treated with 25ppm GA alone. However, the application of AMN had no effect on the size and internal quality of berries in both cultivars.

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An analysis of the effects of safety equipment for riding-type tractors was conducted. Roll-over protective structure (ROPS) and seatbelts could be the most important safety equipment because overturn has occupied about 70% of all accidents on riding-type tractors. The diffusion and results of accidents of those were investigated through questionnaire survey, in which, 2618 farmers in 26 Japanese prefectures were sampled, 1428 of which participated in the survey.
It was found that 69% of tractors were equipped with ROPS and 50% of tractors had a seatbelt, although 55% of owners of these tractors did not use the seatbelts at all. In all, 289 accidents including 57 deaths were reported. 72% of all accidents and 68% of all deaths were due to overturning. In accidents due to overturning, the degree of injury with and without ROPS varied considerably : 25% of accidents without ROPS resulted in death but this rate decreased to 3% with ROPS. For accidents other than overturning, 42% of accidents and 61% of deaths were caused by being caught in or crushed by farming implements.
The effects of ROPS on overturning were quantified, and the use of seatbelts and safety equipment for farming implements were shown to reduce the number and severity of accidents.

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The effectiveness of low volume pesticide application using a mist blower against mulberry scale in tea cultivation was investigated. The pesticide adhesion to the branches and the effectiveness in controlling mulberry scale was tested using 2 types of blow heads of the mist blower and 2 application rate levels : 400 and 600L/10a. One of the blow heads was a downwash type, which directs the mist flow downward from above the canopy, and the other was a crosswind type, which directs the mist flow horizontally from both sides of the tree. The application rate of power sprayers used in conventional pest control methods exceeds 1000L/10a. The use of the downwash type blow head resulted in greater adhesion on the upper branches inside the canopy than on the lower branches. Further, the difference in the application rate didn't affect the degree of chemical adhesion. Both application rates were found to be effective against mulberry scale. On the other hand, when the crosswind type blow head was used, chemical adhesion at the center of the canopy was found to be insufficient under both application rate conditions. Further, less chemical adhesion was achieved when 400L/10a was applied as compared to when 600L/10a was applied. The efficacy against mulberry scale was confirmed only with the application rate of 600L/10a. On the basis of these results, we concluded that low volume pesticide application using the mist blower and the downwash type blow head was effective against mulberry scale.

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