Japanese Journal of Farm Work Research

» Vol. 45 (2010) | Vol. 44 (2009)

 

Vol. 45 (2010), No. 4

Release Date: June 20, 2011

  • Original Papers
    • Buzz-pollination Method by Wind for Tomatoes Using a Blower
    Hidetaka NAKAYAMA
    Abstract: Treating flowers with phytohormones has been considered necessary for stable fruit setting in plastic house culture of tomatoes. Compared with buzz-pollination, which vibrates flower clusters mechanically, spraying phytohormones requires less labor but it produces a higher proportion of puffy fruits.
    Recently, a new buzz-pollination method, which pollinates flowers easily by vibration of flower clusters by wind using a blower, was developed. To examine the effectiveness of this new method, its labor intensity, rate of fruit setting and proportion of puffy fruits were compared with the conventional buzz-pollination method and phytohormone treatment.
    The working time of pollination per plant with the new buzz-pollination, conventional buzz-pollination and phytohormone treatments was 2.8, 7.5 and 6.7 seconds, respectively. Buzz-pollination must be administered two or three times per week whereas one phytohormone treatment per week is enough. Estimated total pollination time of the new buzz-pollination method ranged from 8.2 to 9.6 hours per 1a, almost the same as the phytohormone treatment. This indicates that there is little difference in the labor intensity between the new buzz-pollination and the phytohormone treatment. Moreover, the rate of fruit setting in the new buzz-pollination was equal to the phytohormone treatment and no puffy fruit was observed with the new buzz-pollination.
    These results indicate that the new buzz-pollination is a useful method for stable fruit setting in plastic house culture of tomatoes.
    Analysis of Suitable Handling Position for High-wire Tomato Training System by Surface Electromyography
    Hideto KUROSAKI, Hiromi OHMORI, Masuyuki TAKAICHI and Hidekazu SASAKI
    Abstract: High-wire tomato training system requires plants to be periodically lowered. This is hard work because of the heavy plant weight and the awkward handling position. To determine the best handling position for workers, we analyzed muscle loads by using surface electromyograms. Over a season, the average load created by a suspended plant in a greenhouse was 45 N. We analyzed loads in simulated work from integrated surface electromyogram (iEMG) data. Among 10 muscle parts, the trapezius top and front deltoid showed the clearest responses to the load over the vertical distance to the training wire. The relationships between iEMG values and the load at these muscle parts were nearly linear. The iEMG responses were almost the same in one-arm work and two-arm work. For calculations, handling distances were converted in to the worker's height (height ratio). iEMG values were smallest at a height ratio of 0.45-0.55 at the top of the trapezius and of 0.60-0.65 at the front deltoid. Under actual greenhouse conditions, the optimum height of the wire above the work platform was estimated to lie in a height ratio range of 0.60-0.80, which allows good arm movement. The muscle loads of the front deltoid seemed to increase as the horizontal distance to the training wire increases. Too near, however, and the worker collides with the leaves. Therefore, a suitable horizontal distance was considered to be a height ratio of 0.25-0.30.
  • Research Paper
    • Effects of Mulching with Polyethylene Nonwoven Fabric on Growth and Fruit Quality of Dwarf Apple Trees
    Hiroyuki FUJISAWA and Yuki MORIYA
    Abstract: This study was conducted to investigate the influence of mulching cultivation using moisturepermeable polyethylene nonwoven fabric on soil moisture, tree growth, and fruit quality in scions of 12-year-old apple ('New Jonagold') trees grafted onto JM1, JM7, and M.9vf rootstocks.
    1) Although mulching resulted in a decrease in soil moisture, the soil remained rather humid (pF, approximately 2.0).
    2) Shoot elongation and fruit weight in trees grown under mulching cultivation appeared to be lower than those in the control condition, irrespective of the rootstock. This might be attributed to the decrease in soil moisture.
    3) Peel color at the calyx end of fruits appeared to improve with mulching, irrespective of the rootstock. Peel color at the equatorial region of fruits from scions grafted on JM7 and M.9vf was not affected by mulching, whereas it was reduced by mulching in the case of scions grafted on JM1.
    4) Mulching did not affect the Brix or acidity values of the fruits, regardless of the rootstock.

Vol. 45 (2010), No. 3

Release Date: March 10, 2011

  • Original Paper
    • A Study on the Use of Plant Residue Produced from Hydroponic Cultivation of Tomato in the Management Unit of Farmers
    Minoru TAKEMOTO, Yoko MIYAMA, Yoshihiro MUROI and Shunrokuro FUJIWARA
    Abstract: The use of plant residue produced from a hydroponic cultivation of tomato was examined in the management unit of farmers in Kanagawa Prefecture.
    It was shown that the suitable method for use of tomato plant residue produced in winter (late raising culture), was to cut with a cutter and then apply onto a rice field in the management unit of farmers.
    The other method was impossible to apply the tomato plant residue onto the rice field in summer, because rice was growing during this season.
    Therefore, it was shown that the suitable method for use of tomato plant residue produced in summer (semi-forcing culture), was to cut with a cutter and to be composted and dried in a flexible container bag, and after that, applied onto a rice field in the management unit of farmers.

Vol. 45 (2010), No. 2

Release Date: December 15, 2010

  • Original Paper
    • Estimating Spatial Distribution of Herb Species and Herbage Mass in Cover Crop Field Using Hyperspectral Imaging
    Yumiko SUZUKI, Hiroshi OKAMOTO, Toshiyuki HIRATA, Takashi KATAOKA and Youichi SHIBATA
    Abstract: Cover crops have many benefits such as reducing chemical materials, improving soil condition, preventing soil erosion and conservation of soil water. The long-term objective of this study is to assess and estimate cover crop effectiveness such as green manure, weed depression and soil conservation. In this paper, spatial distribution of herb species and herbage mass was estimated.
    A ground based hyperspectral imaging, which is useful for acquiring field information, was employed to monitor the cover crop field (bristle oat and hairy vetch). In order to generate the maps of herbage mass, first, plant portions were extracted from hyperspectral images by NDVI (normalized difference vegetation index) threshold. Next, they were classified into plant species using linear discriminant models. Finally, the herbage mass of each plant species was estimated individually using partial least squares regression model, and mapped with gradient colors depending on the estimated value.
    The results show that the success rate of plant area extraction was 100% and the success rate of the plant species classification was 78.7%. With regards to the result of the herbage mass estimation, the model that used both plant pixel spectra and plant cover rate as explanatory variables had the highest and most stable accuracy than the other models. The maps of plant species and herbage mass reflected the actual spatial distribution on the field. It was demonstrated that the hyperspectral imaging system developed in this study is a useful technique for monitoring the cover crop.
  • Research Paper
    • Study on Developing Helianthus Sowing Techniques in Upland Fields Converted from Rice paddy and Techniques for Increasing Yield in San-in Region
    Kimiyasu TAKAHASHI, Jun KUBOTA, Masahiro KAMEI, Rintaro OKUNO, Hiroshi FUJIMOTO and Tadashi YASUTAKE
    Abstract: Helianthus cultivated in upland fields converted from rice paddy often suffers from excess moisture injury and is difficult to sow appropriately using sowing machines now possessed by farmers. We conducted sowing tests in the fields of farmers using a simplified ridging method to cope with excess moisture injury and a replaceable sowing roll for helianthus. Furthermore, we studied inter-tillage and topdressing techniques in order to increase the helianthus yield.
    Helianthus seeds were sown at intervals of 80cm between ridges and 25cm between plants using the helianthus sowing roll in farm fields. The inter-tillage method with the ridger width reduced to about 20cm so as not to damage helianthus roots achieved a yield exceeding that where there was no weeding or where weeding was performed manually, and it was confirmed that a sufficient increase in yield could be expected if fertilization with nitrogen content of 2.1kg/10a and topdressing with 10kg/10a of nitrogen content are applied.
    Furthermore, the plant separation was compared between those fields where the sowing rolls for helianthus supplied to the local farmers' union were used and that in fields where no such rolls were used. A significant difference was found : 59.6% of the plants were appropriately spaced when sowing rolls were used, but only 37.1% of the plants were appropriately spaced when the rolls were not used. Fifteen sowing rolls for helianthus were distributed to local farmers in 2009, the year after the tests.

Vol. 45 (2010), No. 1

Release Date: September 20, 2010

  • Original Papers
    • Studies on the Work Load of the Aged Worker in Citrus Tree Fields
    Hirofumi KAWANISHI, Yoshihiro NISHIKAWA and Gab-soo DO
    Abstract: The work load of aged worker (a male, 78years) worked in the citrus tree fields was investigated as a case study. The results obtained were as follows.
    1) The average RMR (Relative metabolic rate) of the aged during chemical spraying work was 5.8 in the terraced fields, 4.0 in the steep slope fields, 3.6 in the slope fields and 3.3 in the horizontal fields. However, the maximum RMR was 6.9 in the terraced fields, 5.8 in the steep slope fields, 4.4 in the slope fields and 4.1 in the horizontal fields. The heart rate index and (%HRR/100, where %HRR is a % of the maximum heart rate reserve) were 67.1 and 0.61 in the terraced fields, 59.3 and 0.532 in the step slope fields, 58.0 and 0.519 in the slope fields, and 56.0 and 0.505 in the horizontal fields, respectively.
    2) In chemical spraying work, the heart rate of the aged workers continued increasing from the start of operations to the end. Therefore the aged should avoid chemical spraying work in the terraced fields.
    3) The average RMR of the aged worker was between 3.2 and 3.6 in picking fruit. The heart rate index in picking fruit was between 35.8 and 47.8, the elevation in heart rate index B showed the same degree as with RMR results, but the other heart rate index a lesser degree than RMR results. (%HRR/100) results were between 0.265 and 0.319, and lower than the RMR results.
    4) The RMR data from piling and discharging conteners of loaded fruit on the platform tracks were between 2.4 and 2.6. But the elevated heart rate index was between the lesser degree and higher degree during piling and between the same degree and the lesser degree in discharging than the RMR results. The elevation of (%HRR/100) was the same in piling and a lesser degree in discharging than the RMR results.
    Present Situation of Tractor Implement Row-following Operation in Large-scale Upland Farming
    Baoming SHEN, Tadatoshi SATOW, Kunihisa IMAMURA, Kazunori HIRONAKA and Tadashi KISHIMOTO
    Abstract: This study was to examine farmer's working conditions and the accuracy of tractor implements in following rows in a field, and to consider the most appropriate control speed of such implements as preliminary research for the development of an automatic guidance system.
    1) In the case of seeding and transplanting, 10 to 16 percent of farmers' work time (driving a tractor) was used to check the position of attached implements. In cultivating and weeding, it was 16?27%.
    2) Concerning the accuracy of the row-following function of tractor implements, uniformity in row spacing is important. However, in actuality, the spacing of most fields varies between rows. Differences in row spacing ranged from 7.5cm to 11.5cm in the cases of seeding and transplanting. Moreover, for cultivating and weeding, the biggest observed difference was 8.2cm. Consequently, implement damage to crops was observed.
    3) When tractor working speed was adjusted to 2m/s for seeding and transplanting, the control speed of an actuator for the automatic guidance system was calculated to be 6.6cm/s. The maximum control speed of the actuator must be at least 10cm/s for cultivating and weeding.
    Cultivation of One Seed Sowing Method in Japanese Radish cv. Natsutukasa
    Nobuyuki FUKUOKA and Hisashi HASHIMOTO
    Abstract: Methods for optimizing Japanese radish cv. Natsutukasa cultivation using single seed sowing were assessed for individual plants by examining variations in seed size, seed sowing depth, type of teep seeder machine, and the effect of urea fertilizer application.
    The highest rates of germination were found in seeds, which had seed diameters exceeding approximately 2mm. Seed sowing depth also affected germination in radish plants and the occurrence of vacant hills increased with sowing depths below 3cm. Application of two grains of urea fertilizer at distances of 2cm from each seed point increased root thickening during the latter growth stage. We think that this combined method for single seed sowing cultivation is of practical use because the occurrence of vacant hills is similar to those of ordinary thinning cultivation and root thickening growth is intensified.
  • Research Papers
    • Effects of Soil Compaction by Tractor Traffic on reclaimed soil in Isahaya Bay
    Tomohiro MIYAZAKI, Takashi OKAYASU, Yasunao YAMADA and Eiji INOUE
    Abstract: At a reclaimed field of Isahaya Bay, a vehicle running test was conducted using tractors, and the penetration resistance (cone index) of soil before and after the running was compared. From this result, the effects of a vehicle running load on tread-pressure characteristics and the formation of a hard pan that were observed in the reclaimed soil were investigated.
    The running compressed the soil near the surface, which increased the penetration resistance of the trodden place. An increase in penetration resistance became remarkable according to the number of running, and its span of effect spread in a depth direction.
    The penetration resistance after drying increased compared with the day just after the running test. On the other hand, through measurement ten days after the seepage, a decrease in penetration resistance was observed at all the depth. This phenomenon was due to a change in the suction of soil caused by drying and seepage, which verified that a change in soil hardness was also caused by a change in the water content of soil.
    As for the distribution of the penetration resistance of soil, the distribution region of lower penetration resistance spread further as the water content of soil increased. In particular, when water content was 68.4%, and soft soil was observed at up to the deeper soil. From these facts, it was considered that the compression of soil due to a vehicle running load under the condition of high water content was not liable.
    Tractor Power Requirement of No-Tillage Seeder under Different Cover Crop Residue Management
    Yanzhong ZHAO, Tiejun ZHAO and Masakazu KOMATSUZAKI
    Abstract: No-tillage with cover crop has great potential to improve soil quality, however, it is still not clear what no-tillage seeding technique should be used under cover crop residue mulch in upland crop production. In this research, to identify the optimum no-tillage seeding management, no-tillage seeder performance and power requirement were measured in relation to different cover crop residue management.
    The tractor power required for the no-tillage seeder was higher with rye cover crop than hairy vetch and a mixture of rye and hairy vetch. Cover crop residue also showed a significant difference in the power required by the no-tillage seeder. Mowing the cover crop significantly reduced the power requirement compared with bush cutting. Termination of cover crop growth was another factor that significantly affected the power required. Late April growth termination of cover crop showed a lower power requirement than early May growth termination. As the amount of cover crop residue increased, the power requirement also increased, although the rye and hairy vetch mixture showed relatively lower power requirement. These results suggest that rye and hairy vetch mixture and mowing treatment are appropriate for using a no-tillage seeder under cover crop residue mulch.
    Study on Efficient Heating Methods for Harvester to Prevent Secondary Infection of Red Perilla Bacterial Wilt
    Yuji NAGASAKI, Takefumi MATSUZAKI, Hiroaki TANAKA and Yoichi NAKAMOTO
    Abstract: Secondary bacterial wilt spread through a trimmer blade of a harvester has become a major issue in red perilla when crops are rotated in rice fields. To prevent infection, the trimmer blade must be heated above 90°C. Therefore, we considered an efficient method of sterilization in which the trimmer blade is heated.
    A direct method for heating the trimmer blade is hindered by the blade action : the wires might be cut by the trimmer blade swing at high speed. The obstacles were overcome with a method of indirect heating achieved with a cover plate over the trimmer blade, which included a built-in micro-sheath heater that exceeds the 90-degree requirement.

Vol. 44 (2009), No. 4

Release Date: June 20, 2010

  • Original Papers
    • Influence of Cover Crop Seeding Date and Their Amounts on Mitigation of Wind Erosion
    Masakazu KOMATSUZAKI and Kotaro SUZUKI
    Abstract: 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.
    Nitrogen Uptake by Cover Crops and Inorganic Nitrogen Dynamics in Andisol Paddy Rice Field
    Masakazu KOMATSUZAKI
    Abstract: 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-1for 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.
    Development of Air-assisted Strip Seeding for Direct Seeding in Flooded Paddy Fields―Seeding Machine and Effect of Air Assistance―
    Tadashi CHOSA, Masami FURUHATA, Masaaki OMINE and Osamu MATSUMURA
    Abstract: 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.
  • Research Papers
    • Effects of Ammonium Nitrate Application on Skin Color Development of Streptomycin-Treated Seedless 'Fujiminori' and 'Kyoho' Grape Cultivars
    Kazunori ISHIKAWA and Tadashi BABA
    Abstract: 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.
    Analysis of the Effects of Safety Equipments for Riding-Type Tractors through Farmer Survey
    Muneki TOMITA, Tomomichi MIZUKAMI, Masamitsu TAKAHASHI and Shigeyoshi TSUKAMOTO
    Abstract: 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.
    Control Method and Effect of Low Volume Pesticide Application to Mulberry Scale, Pseudaulacaspis pentagona (Targioni), Using Mist Blower in Tea Field
    Daisuke MIYAMA, Osamu SUMIKAWA, Takuya ARAKI, Yasushi SATO, Chikara ISHIJIMA and Katsuji TERADA
    Abstract: 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.

Vol. 44 (2009), No. 3

Release Date: March 20, 2010

  • Original Papers
    • Effect of Legume Incorporation or Living Mulch on Rice Growth, Yield and Soil Inorganic Nitrogen in Southwest Japan
    Naomi ASAGI and Hideto UENO
    Abstract: The effects of cover crop on rice growth, yield, and nitrogen in soil were investigated and compared with those of chemical fertilizer (CF) and no fertilizer (NF) application in the Shikoku region of Japan. White clover (WC) was incorporated into paddy soil (WCIN) or used as living mulch without tillage (WCLM). A field experiment was conducted in 2004 and 2006. The NH4-N level in the soil of WCIN was higher than that in NF at 1 day after transplanting (DAT). Rice height, number of tillers and leaf chlorophyll content (SPAD value) at 50, 97, and 114 DAT, the number of spikelets and yield per unit area at 114 DAT in WCIN were higher than those in NF. These findings indicate the positive effects of WC incorporation on soil nitrogen, rice yield, and nitrogen uptake. In WCLM, the NH4-N level in soil was lower than that in NF at 1 DAT. The yield per unit area in WCLM was lower than that in CF and WCIN. This may be due to the lower numbers of panicles and spikelets per unit area in WCLM. These suggest that effects of WC living mulch on nitrogen supply to rice, increase of the numbers of panicles and spikelets were lower than those of WC incorporation. In order to increase rice yield in cultivation with a cover crop, it is necessary to increase yield of cover crop and improve methods of fertilization suitable for each application with cover crop (incorporation, living mulch).
    Comprehensive Evaluation of Productivity and Environmental Loads in a Paddy Field Under Different Fertilized Conditions
    Rumiko KUROKAWA, Hisayoshi HAYASHI and Naoki SAKAI
    Abstract: The effect of fertilized conditions on environmental loads of methane emissions and water quality in a paddy field and the yield of rice were comprehensively evaluated. The experimental plots were no-fertilizer plot (0), NPK plot (N, P2O5, K2O 7.5g/m2 each), NPKM plot (N,P2O5, K2O 7.5g/m2 each, rice straw manure 1000g/m2) and 2NPK plot (N 15.0g/m2, P2O5, K2O 7.5g/m2 each). Total nitrogen concentration (TN) in the flood water increased at basal application and top dressings but total phosphorus concentration (TP) increased at basal application only. The total methane emissions during the rice growing period and the weight of winnowed rough rice were ordered as follows : 0<NPK<NPKM<2NPK. There was a positive correlation indicating methane emissions increase with higher rice yield. Approximately 80% of the total methane emissions occurred after heading. Total methane emission, TN and TP were calculated per unit yield of winnowed rough rice, expressed as the proportion of the NPK plot, and recorded in a radar chart. This chart was very useful for comprehensively assessing the productivity and environmental loads. Manure input increased methane emissions but decreased TP. Double input of nitrogen increased methane emissions but didn't affect the environmental loads in the water. Therefore, the influences on environmental loads per unit yield widely differed with the kind and amount of fertilizer used.
    Effects of Girdling, Strapping, and CPPU Treatments on Fruit Quality in 'Fuyu' and 'Jiro' Persimmon
    Yoshitaka KAWAI, Kazunori ISHIKAWA and Hiroyuki FUJISAWA
    Abstract: This study was undertaken to investigate the effects of girdling and strapping of lateral branches, combined with application of CPPU (N-(2-chloro-4-pyridyl)-N′-phenylurea) to the fruitlets, on fruit quality of two cultivars of Japanese persimmon (Diospyros kaki L., ‘Fuyu’ and ‘Jiro’). Girdling in May and July and strapping in May, June and July significantly increased fruit size and weight of ‘Fuyu’. Strapping in May, June and July increased fruit sugar content of ‘Fuyu’ and enhanced fruit quality more than girdling in ‘Fuyu’. Girdling in June significantly increased fruit size and weight of ‘Jiro’. Because girdling and strapping in May or June showed the best results in both cultivars, it is suggested that these treatments are suitable for persimmon during the first half of stage I of fruit development. The combination of girdling and CPPU significantly increased fruit size in ‘Fuyu’, and CPPU decreased fruit size in ‘Jiro’. CPPU decreased fruit color and sugar content in both cultivars.
    Analysis of the Spatial Heterogeneity of Wheat Yield Based on Complex Adaptive Systems' Approach
    Tetsuro KATAOKA, Hirofumi KUBOTA and Satoshi YONEKAWA
    Abstract: Twelve experimental sections of 4 rows×3m were established to examine the heterogeneity of a 72-a wheat field. Using 20 sample yield values from each experimental section, the heterogeneity of the field size was examined using the coefficient of variation through experimental section size and zoning size, which was a combination of several experimental sections. In addition, experimental section size and optimal number of samples in zoning were examined by randomly reducing the number of samples and by weighing the sample values. The results indicated that the space distribution of soil nitrate content and soil moisture content as well as the direction of movement of tractors affected the yield in this test agricultural field, indicating that these can be used as environmental factors in the concept of complex adaptive systems. This test agricultural field, sampling efficiency was improved by zoning the field into 4 sections, each of which had approximately the same environmental factors.
    Apparent Nitrogen Mineralization Rates of Several Green Manures Incorporated in Soil and the Application Effects on Growth of Komatsuna Plants
    Mohammad Zarif SHARIFI, Shoji MATSUMURA, Tadashi HIRASAWA and Masakazu KOMATSUZAKI
    Abstract: Apparent nitrogen mineralization rates and the availability of released nitrogen to komatsuna plants succeeding green manures (GMs) incorporated to soil were investigated using a pot experiment to develop a reasonable crop rotation system that decreases environmental loads by ensuring nutrient cycling. Four GM residues―hairy vetch (HV), sunflower (SF), crotalaria (CR), and upland rice (UR)―were mixed with soil, respectively, to produce 200kg N ha-1. Furthermore, a fertilizer (F) plot with the same N amount of chemical fertilizer applied and a control (C) plot with no amendment were set. Komatsuna plants were grown for 75 days under the treatments in a plastic green house. Plants were sampled five times to determine their dry weights and nitrogen contents. Dry weight yields of komatsuna were highest in F plot, with those of HV and SF plots following, although that of UR plot was less than that of C plot. The N content of komatsuna showed similar results. Absorbed N, as derived from the amendments, was greatest in F plot, followed by HV and SF plots, although the UR plot had less than control. Regarding apparent nitrogen mineralization rates which were calculated by subtraction method, significant differences were found between HV and CR, and HV and UR plots, and between SF and CR, and SF and UR plots, but not between HV and SF. Inorganic nitrogen in soil was higher in HV and SF plots than CR and UR plots. The residues of HV and SF demonstrated preferred characteristics as GMs for a nitrogen supplier to succeeding crops.
  • Research Paper
    • A Case Study of Organic Rice Production System and Soil Carbon Storage in West Java, Indonesia
    Masakazu KOMATSUZAKI and M. Faiz SYUAIB
    Abstract: Organic farming provides a lot of benefits in Indonesia, because it can improve soil quality, food quality and soil carbon sequestration. This research was designed to evaluate the ability of soil carbon storage by making comparisons between conventional and organic farming systems for rice production in West Java, Indonesia. The results from soil analysis indicated that organic farming had significantly higher soil carbon storage capacity than conventional farming. Organic farming can also cut some costs for farming, but it requires about twice as much labor. The sharecropping system of rice farming in Indonesia is highly exploitative of workers ; therefore, research should be conducted to develop a fairer organic farming system that can enhance both local and global sustainability.

Vol. 44 (2009), No. 2

Release Date: December 20, 2009

  • Original Papers
    • Effectiveness of Utilizing an Improved Simple Net Fence to Prevent Agricultural Damage by Wild Monkeys
    Hiroyuki FUJITA, Toshio FUKUI and Yoshinori KUNIMOTO
    Abstract: To mitigate problems occurring from the use of simple net fences, we examined the effectiveness of an improved net fence in preventing monkey invasion of agricultural fields surrounded by such fences and eliminating the resultant agricultural damage. A monitoring camera, on-site research, and interviews verified the monkeys' appearance, behavior, and agricultural damage.
    The simple net fence's durability was improved by substituting the easily deteriorated nylon net material with polyethylene. Furthermore, covering the lower part of the fence to keep monkeys from viewing agricultural fields further enhanced the fence's performance in preventing monkey invasion and consequent damage.
    Although a double-mesh version, elaborated from a simple fence to ward off more experienced monkeys, had previously been developed, it was found to be less effectual. In contrast, a simple electrified net fence―the original version combined with electrical deterrents―completely stopped monkey invasions, and no agricultural damage occurred.
    Nonetheless, psychological barriers to monkeys, such as agricultural workers frightening them off, were also thought necessary to maintain the overall effectiveness of invasion-prevention fencing.
    A Field Drainage Improvement Technique for Increasing the Working Period in Sugarcane Fields
    Koichiro FUKAMI, Mitsuho SUGIMOTO, Yoshiaki SHINZATO and Tohru AKACHI
    Abstract: To increase the number of days for which an agricultural machine in sugarcane filed of Jahgaru soil, which is heavy clay soil found in Okinawa, we developed a simple field drainage improvement technique that included subsoil breaking and drainage pit creation. Next, we determined the effects of this technique by setting the limit working conditions for the machines ; these conditions were derived from field experiments. The limit working condition for sugarcane cultivation, excluding harvesting conditions, was soil water content of ? 30%. When the total rain value was ?50mm, the number of days for which a machine could function was 4 days more than that in a conventional setting. On the basis of these results, the area covered by the machine increased by approximately 4 and 5ha in the planter at summer planting and the hiller at spring and root planting respectively. The cost incurred for creating the drainage pit was approximately 37,000Yen. However, if the renewal timing considered as once every 4 years, then the cost averages to approximately 9,000Yen.
  • Research Paper
    • Effects of Blower-Type Insect Trapping Treatment during the Growth Period of Second Tea Crop on Occurrences of Insect Pests, Yields and Qualities of Tea
    Daisuke MIYAMA, Katsuyuki YOSHIDA, Yasushi SATO, Osamu SUMIKAWA, Takuya ARAKI and Masahiro MIYAZAKI
    Abstract: An insect-trapping machine with a blowing apparatus, which uses mist air flow to blow off and trap insects on tea plants, has been developed as a physical pest control method used in tea cultivation. This technology has been shown to be effective for controlling pests and may enable pesticide-free tea cultivation. We examined the effect of treatment with this insect-trapping machine on tea pests, tea yield, and the quality of the second tea crop by using plots treated once a week, those treated twice a week, untreated plots, and chemically treated plots. During the growth period of the second tea crop, twice-weekly treatment with the insect-trapping machine was found to be effective for the reducing in the number of tea green leafhoppers. In contrast, once-weekly treatment had no effect on the number of leafhoppers. Moreover, both once-weekly and twice-weekly treatments had no effect on the incidence of yellow tea thrips. The yield was greater in the plot that was treated twice-weekly than in the plot that was treated once-weekly and was approximately equal to that in the chemically treated plot. The scores of sensory tests on tea manufactured from the plot that was treated twice-weekly were higher than those in the case of the plot treated once-weekly and approximately equal to those in the case of the chemically treated plot. On the basis of these results, we conclude that twice-weekly treatment with the insect-trapping machine is recommended for maintaining the yield and quality of tea obtained using pesticide-free cultivation.

Vol. 44 (2009), No. 1

Release Date: September 16, 2009

  • Original Papers
    • Agrochemical-Free, Direct-Sowing Culture of a Paddy with Non-woven Fabric Mulch―Timing of Puddling and Leveling and Basal Fertilizer Application―
    Shaikh Tanveer HOSSAIN, Hideki SUGIMOTO, Jun YAMASHITA and Joel M. ALCARAZ
    Abstract: In direct-sowing rice culture using cloth mulch, puddling and leveling (P & L) is usually done 2 days before the mulching (sowing). However, the mulching is very difficult, due to the muddy condition of the soil. Comparative studies were made to observe the effects of the timing of P & L, that is, P & L 10 days before mulching (P10) vs. P & L 2 days before the mulching (P2), on the operator's physical stress, the rice growth, and grain yield. Basal fertilizer was applied 2 days before the mulching in the P2 treatment (P2-B2), and topdressing was applied at 29 days before heading in all treatments. For the P10 treatment, timing of the basal fertilization was set at 14 (P10-B14) or 3 (P10-B3) days before the mulching.
    Results revealed that the timing of basal fertilization had no significant effect on the growth and grain yield between P10-B14 and P10-B3 treatments. The operator's physical stress was very low due to higher soil hardness in the P10-B14 treatment ; however the grain yield was 12% lower than that of the P2-B2 treatment due to lower percentage of ripened grain. Because of the lower inorganic nitrogen of the soil, the growth of leaf area was suppressed and dry matter production was lower in the P10-B14 treatment, which resulted in lower percentage of ripened grain. To increase the grain yield of the P10-B14 treatment, future research is needed to consider the application amount and timing of topdressing, and also to reduce the gap between P & L time and mulching.
    Determination of the Effects of Break Times and Caffeinated Coffee Based on Earlobe Pulse Rate Analysist
    Kiyo YAMADA, Jun YAMASHITA and Tiejun MIAO
    Abstract: This paper investigates the stress of a static worker using work load, pulse rate and chaos system analysis to determine the effect of rest during work for stress reduction, and the effect of caffeinated coffee on the body of a static worker. The method used in three experiments to create stress for the static worker was the Uchida-Kraepelin test. The first experiment showed that drinking a beverage was better than not during 5-minute breaks. The second experiment included a 20-minute break providing the subjects with beverages with and without caffeine. When the correct answers were checked along with pulse rate and chaos attractors, the effect of the break time was more positive for those who drank caffeinated coffee. The number of subjects was increased from 10 to 38 and we applied the double-blind test to investigate the detailed effect of caffeine. The subjects were required to work up to 150 minutes. The 150-minute test was divided into 10 rounds with 15 minutes in each round. Based on the results, the subjects who drank caffeinated coffee exhibited better performances on the test than those who drank non-caffeinated coffee. The pulse rate test showed that consuming caffeine resulted in the reduction of the pulse rate. Based on the findings, break time was very important for static work. Likewise, drinking caffeinated drinks can improve body performance.
    Workability of "No-box Seedlings" Using Seed Mats of Rice
    Hiroyuki SHIRATSUCHI, Hisashi KITAGAWA, Akio OGURA, Kazuyasu NAKANISHI and Mitsunori SUZUKI
    Abstract: Using a “seed-mat” consisting of hardened rice seeds glued onto a molded rice-hull mat covered with soil glued on, we raised rice seedlings without nursery boxes. The objective of this study is to elucidate the workability of “no-box seedlings” using seed mats. We raised conventional and no-box seedlings in a plastic greenhouse to compare the labor time, weight and tensile strength of seedling mats, characteristics of seedlings and transplanting accuracy between the two seedlings. The labor time required to prepare the no-box seedling was 20.7min/20seedling mats (almost equivalent to 10a), which was about one third that required to prepare the conventional seedlings. The weight of no-box seedling mats was 2.8kg and less than half of that of the conventional seedling boxes. The tensile strength of the no-box seedling mats was 169N/28cm and slightly less than that of the conventional seedling mats, which was strong enough to be rolled and handled without damage. The no-box seedlings were raised one to six days longer than the conventional seedlings. As a result, the no-box seedlings were as tall as the conventional seedlings. Leaf age and seedling weight of the nobox seedlings were similar to or slightly greater than those of the conventional seedlings. When mechanically transplanted, the rate of missing hills of the no-box seedlings was higher than that of the conventional seedlings, but less than 7%. The no-box seedlings save labor time to prepare for raising seedlings in spring and reduce labor intensity to handle the seedling mats.
  • Research Papers
    • Application Timing of Gibberellin with CPPU for Seedless Berries Induced by Streptomycin in 'Fujiminori' Grape
    Kazunori ISHIKAWA and Tadashi BABA
    Abstract: Effects of gibberellin (GA) with 1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU) application at different dates after full bloom were investigated for producing enlarged and high quality berries in streptomycin(SM)-treated ‘Fujiminori’ seedless grapes.
    1) Applying GA with CPPU 10 or 15 days after full bloom continuously increased berry size even after the beginning of veraison. Decline in L* value and peak of a* value of skin were delayed one week by either treatment.
    2) The rate of seedless berries increased by the SM treatment. Later application of GA with CPPU produced heavier berries. Rachis elongation was suppressed by applying GA with CPPU 10 or 15 days after full bloom. Later application of GA with CPPU caused lighter skin color and lower Brix.
    3) In conclusion, applying GA with CPPU 5 days after full bloom produced dark skin color of seedless berries and moderately compact clusters in SM treated ‘Fujiminori’ grapes.
    Effects of Concentration and Application Timing of Streptomycin on Berry and Cluster Characteristics of 'Fujiminori' Grape
    Kazunori ISHIKAWA, Tadashi BABA, Hiroyuki FUJISAWA and Tatsuya SEKI
    Abstract: Experiments were conducted to clarify the effects of lower concentrations of streptomycin (SM) application on seedlessness percentage and bunch quality of ‘Fujiminori’ grapes.
    1) Application of 100ppm or 200ppm SM before flowering produced approximately 100% seedless berries. 100ppmSM induced lager berries and rachis and lower acidity compared to 200ppm SM (conventional). No deleterious effects were detected in berries treated with 100ppmSM.
    2) Application of 100ppmSM with 25ppm gibberellin (GA) at the flowering stage in aim to reduce labor also produced enlarged berries, but lowered seedlessness percentage compared to the single SM application before flowering. Application of 200ppmSM with GA three days before full bloom produced berries that were nearly 100% seedless and of high quality in terms of color, sweetness and acidity.
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