The effects of the medium pruning of shoot on the growth habit of roots and root system was examined in flat level tea field. The dying-off of the rootlets by the pruning reached all root systems from the stock element to the in center of space between hedges . Therefore, the effects of the pruning appearred the rootlets most. The rootlets decreased by dying-off. Particullary, the central rootlet of space between hedges decreased. However, the proportion of the active white rootlet in the rootlets increased by the pruning. The fertilization after the pruning was examined with that the full-face fertilization including the stock element part was effective because there were the less decreases of original rootlet quantity in the hill base. The increase in the rootlets was observed in August during the growth of the aerial part. By the pruning of shoot it was observed that the growth of the root was accelerated.

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We investigated the effect of girdling and treatment with Gibberellin 3 (GA_3) and N- (2-chloro-4-pyridyl)-N'-phenyl urea (CPPU) on early-stage fruit drop rate and Indole-3-acetic acid (IAA) content in shaded or unshaded Japanese persimmon (Diospyros kaki Thunb. cv. 'Tonewase'). Fruit set was less than 10% 55 days after full bloom (DAF) in unshaded control (non-treated) trees. Fruit set at 50% shading was about 65% in GA_3 treated and girdled trees but about 10% in control trees 16 DAF. There were no significant differences in flesh IAA content on 20 DAF among treatments. The IAA content of sepal in shaded was lower than that in unshaded. The IAA content ratios (sepal/flesh) on 20 DAF in shaded and unshaded treatments were about 1.0 and 1.9 respectively.

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In the case of stationary type drying in rack drying systems, as the depth of paddy is relatively wide and ranges from 400 to 800 mm, drying speed is limited to prevent over-drying in the lower grain portion which is located on the air blowing side. In order to increase the drying speed while maintaining the quality of grains, the grain heating/drying system which raises the temperature of grains prior to ventilation was developed and evaluated. The results of evaluation tests are as follows: 1. The grains of entire depth were dried for one hour from the beginning of drying. The drying speed has increased 15% as compared with the conventional drying without heating. 2. The effect of heating becomes smaller as the moisture content of paddy is lower. Therefore, the energy efficiency of the system is higher when more heating processes in number with less ventilation period are applied at a higher moisture content, and no heating is applied at a lower moisture content. 3. When the grains are heated after mixing and then tempered, the moisture migration in a grain is expedited and the variation of moisture contents on dried grains becomes smaller. This effect is larger when the initial moisture content of paddy is higher. 4. The difference of moisture contents between the simulation of grain heating/drying, and the experiments was 0.22-0.53% on wet basis. Therefore, it has been confirmed that this simulation is useful to estimate the drying speed on the grain heating/drying system.

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As there is a close relationship between air flow rate and drying performance, it is necessary to study on this subject to improve the performance of rack drying systems. In such systems, as one blower is used to every container, the air flow rate of each container is influenced by not only the height of deposited grains but also the position of container. Under the circumstances, the ventilation characteristics of rack drying systems were analyzed through experiments and simulation method. The results are as follows: 1. When the amount of grains fed into containers is same, there is little variation of "ratio of air and grain" (air flow rate per ton of grain) regardless of distance from blower to container, and the air flow rate does not vary in the different positions of containers. 2. As the ratio of air and grain varies according to the height of deposited grains in a container, the height influences on drying speed. 3. When the amount of grains fed into containers is same, the variation of height of deposited grains in a container does not influence on drying speed.

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The high-speed grain dryer is equipped with a heating section between the tempering tank and dehydrating section of the dryer. The heating by the heating tubes, which are inserted in deposited grains, is accomplished by radiation/conduction/-convection. In this study, experiments on the radiation performance of far-infrared ray on the heating tubes were conducted and the following results were obtained. 1 . In case the heating tubes installed in the heating section of the high speed grain dryer were heated to 353 K (80℃), the radiation rate of far-infrared ray was approximately 0.6. 2 . The radiation energy that grains obtain exponentially varies according to the distance from the radiation surface to the grains and becomes smaller as this distance is larger. In case the temperature of the radiation surface and the distance to the grains are determined, less energy is required under the conditions of lower temperature and shorter distance. 3 . The middle radiation wavelength of far-infrared ray from the heating tubes of the high-speed grain dryer is in the absorption wavelength range of paddy. Thus, the paddy can absorb far-infrared ray efficiently.

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A newly developed accelerometer was evaluated for a simplified measurement of farm worker' s load. Since this accelerometer is compact and light, it can be easily put on the farmer's waist. We have found a significantly positive correlation between the workload measured with the accelerometer and the heart rates in two dynamic muscular works such as tea plucking and grass clearing operation. In contrast, we have not found it in two static muscular works such as berry thinning of grapes and harvesting of tomatoes for processing. Two-year studies on three farmers working with the accelerometer in daily farm works demonstrated the followings; 1) the simplified workload showed characteristic patterns according to the types of crops and the contents of works, 2) there was a high correlation between the decrease in body weight after works and the simplified workload, 3) the simplified workload exhibited useful indicators for physical activity patterns in different cultivations, and 4) the farmers who had worked with the accelerometer for 2 years recognized efficiency in farm works and importance of their health maintenance.

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An automatic support driver has been developed for the vinyl tunnel on widths and high ridgesd where the lettuce is planted in four rows. In this device, plastic tunnel support made by glass fibers was drawn out one by one, and it was driven into the ridge at a constant distance. The work efficiency was 1.0h/10a when the ridge width was 1.8m wide and working speed was 0.20m/s. The rate of driving miss was 0.6〜2.8%. The machine was considered to be good in practical use because the operating accuracy was fairly good.

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The objective of this study is to develop a grade and size judgment system of sweetpotato using a machine vision and neural networks algorithm. The judgment software was composed by video capture control, image processing, feature extraction, neural networks judgment and counting routines and it was developed using Microsoft Visual Basic. The shape of sweetpotato can be separated into two groups (long and round) by using the extracted entropy or Fere't ratio. As for sweetpotato grading, the network models consisting of 7 input units, 12/13 hidden units and 6 output units gave high recognition ratio for round and long shape, respectively. When the output of the combination of neural networks was compared to human classification, 86.1 % for whole shape correct classification was observed.

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Effects of growth retardants on the growth of Pelargonium×hortorum L. were investigated. Three growth retardants (uniconazole, chiormequat and paclobutrazole) were treated with two different concentrations by foliar spray. All growth retardants decreased stem length. Paclobutrazole by foliar spray was the most appropriate growth retardant for Pelargonium pot culture, although more detailed experiments may be required.

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