To reduce the amount of labor needed for harvesting vegetable jute, its growth habits were investigated by conventional cultivation methods. The combined marketable yields over the 50-day period were 629.1 branches/m² and 3, 659g/m², although a high branch density made cutting difficult in the preceding harvest. Total yield mainly consisted of the primary, secondary and third branches, whose yield peaks occurred at about 4-week intervals. The yield fluctuated at each harvest time. After harvesting the primary branches, the weights of all the other branches were about the same. Harvesting required time for the movement of scissors and time to check the branch lengths and the number of knots. To resolve these problems, a study was conducted to examine the effects of training the branches to grow in different configurations. By training the primary branches to grow horizontally and the secondary branches to grow vertically after pinching the trunk at 20cm above the ground, the marketable yield per area increased by 6% and the work time per area decreased by 17%. This method confined the cutting position mostly to a single plane and improved the efficiency of light reception. In addition, stem hardness was less than that obtained with the conventional pinch method.

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The purpose of this study was to develop a program which traces movements of a person engaged in farm work making use of image processing technology. This has been carried out as one of the studies on workstation for an autonomous bio-production robot. This paper deals with the development of a program by which indoor movements of a person were traced while the background was clearly distinguished. This study was in analysis preparation phase, and the outcome will be applied to every activity conducted in an agricultural setting. It was revealed that the developed program thus was capable of detecting movements of a person extremely accurately though it was somewhat affected by noise due to reflection of indoor fluorescent lamps.

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As part of our research project on visual recognition of an autonomous agricultural tractor, we developed an image processing program that can detect on a real-time basis the movements of both tillage and no-tillage portions of an experimental field plowed by the tractor. Recognition is based on animation images taken by a video camera. Our analysis of static images, done for the purpose of verifying the reasonableness of parameters set to analyze animation images, allowed boundary regions to be recognized very clearly. The processing took about 0.1 second per static image. Analysis of animation images brought satisfactory field recognition results in both fine and cloudy conditions. Thanks to the use of algorithm incorporating the concept of region growing, our program was able to process animation images as fast as about 0.2 second per frame even for images taken in cloudy conditions, which have been difficult to recognize with traditional techniques.

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In order to establish fully automated pest control in a greenhouse, the authors developed a spraying vehicle that travels along furrows. Since a power sprayer mounted on the vehicle is driven by a gasoline engine, plants in the greenhouse might be injured by exhaust gas. Gasoline exhaust contains ethylene. Ethylene is one of the plant hormone that makes plants shed their flowers and buds. The objectives of this study are to clarify the effects of ethylene contained in the gasoline exhaust on the shedding of flowers and buds of plants grown in greenhouse, and to determine a countermeasure against shedding.
1. In a closed vinyl house, the engine was operated for 5 (high ethylene concentration) and 2.5 (low concentration) minutes. Potted sesame and sweet pepper plants were exposed to the exhaust gas for 2, 4 and 12 hours. The longer the fumigation time the more flowers and buds were shed. However, flowers and buds increased when plants were fumigated for 2 hours in either concentration.
2. In a closed or partially opened vinyl house, the engine was operated for 5 minutes and potted sesame plants were exposed to the exhaust gas for 12 hours. In the closed vinyl house, ethylene concentration was 0.75ppm even 12 hours after the engine was stopped, and flowers and buds were shed markedly. In contrast, in the partially opened vinyl house, ethylene concentration decreased to 0ppm 3 hours after the engine was stopped, and neither flowers nor buds were shed.
As mentioned above, it was revealed that shedding of flowers and buds caused by ethylene contained in the gasoline exhaust could be prevented by providing suitable ventilation.

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