This study was conducted as a first step in the development of the robotic harvesting system for eggplants. The robotic harvesting system with hand-eye structure was fabricated and the visual feedback fuzzy control model to operate the manipulator was developed. The control model was examined in terms of manipulator guidance to the fruit, estimation of the fruit maximal diameter for selective harvesting and estimation of the fruit angle for the picking movement. From the results of the approach experiment, the control model enabled the manipulator end to reach a fruit 300 mm away with 6 to 10 feedback signals. The manipulator trajectory varied in vertical direction with fruit location and the control model actuated the manipulator end slightly upward than the target region. The control model could estimate the fruit maximal diameter with an accuracy of 29.0±17.9%. However, it still has a low standard of performance as a visual sensor for selective harvesting. Moreover, it could estimate the fruit angle in row direction with an error of 3.6±2.60. The visual feedback guidance ot the manipulator was confirmed to be an effective method for a robotic eggplant harvesting.

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Development of an effective, high-power, low-cost, artificial light source for use in plant-growing facilities would be very beneficial for plant production.
Recently, the laser-diode lamp has been proposed as a new type of light source for plant production. The advantages of the laser-diode lamp over conventional light sources are its high electrical-to-optical power conversion efficiency, low thermal radiation, easy set-up for high power and pulse irradiation, small weight and small volume for mounting, and selectivity for proper wavelength.
Because laser light itself differs from the light sources presently used in plant growing, we confirmed the possibility of growing plants under the laser-diode light by growing lettuce
(Lactuca sativa L.) plants.Lettuce seedlings with 5-6 leaves were grown under a laser-diode lamp panel with 30 pieces of high-power and high-efficiency AlGaInP laser-diodes. The power of each laser-diode lamp was 500 mW, and the wavelength was 680 nm, which was efficient for photosynthesis.
The lettuce plants were able to grow under the laser-diode light. However, the weight of the lettuce plants grown under the laser-diode lamps was light, and their leaves were long and thin compared to those of lettuce plants grown under high-pressure sodium lamps.

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The LISA (Low-Input Sustainable Agriculture) program was launched to reduce the use of off-farm inputs with the greatest potential to harm the environment or the health of farmers and consumers. This is one of the operational definitions of sustainable agriculture. However, LISA has not gained appreciable support from the agricultural sector, since the nature of LISA decreases profits. On the other hand, the implementation of Precision Agriculture (PA) has been embraced. The difference between PA and LISA is that PA requires technological innovation, whereas LISA always involves revising or improving traditional practices. The extensive application of information technology, including GPS and GIS, to agriculture, and the development of agricultural machinery for PA are major factors for the difference between PA and LISA. The machinery includes equipment to implement variable rate technologies, and vehicles specifically designed to gather the information required to generate yield and soil maps.
There are quite a few plant factories operating commercially in Japan. PA is nothing but integrated technology, designed to optimize the cultivation process. The fully controlled environment of a plant factory can be considered as an ideal cultivation system in terms of alternative agriculture. Most of the environmental factors in a fully controlled plant factory are observable and controllable; a plant factory can be optimized more easily than an open field. Microprecision agriculture can be attained by using plant factories to realize profitable alternative agriculture. This article reviews the scientific and technological achievements of plant factories as alternative agriculture, and introduces a hardware system developed to implement microprecision agriculture in a plug seedling production factory.

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Cucumber plants were grown in a closed system of rockwool hydroponics. Nutrient solutions were supplied at constant volume at three different nitrogen levels (4, 13, and 22 me·liter^-1). Phosphate, potassium, calcium and magnesium levels in the solution were 3, 6, 7 and 4me·liter^-1, respectively.
At the low nitrogen level, plant growth was delayed and concentrations of elements in leaves were low. At the intermediate nitrogen level plant growth and yields were the best, while at the high nitrogen level they were low compared with the lower nitrogen level.
At the intermediate nitrogen level, accumulation of nitrogen in the nutrient solution occurred slightly only at the last growth stage. At the high nitrogen level, its accumulation occurred intensively from the middle growth stage onwards. With both levels, accumulation of other elements was not different; accumulation of calcium, magnesium and potassium occurred from the first stage, from the middle stage and at the last stage, respectively. Phosphate concentrations in the nutrient solution were almost zero after the first harvest.
Foliage nitrogen concentrations 50 days after transplantation were high only on the upper nodes of plants grown at the intermediate nitrogen level but both on the middle and upper nodes at the high level. Phosphate contents were correlated with the nitrogen levels in the nutrient solutions and increased in leaves on the more upper nodes as well. However, calcium and magnesium contents decreased in the leaves on the upper nodes, and they were also lower at the high nitrogen level in accordance with their accumulation in the nutrient solution. Potassium contents showed a similar trend to that of calcium in leaves on the middle and upper nodes. These findings revealed that for the closed hydroponics system the nutritional balance in the nutrient solution must be changed for different growth stages.

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There are two methods of making a general nutritional diagnosis of plants. One is a visual diagnosis based on experience, and the other is a sap analysis of a stems and leaves. Many years of training and experience are needed to make a visual diagnosis, whereas the chemical analysis of a sap also takes a long time to obtain results.
Therefore, we have studied the relationship between leaf electric potential and the nutritional condition of plants. We found that the inorganic nutritional condition (N, P, Mg) of a tomato can be diagnosed by examining of the three dimensional distribution of three alternating current components (30.0, 13.0 and 20.0Hz) of leaf electric potential.

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In Akita prefecture, cherry bark is used for traditional industrial purposes (so-called kabazaiku). It is basically necessary to evaluate the bark of the tree for breeding and silviculture.
In the present study, we established a bark evaluation method that can be used with ease. From the observation of 3 mountains with cherry tree growth, it was seen that the cherry trees located on the ridge side were shorter and had smaller diameters and thiner bark compared to those on the valley side.
Using principal components analysis, the bark from 8 locations of 3 mountains could be classfied into 4 types. Moreover, the cherry tree height, bark thickness, and healthiness are correlated to the diameter of the tree. The height and the bark thickness can be estimaed by a single regression formula, using the tree diameter as the explanatory variable, but the bark healthiness cannot allow such estimation.
It was suggested that the cherry bark thickness and the healthiness are genetically and environmentally regulated.

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Along with the development of simulation software using results of prior research that showed environmental control conditions and air-conditioner operating conditions, this study pursued perfect environmental controls for mushroom cultivation rooms in a standard-sized 150, 000 cultivation mushroom facility (Nagano City) to clarify the actual conditions of the cultivating environment.
1. In mushroom cultivation rooms, the carbon dioxides produced by mushrooms is diluted by outside air, and therefore, due to this introduction of outside air, the room environment becomes unsuitable for a brief 1-2 minutes in the early afternoon during the summer, and for 2-5 minutes at daybreak in the winter. Accordingly, adjustments to the carbon dioxide concentration through the cultivation of other vegetables in the same room and the reduction of facility investments become important considerations.
2. When a 0.5 m³/s ventilation fan and a 21 kW cooling unit were used, it was possible to control the cultivation room's carbon dioxide concentration (4352, 4468, 4585) ppm, its temperature (21.7, 21.9, 22.0) °C, and its humidity (98. 0, 99. 3, 100. 0) %. However, a humidifier was unnecessary, When a 0. 5 m³/s ventilation fan, 21 kW cooling unit, 6 kW heating unit, and a 19 kg/h humidifier were used, it was possible to control the carbon dioxide concentration in the same satisfactory manner. In this instance, if the cooling unit was not used, the temperature would slightly exceed the desired control maximum (approx, 0.2°C, 3-4min/h).

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Carotenoid pigments of carrots were determined using high performance liquid chromatography (HPLC). Phytoene, phytoluene, ζ-carotene, α-carotene, β-carotene and xanthophylls were detected. β-carotene was predominant in the carotenoid. Carotenoid concentrations were higher in the cortex compared with those in core tissue. The highest β-carotene concen-trations in the cortex were observed in 'MK-D 548', 'Red Prince', 'Yosyu Gosun' and 'Hamabeni No. 2' in that order. A high correlationship was noted between β-carotene and a value in the culitivars.

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