Development of the RTSS has continuously advanced since 1997 (Shibusawa et al. 1999), keeping up with the current trend of the Japanese model for precision agriculture. However, the RTSS had not yet been used to measure fields larger than 1 ha. We developed a technique using the RTSS for efficient soil mapping of large-scale farms. Specifically, we developed an arrangement of RTSS soil scanning lines most suitable for use in large-scale farming, and we developed a method of presenting the data predicted by the RTSS on a farm map.
Soil scanning lines for farm crop management were arranged at an angle to the transect lines customarily used with conventional soil sampling methods, and the whole surface of the farm was scanned by the RTSS. The soil scanning lines for site-specific crop management followed the same intervals as a constant-width sprayer. The farm map is a grid-based map, which the grower can easily understand. A feature of the grid-map is that each grid cell shows the mean value, the maximum value, and the minimum value of various soil parameters.
The main improvement of the RTSS was made by doubling its customary speed to 0.56 m/s. We used partial least squares (PLS) regression techniques to analyze the change in the sensitivity of the calibration curves due to this increase in speed. The coefficients of determination (R²) between the values of parameters calibrated by the RTSS and measured values of soil samples were 0.77 for moisture content, 0.49 for soil organic matter, 0.53 for pH, 0.86 for total nitrogen, and 0.95 for total carbon. Owing to analysis error, the nitrate nitrogen data for many of the soil samples had to be omitted; therefore, the grid-map of nitrate nitrogen is shown for reference only. R² was 0.09 for nitrate nitrogen.
By such an increase in speed, RTSS scanning can now be carried out at 1 ha/h for large-scale farms. In this study we scanned 11 ha spread over four farms.
The best result from this study was that a grower was able to confirm from the pH grid-map an area where a large quantity of lime had been accidentally spilled in the past. Consequently, the grower accepted RTSS as a tool to assist him in making decisions.

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Gentian (Gentiana spp.) is one of the most important floriculture crops grown in Iwate Prefecture, and production has steadily increased. They are generally used as cut flowers, but the flowers gradually deteriorate after being harvested. Because the commercial value of the flowers decreases as they deteriorate, discrimination of the growth stage can be an effective method to select flowers that will stay fresh as long as possible after being harvested. To date, however, no technique has been developed to discriminate the growth stage of gentian flowers. By examining the corollas of gentian flowers, we found that the spectral radiance of older samples was lower than that of younger samples in wavelengths between 700 and 900 nm. In this paper, we attempt to distinguish the growth stage of gentian flowers by measuring the pixel values of their corollas in ultraviolet images. The pixel values in ultraviolet images increased remarkably when the inner pollen was mature and had just begun to disperse. The pixel values decreased after this stage, possibly because the corollas were damaged by insects attracted to the pollen. We were thus able to use ultraviolet images of gentian flowers to determine the growth stage of gentian flowers and identify the best harvest time, which is before the plants are damaged by insects attracted to the pollen.

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The goal of this study is to develop an approach to determine the internal qualities in oil palm (Elaeis guineensis Jacq. var. tenera). Bunches and fruits belonging to 4 classes of ripeness (overripe, ripe, underripe and unripe) were used for this study. For these bunches, three of internal qualities as ripeness, oil content and free fatty acid content were examined. Since the estimation of internal qualities based on the overall data for a bunch was difficult, we focused on the average reflectance and the average relative reflectance values of fruits that were not concealed by fronds in bunch. By our approach, it was necessary to estimate the ripeness of the bunch before the oil content and free fatty acid content were determined. To classify ripeness of a bunch, the average relative reflectance values of bunches in different classes of ripeness were used and classified based on Euclidean distance. In addition, ratio of chlorophyll to carotenoids (R_p) was also used for estimating ripeness of a bunch. Then oil content (OC) and free fatty acid (FFA) content were predicted by calibration models corresponding to the class of ripeness. Correct estimation results in all classes of ripeness were obtained by both methods. The coefficients of determination (R²) were 99.7% and 99.5% with a standard error of prediction (SEP) of 0.421 and 0.190 in the validation of oil content and free fatty acid models, respectively. For oil palm fruits, methods to estimate the ripeness of the fruits were developed. Ripeness estimation using the average relative reflectance values in lower part of the fruit was compared with ripeness estimation using the ratio of a not-pale greenish yellow area, a not-yellow area and a not-reddish orange area to the entire area of fruit. The correct estimation in all classes of ripeness was obtained by using the average relative reflectance at lower part of fruit while a correct ripeness estimation rate of 97.92% was gained by using ratio of area in fruit. Since the ripeness estimation using the ratio of the area of the fruits can be done automatically, it may provide more practically applicable for the assessment of fruit ripeness in the factory.

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We proposed an energy flow model using multiple types of biomass to conduct a system dynamics analysis of the potential of using bioenergy as an alternative energy of fuel for automobiles in rural areas. Six scenarios for Tochigi Prefecture, Japan, as one example of energy self-sufficient society, were proposed for simulations based on the energy flow model. The scenarios included the use of unpractical and unused farmland for biomass production and the diffusion of electric vehicles (EV) in Tochigi Prefecture. Simulation results showed that sufficient bioenergy could be produced after 27 years to satisfy the requirements of alternative energy automobiles under the following conditions: a 5% annual EV diffusion rate, a 2.9% annual improvement in fuel consumption for both EVs and gasoline vehicles, and a 4.2% annual increase in the area of unpractical and unused farmland used to produce feed rice (Fukuhibiki) as biomass. Fuel consumption rates and the diffusion rate of EVs strongly affect the outcomes of the simulations.

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Eco-feed is an animal feed produced from the byproducts of food processing industry, and from food waste from restaurants. The use of eco-feed has gained greater attention as concerns about resource sustainability and Japan's low self-sufficiency rate in animal feed have increased. Although the use of eco-feed may help increase farm profits, it could also decrease the price of the meat relative to that of hogs raised on standard feed. This study analyzes consumer evaluations of pork from hogs raised on eco-feed using a stated preference method. The eco-feed-fed pork was negatively evaluated by some consumers, especially those who were reluctant to try it. On the contrary, the pork received positive evaluations from those who stated they were interested in recycling food, and from people with high incomes. To enhance the use of eco-feed at farm level, it is necessary to inform consumers that the quality of eco-feed is ensured and the use of eco-feed will help Japan achieve a sustainable society.

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