Polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofruns (PCDF) are groups of compounds (named dioxins) and seven PCDD and 10 PCDF with chlorine substitutions at the 2,3,7 and 8 positions are considered toxic. The public has been concerned about human exposure to PCDD/F from contaminated animal food products. This paper discussed possible dioxin exposures to beef using wide-ranged literature values. This survey showed that, in Japan, high levels of concentrations of dioxins in ambient air were found in industrial and urban areas due to many municipal wastes solid incinerators, and those in soil in rural areas due to intensive use of herbicides. Concentrations of dioxins in Japanese beef were compatible with other literature values in other countries. In the future, systems approach based on comprehensive researches and collecting data will be required to identify and resolve the major problems for dioxins.

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A model for predicting concentrations of polychlorinated dibenzo-p-dioxins and fruns (PCDD/Fs) in beef was developed and used to examine effects of concentrations of PCDD/Fs in air and soils and feeding strategy (ratio of roughage in feed) on concentrations of PCDD/F in beef. This model was constructed based on pathways involving air, soil, plant feeds (concentrates and roughage) and cattle. Three important pathways for accumulation of PCDD/Fs in plant feeds were atmospheric deposition, root uptake and air to leaf transfer. Beef biotransfer factor (BCF) was used to predict accumulation of PCDD/Fs on beef. The predicted dioxin (PCDD/Fs) in beef was 0.118 pgTEQ/g, when Japanese environ- mental situations and feeding strategy were assumed (dioxin concentration in air, 0.06 pgTEQ/m³; dioxin concentration in soil, 40 pg TEQ/g; housed feeding; ratio of roughage, 10 %). The simulation results using the model showed that higher concentrations of PCDD/Fs in air and soils increased concentrations of PCDD/F in beef. Cattle on high roughage feed produced higher contaminated beef.

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Penalized multiple linear regression is applied to constructing additive model which handles predictors represented as distributions. A subroutine "dsnsm.f" included in GCVPACK carries out this numerical computation. This method leads to an additive model to estimate rice yield (kg/10a), in which predictors consists of harvest year and a distribution of daily average temperature. The additive model is proved superior in terms of GCV (Generalized Cross-Validation) to the one in which average of the distribution is a predictor.

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Nitrogen related oxides are considered to be a major source of substances related to acid rain and possibly the global warming. To evaluate the dynamics of these substances in river basin environment, a quantitative assessment of the land cover and its change is necessary. In this study, multi-temporal satellite data and the forest records were utilized to classify the land cover, particularly the forest vegetation distribution, of a mountainous region featured with frequent change in terrain and with a great coverage of forest vegetation located within the Nagara river basin. The influence of shadows caused by ruggedness in terrain was reduced by ratioing the radiance among several differential spectral bands (Band 5/Band 1, Band 4/Band 1). The difficulty in distinguishing certain categories of land coverage, a negative effect brought about by uniformization of the radiance with ratioing, was alleviated by composing a new color image from both the image after ratioing treatment and that of Band 3. Through analyzing the newly composed color image and the original image of two different seasons, the forest vegetation was classified into four forest types, namely, the evergreen coniferous forest, the evergreen broad leaved forest, the deciduous broad leaved forest and the mixed forest. The evergreen coniferous forest was further divided by age into the following four different groups: a group under 20 years, a group from 20 to 35 years, a group from 35 to 65 years and a group above 65 years. The reliability of the classification was confirmed by comparing the obtained results with related census data. In addition, the change of the land coverage of this region with time was also examined by using two satellite data with a time interval of 20 years.

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Diurnal courses of photosynthesis and transpiration were measured on rice leaves within the same height range and with four different azimuth angles (leaf orientation; east, south, west, north) by the closed chamber method in the field. Diurnal courses of photon flux density (PFD) on leaf surfaces were quite different among the four leaf orientations. Accordingly, diurnal courses of leaf photosynthesis also differed with the leaf orientation. However, in most cases, significant difference in the relationship of PFD on leaf surface and the leaf photosynthesis (light-photosynthesis curve) was not found among the four leaf orientation. Stomatal conductance gradually decreased from the morning to the evening, and did not show any appreciable difference among the four leaf orientations either. Daily total PFD on the surfaces of east-, west- and north-oriented leaves were about 37 %, 28 % and 80 % lower than that on the south-oriented leaf, respectively. An estimation showed that daily carbon gains on east-, west- and north-oriented leaves were about 20 %, 3 % and 36 % lower than that on the south-oriented leaf, respectively. On the contrary, daily water consumptions by transpiration of east-, west- and north-oriented leaves were similar to that of south-oriented leaf (ranged between 0.9 and 1.1 times). The present study therefore suggests that, the diurnal course of leaf photosynthesis is mainly subjected to the microclimatic PFD value (PFD on leaf surface) and its diurnal course, and is changeable with leaf's orientation and inclination, which affects the amount of daily leaf assimilation, whereas stomatal aperture and water consumption are comparatively uniform and not largely affected by the leaf orientation in the canopy.

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In China, the demand for beef has rapidly expanded in recent years due to increasing income according to the economic growth, the prevalence of Western lifestyle and the diversification of eating habits. However, the increase in beef production is involved in the emerging issues in terms of the food crisis since a large amount of cereals are necessary for beef cattle production. This study analyzed the present conditions of meat production in modern China based on statistics, especially focusing on beef. As a result, it was found that there was a high correlation of r=0.996 between GDP and beef production. Furthermore, this study also analyzed tastes for meat and tendencies of meat consumption in modern China by questionnaire. As a result of the questionnaire conducted in Beijing, Wuhan and Chifeng, tastes for meat and tendencies of meat consumption were different in these three cities, reflecting the local life, climate, culture and history. In addition, it was found that foreign food culture was prevailing the most in Beijing, the capital of China. It should be noted that the demand for beef in China will increase since most of the respondents showed willingness to increase beef consumption while beef, which is relatively expensive, was still not recognized as daily food. As for Shimofuri beef, which is well-known as high quality marbled one in Japan, the respondents who were "willing to eat Shimofuri beef" were a little more than those who were "not willing to eat Shimofuri beef" in these three cities. It is necessary that beef production systems suitable for China should be established since the increase in beef consumption in highly populated China would have a great influence on the world market of cereals.

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The soil is most important factor of the natural resource as it is directly related to food production in Asian countries. The soil types such as Oxisols and Aridisols peculiar to tropical region are distributed widely in Asian countries where Soil Taxonomy was adopted for soil classification. The computerized soil information system is useful to understand the present soil nature on a national scale. The computerized soil information system based on the Soil Taxonomy classification system was developed at the Bureau of Soil and Water Management (BSWM), the Department of Agriculture, Philippines. This system have several functions, which are to be easy to enter large amount soil data, to update, to retrieve soil data and to make interpretation data for different users, and to able to create digital soil map with topographic information (road network, contour etc.), and to output interpretation map such as pH distribution map and to make three-dimensional soil map with contour. Manipulation of the tabular soil database is done using programs written the FOXPRO programming language while the manipulation of the spatial component (maps) can be done in the GIS software. This system can spread to other Asian countries where Soil Taxonomy was adopted. Soil condition of other countries will be discussed between scientists through this system.

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Using administrative data and a pollutant load factor method, we estimated the amount of nitrogen load generated in the basins of the Chikuma and the Sai in Nagano during the past 30 years. Total amount of nitrogen load generated in the basins was 22,000 - 25,000 ton N yr^-1, in which the waste from livestock was greatest, followed by residential wastes and nitrogen leached out from farmland. Nitrogen derived from livestock and farmland gradually decreased due to the decline of those activities. The amount of chemical fertilizer consumption drastically decreased from 1980, and fell short of agricultural nitrogen demand calculated by using standard application rates for crop plants. It was assumed that the nitrogen shortage was compensated by livestock waste. Due to the reduction in chemical fertilizer use coupled with recycling of the livestock waste and the construction of sewage system, the nitrogen load entered into the rivers has decreased by 40% in the middle of 1990s. In order to make further reduction of nitrogen load into the rivers, it might be effective to increase the treatment efficiency of sewage treatment plants and to reduce the nitrogen leached out from agricultural area.

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