In Japanese highly intensive pig production areas, the amount of nitrogen from manure exceeds and it results in serious environmental problems such as water pollution by nitrates and gaseous ammonia emissions. Although reduction in crude protein (CP) in diets is a procedure to decrease nitrogen excretion, some literatures indicated that it might lead to increase back fat thickness in carcass. In this study, a model was developed especially to investigate the effects of CP contents in diets on the utilization of nitrogen by growing and finishing pigs and their back fat depth. First, the nitrogen balance was calculated on the daily basis as the difference between nitrogen intake and retention, and then accumulated during growing and finishing period (body weight of 30 kg to 105 kg). The two indices used as a measure of the environmental load in this study were total nitrogen excretion / total nitrogen intake (I₁) and total nitrogen excretion / total nitrogen retention (I₂). The different simulations showed that decreases in I₁ and I₂ resulted from reduced CP contents in diets, when feeding levels are moderate and high. Remarkable decreases of back fat thickness in carcass were achieved, when feeding level was low. The results also suggest that the effect of CP content in diets on environmental load and production could vary widely according to energy contents and feeding levels.

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From the point of view of the sustainability of agriculture and food production, it is important to lighten the environmental load by nitrogen and to utilize effectively organic wastes as organic resources in order to construct a recycling-based society. This study focused on regional level, for example city or town boundary, as a unit of the circulating system of organic resource. It investigated the exhausting circumstances of organic wastes in Ayabe city area, Kyoto, and tried to consider possible ways to recycle organic resources in order to come up a social system of resource circulation type. Nitrogen flows was estimated from 1979 to 1998 based on official statistics and survey data. The results are as follows; when present chemical fertilizer and all of agricultural by-products are thrown in farmland, the nitrogen amount to apply in farmland are increased. The production of livestock excreta and food wastes were largely increasing for the last 20 years, and each growth rate is higher than Japanese national estimates. Especially the increasing trend of estimates of food wastes accelerated in recent years. Furthermore, it became clear that nitrogen flows in the region were increasingly caused by forage feeding rather than by chemical fertilizer input. We estimated that, if livestock excreta, food wastes and human waste are usefully recycled as organic resources, nitrogen waste to environment will be reduced by about 40 percent and uses of chemical fertilizer will be decreased by about 50 percent from the present levels.

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A potential change in climate will increase the number of extreme events. Such events may cause natural disasters and severely affect human lives and agricultural production worldwide. Remote sensing technologies have enabled rapid collection of data on natural disasters where contemporaneous field observations are unavailable or incomplete. We focus on satellite remote sensing based approaches to monitor environmental disasters and outline methods to detect events and evaluate the damages caused by them. These disasters include drought, flood, fire, volcanic activity, landslide, storm and cool-summer damage. The occurrence of a drought can be predicted from a combination of some indices based on the satellite remote sensing data and meteorological data. Flood, fire and volcanic activity can be distinguished easily from the remote sensing image based on the salient characteristics of spectral reflectance or the backscattering coefficient. However, many problems remain as to how to effectively predict a disaster and avert its damage before the disaster actually occurs, using a combination of remote sensing techniques, geographical information system (GIS) and administrative frames.

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We examined the degree to which we could distinguish paddy field use type in mountainous regions using high resolution image data from the IKONOS satellite. There were four use types: rice crop planted fields, upland crop planted fields, fallow fields, and abandoned fields. We distinguished field lot use type using supplementary data of the field lot boundary, based on digital ortho images from aerial photographs. That is, we first classified the pixels inside the paddy field area of the satellite image using the supervised classification method. Next, we distinguished the use types by consolidating the classification results for each field lot. The overall distinction accuracy was 87%, and the average distinction accuracy was 72%.

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