Today in this country, we are concerned about the effect of acid precipitation on soil, and therefore some measure for quantitative future prediction is required. In this paper a numerical model to calculate historical change of chemical characteristics of soil at forested sites based on the assumption that acid precipitation is neutralized by cation exchange reaction and chemical weathering in soil is constructed, and the method to estimate chemical weathering rate by using the model is proposed. In this method, the assumption that acid precipitation was neutralized by only chemical weathering in the past when the effect of human activities on chemical species in rainwater and atmospheric trace materials were negligible, and the chemical weathering rate is estimated with the rule of trial and error by using the condition that the calculated chemical characteristics of soil coincide to the observed values. The application of the method to a bamboo forest in Osaka University Campus and the sensitive analysis of model parameters show that the method to estimate chemical weathering rate, proposed here, does not give remarkably different future predictions when model parameters are changed within their estimation errors with a few exceptions, and the method is considered to be a effective measure. In the application, chemical weathering was prevailing in acid neutralization in soil compared with cation exchange reaction, and the importance of the estimation of chemical weathering rate in future soil acidification prediction is suggested.

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This study aimed to forecast the future of international negotiations on the climate change problem by extracting negotiators' prospects on this matter . A new survey method, "3-step scenario framing survey, " was designed by the author to acquire comparable estimation of the negotiators in each country, as well as to be able to integrate their responses into one or two streamline scenarios . Predictions of the respondents converged into two independent negotiation scenarios, namely "developed countries and developing countries coordination scenario" and "technology development in the developed countries scenario." The former expected political role of the developing countries to be the driving force of the negotiation. It considered joint implementation or tradable permits system to be the key to mitigate global greenhouse gas emissions. Distrust of the developing countries toward devel oped countries was considered to be the crucial obstacle hindering implementation of such measures. The latter expected technological development mainly in the developed countries to be the driving force of the negotiation. The developed countries were to take lead in the negotiation to win agreements that would advantage their technology. The major problem within this scenario was that the developed countries have no incentives for to transferring their technologies to other countries, which may be solved by establishment of institutions for such transfer.

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The aim of this research is to develop a utilization system without generating pollutants different from waste disposal and burning treatment by separating the biomass such as rice straw, waste wood, bark, and others into structural components using physical and chemical pretreatment, i.e. steam explosion and by conversion into useful materials. An effective process consisting of steam explosion, enzymatic sac charification, alcohol fermentation, methane fermentation, and resinification could completely convert the components of rice straw into useful materials. Rice straw was treated under various explosive conditions such as steam pressure and steaming time; the exploded rice straw was separated into water soluble material, a mixture of cellulose and low molecular substance, methanol soluble lignin, and Klason lignin. The effects of steam explosion on the characteristics of the exploded rice straw were studied experimentally for particle size distributions, productions of organic acids, and amounts of extractive components. Steam explosion could separate and depolymerize the lignin in the rice straw, causing the enhancement of the susceptibility of holocel lulose to the enzymatic saccharification and alcohol fermentation. The holocellulose in the rice straw exploded at a steam pressure of 3.53 MPa and a steaming time of 2 min was efficiently converted into energy resources such as ethanol and methane by the operations such as saccharification and fermentation, and the methanol soluble lignin was converted into an excellent thermosetting resin by the epoxy reaction.

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A diaphragm-glass electrode method was applied to measure CO₂ concentration in soils in a Japanese cedar forest at Isehara City. A continuous measurement throughout a year at a fixed depth of 80 cm showed that the seasonal variation of CO₂ concentration was generally attributable to that of ambient air temperature inside the forest. In summer with water famine, however, CO₂ concentration decreased dramatically from 4.75% in July to 1.84% in September. This was probably caused by the expansion of air pathways to the atmosphere as well as the decline of biological activity. Spatial variation of CO₂ concentration was relatively large. Even at a constant depth (50 cm), CO₂ concentration ranged from 0.71 to 2.53% at 5 points allocated at 2-4 m intervals. CO₂ concentration was higher in deeper soil horizons throughout a year. The primary advantages of the method are (1) it enables an automatically continuous measurement of CO₂ concentration in soil air, and (2) it consumes a quite small amount of CO₂ and hence it enables a pinpoint CO₂ measurement. The disadvantage of the method is related to a bias from actual CO₂ concentration . This may be caused by (1) the turbulence of soil horizons in the observation hole due to a periodical calibration of the electrode, and (2) the difference between air temperature on the ground, where calibration is carried out, and that in the soil of interest. The percentage of the bias in the latter case was estimated to be lower than roughly 15% .

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