Agricultural and industrial wastes are global environment problem. The ashes of agricultural wastes like rice husk are recognized as having pozzolanic properties. In this study, many types of ashes obtained from agricultural and bio wastes, such as dead tree leaves (AML), waste cut grass (Korai, Tifton, native shiba), groundnut shell (GNT), wheat straw (WSI, WSJ), were evaluated for their possible pozzolanic potential. Many trials were made to determine the optimum burning conditions with respect to residue ash and carbon contents. Ashes then obtained were further investigated by Thermo-gravimetric analysis. X-ray diffraction analysis indicated that ashes obtained at 600°C/5hrs burning condition contained more amorphous matter than ashes obtained at 800°C/5hrs burning condition. Mineralogical analysis proved that AML, having high contents of calcium along with significant amount of silica, can be treated as high calcium ash. Ashes from Korai grass and native shiba have significant presence of silica and have the potential of a pozzolanic material.

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The behaviour of concrete using Fengzhen unclassified fly ash from China as a mixture of concrete was studied to verify the sulfate resistance. The results showed that the density of the specimens with unclassified fly ash was slightly lower than that of without unclassified fly ash, but the density significantly declined when AE agent was used. The order of the compression strength and dynamic modulus of elasticity of specimens at the age of 28 days was normal concrete>concrete with fly ash>AE concrete, while the order of the sulfate resistance was quite reversed. The higher compressive strength does not mean that it would be better in sulfate resistance. By this experiment, the effect of sulfate resistance of concrete with Fengzhen unclassified fly ash was ascertained.

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Bentonite is widely used for clay liner materials because of high swelling, low hydraulic conductivity, and the high sorption capacity of contaminants such as heavy metals. In this paper, batch sorption tests and selective sequential extraction tests were conducted to evaluate sorption capacity and forms for lead, using three types of bentonites from Japan and US with different physical, chemical, and mineralogical properties. Cation exchange and carbonate phase were predominant for the sorption of lead by bentonites; the carbonate phase was dominant at high equilibrium pH, while the cation exchange phase became dominant as equilibrium pH decreases. The ratio of carbonate phase was greater for the bentonite with higher amount of carbonate, so was the maximum Pb retained. The Japanese bentonites sorbed greater amount of Pb than the US bentonite as they contained more carbonate. The formation of cerussite (PbCO₃) primarily contributes to Pb sorption by carbonate, so does partially the formation of Pb hydroxycarbonatecomplexes.

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This study dealt with the influence of application the biomass charcoal to the Shimajiri-maji soil on sugarcane growth and nitrate nitrogen losses. Two kinds of biomass charcoals, biosolids and sugarcane bagasse, were incorporated into the Shimajiri-maji soil. Changes in concentrations of nitrate nitrogen in percolating water, specific gravity and available moisture of soil at before and after the experiments were observed. The index of the sugarcane growth, the stem diameter and length, Brix, sugar beet produced and root tension of sugarcane in each experiment were clarified.
The results indicated that the bagasse charcoal decreased soil hardness and increased available soil moisture in Shimajiri-maji soil. It became clear that maintaining the suitable soil water content have resulted in not only increased the yields but also increased the sugar contents of sugarcane. In addition, the concentrations of nitrate nitrogen in percolating water decreased. It may be concluded that the application of bagasse charcoal can reduce the environmental loads in the Shimajiri-maji soil.

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In this study, land use maps of Don Daeng village, one of the traditional villages in Northeast Thailand, were prepared by integrating long-term field surveys' data and information into the GIS database. The land use maps were prepared for four different periods: 1930s, 1960s, before 1980s, and 2005. The study showed that the total paddy field areas in the periods, 1930s, 1960s, before 1980s, and 2005 were 307ha. 5 l3ha, 543ha and 554ha, respectively. Paddy fi elds have expanded 1.8 times since 1930s. On the other hand, during these 70 years, almost all the forests have been cleared due to the reclamation of paddy fields. However, after 1980s, some of the paddy fields had been changed into meadows and fish farms in order to breed cattles and fishes, while other paddy fields remained expanding by reclaiming forests, vegetable farms and meadows. In addition, the study also suggested that the paddy fields have been spatially expanding towards the uphill (high-land) of the “Nong”, a concavity landform, and this local landform has been strongly influencing the expanding process of the paddy fields in the study site.

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Seepage failure is one of the most important problems associated with performance-based design of soil in high groundwater sites. Here, we discussed the movement of soil particles with increases in the up-and downstream hydraulic head difference H, during seepage failure experiments of soil within double-sheet piles, using PIV (Particle Image Velocimetry) analysis. The following conclusions were obtained:
(1) PIV analyses show movement of sand particles and boundaries between regions where soil particles do move or not.
(2) When H increases beyond H_d (≅H_y), downstream rise and upstream drop of the soil surface occur. PIV analyses show that soil particles move upward near sheet pile walls and upward toward the center of double sheet piles far from the walls. Hd and Hy are hydraulic head differences at an abrupt change in H≅Q₁₅ curve and at deformation of soil, respectively.
(3) The movement of soil particles is limited to approximately the depth D and width D/2, which proves the validity of Terzaghi's method and the Prismatic failure concept, where D is the penetration depth of sheet piles.
(4) The relationship of H_PIV≅H_d≅H_y is obtained, where H_piv is the hydraulic head difference at the start of soil particle movement using PIV analysis.

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A new relation, a non-dimensional thermal conductivity versus the degree of soil saturation with water, was developed for three Japanese soils of diverse textures: Toyoura sand, Red Yellow, and Ando. Estimated thermal conductivities follow closely the experimental data with a root mean square error of up to 0.1 W·m^-1 K^-1. The use of series/parallel model for predicting thermal conductivity at dryness and full saturation extends the application of the normalized thermal conductivity model to soils of different compactions. The developed model may also be applicable to soils having similar genesis and resembling texture characteristics to the soils under investigation.

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In recent years, it is stressed that rural residents need to reduce their dependence on the government and endogenously revitalize their communities while serious issues suchas depopulation, aging of the rural population and stagnation of economy are intensifying. This study seeks to devise a workshop method to support endogenous rural development. In this workshop method, a series of three workshops is offered to provide a place of learning for residents who will carry forward endogenous rural development. We applied this workshop method to 10 districts in Wakayama prefecture and verified its effectiveness. Participants in the workshops experienced three processes: 1) gaining awareness about the local problems, 2) recognizing structurally the features and problems of their districts, 3) generating ideas for revitalizing their communities, and evaluating the priority orders of the ideas. We found many changes in participants'consciousness and actions for regional development through the series of workshops. On the other hand, it was clarified that the workshop method needs to be improved in terms of, among others, work contents (complexity), participants'attributes (gender and age bias in participation).

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The study area is located at the southern part of Okinawa Island, Japan, where Ryukyu Limestone is extensively distributed. Nitrate concentrations at springs have been decreasing through a long-term monitoring since the mid-1990s. We studied the sources of nitrate in the groundwater by the emission factor method using data on the cultivated area, the number of livestock and the population. The result revealed that the trend of the nitrate concentrations corresponds only to that of the load from chemical fertilizer for upland fields, leading to the assumption that the chemical fertilizer most strongly affects the groundwater quality. The result of the balance analysis of water and nitrogen using a parallel reservoir model which takes into account cave systems supports this assumption. The calculated result by the nitrogen dynamics model that consists of the parallel reservoir model as a water balance submodel and a nitrogen balance submodel is coincident with the trend of monitored nitrate concentrations.

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Although rapid development in rural settlements in urban fringe areas has decreased, sprawl development is still progressing. As if it responded to this, the area of abandoned agricultural field is increasing. The ordering of land use is considered to give profound effects for farmland resource preservation of such areas. One of the means to orderig land use is to make practical use of non-agricultural land by land replotting system. However, since the land replotting is institutionalized inclusively with land readjustment under the present system, the repetition of land replotting is impossible unless land readjustment is performed simultaneously. In this paper, we discuss the function of land use ordering embedded in the repetition of land replotting through a case study of the “ Simplified Farm Land Consolidation Project ”, which is considered to be less bound by the institutional restriction. We also propose a land use regularization technique in the case of “ Simplified Farm Land Consolidation Project ”.

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We analyzed carbon stable isotope ratio (σ¹³C) of spiders (Arachnida) which were caught nearby farm ditches and a levee in a paddy field at hill bottom (katsuda) with their life types.σ¹³C of web-builder spiders was 26.0%0, which indicated that they have been greatly affected by insects emerged from the ditches that had depended on the organic matter supplied from village forest (Satoyama).σ¹³C and its distribution of long jawed water spiders (Tetragnatha maxillosa) was approximately equal to silver vlei spiders (Leucauge magnica). That suggested that both of spiders depended on the same food resources. Although σ¹³C of phytophilous hunting spiders was close to the web-building type, the standard deviation was higher than that.σ¹³C of epigaeic hunting spiders was 22.2%0, which indicated that C4 plants rose σ¹³C value of the spiders. It was suggested that σ¹³C of epigaeic hunting spiders lay in close relation with the rate of C4 plants to the hole plants on the levee and approximately one third of carbon in their bodies was derived from C4 plants. We revealed diversity of material flow in creatures by carbon stable isotope ratio in the area of Iatsuda ditches, which is the ecotone between Satovanur and a paddy field.

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Proper watershed water quality modeling is one of the most essential parts of watershed management. In this study, a water quality model was developed for the Cidanau watershed, Indonesia, and its performance was evaluated in view of the model's applicability to water pollution issues. The watershed water quality model consists of a subcatchments-based application of the tank model and water quality components. This type of modeling is considered as the most appropriate considering data availability and spatial variability. The LQ and the dissolution-type for the water quality components were employed, and the method of parameter setting based on grouping of the subcatchments was verified to obtain the best model structure. The established watershed water quality model was expected to perform as a simulation tool for identification of the influential factors in water pollution.

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A vertical one-dimensional diffusion model was applied to study formation and destruction processes in density stratification in Lake Koyama, Tottori Prefecture. In this model, a vertical eddy diffusion coefficient was dealt as the function for the local Richardson number, and for the parameters contained in this model, the optimum value for the water region was determined using a genetic algorithm. Using this model, we were able to effectively reproduce the observed results for temporal and spatial variations of water temperature and salinity. These results of numerical simulations indicated that thermal stratification occurred at wind speeds of 5 m/s or less, and that depending on the wind speeds, the position of the density interface changed within a scope of 1.5 to 3 meters. The wind drift time required for destruction of the strata was determined using an exponential function of wind speed. The factors resulting in progression of anoxia at a depth of 3 meters or more during the warming period in the summer where the maximum water depth was about 6 meters were examined based on the results of numerical simulations. Because the density interface is located at a depth of less than 3m at wind speeds of 4m/s or less, and because the compensation depth is about 2.4m, we can assume that progression of anoxia occurs at depths of 3m or more, because the oxygen consumption rate exceeds the oxygen supply rate in a day.

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