Tsuyoshi MIYAZAKI | The University of Tokyo (original) (raw)

Papers by Tsuyoshi MIYAZAKI

Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, Oct 25, 1996

The existing empirical, approximate, analytical, quasi-analytical and numerical solutions for pre... more The existing empirical, approximate, analytical, quasi-analytical and numerical solutions for predicting time to ponding (tp) were reviewed and compared in this paper. The quasi-analytical solution can provide a rough range of tp. As it is not confined to any special soil physical property,

Journal of the Japanese Society of Soil Physics, 2004

This study evaluated the performance of a rainwater utilization system. Excess rainwater is drain... more This study evaluated the performance of a rainwater utilization system. Excess rainwater is drained from rooftops into an underground container from which the water infiltrates from the base and sides into the surrounding soil of a vadose zone. The saturated hydraulic conductivity of the soil where this system was used was very low at the surface and higher in the deeper layer where the container was located. A simple method was proposed to estimate the steady recharge rate of excess rainwater from the buried container into the surrounding soil of the vadose zone. By modifying the steady recharge equation, which is widely used in the theory of the Guelph Permeameter, a steady recharge rate from the container was calculated from the measured value of saturated hydraulic conductivity and the size of the container.

Journal of the Japanese Society of Soil Physics, 2003

Zero flux plane (ZFP) method has been used to measure and estimate the evaporation, evapotranspir... more Zero flux plane (ZFP) method has been used to measure and estimate the evaporation, evapotranspiration, some hydrological process etc. However, no systematic discussion has been made concerning the ZFP method itself or its application to monitor and control the salt and contamination movement. In this study, comprehensive analysis on existing data sets have been performed to examine ZFP method applications and to give comments for further applications in future. First, ZFP method definition and its mathematical derivation were stated. Second, the application of ZFP to evaporation, evapotranspiration and ground water recharge process were discussed and analyzed. The di$culties that a#ect the application of ZFP method such as depth of soil, preciseness of measurements etc. have been listed and compared. Finally the potentialities of ZFP method were discussed. The discussion showed that, the development of new techniques related to measurement instruments, required experiments and simulations to implement ZFP in e#ective way is very important to monitor and control salt transportation and accumulation control.

TRENDS IN THE SCIENCES, 2018

Books in Soils, Plants, and the Environment, 2005

Paddy and Water Environment, 2009

The causes of soil alkalinization in the Songnen Plain of Northeast China were mainly analyzed fr... more The causes of soil alkalinization in the Songnen Plain of Northeast China were mainly analyzed from two aspects, natural and anthropogenic. Natural factors of alkalinization are parent materials, topographic positions, freeze-thaw action, wind conveyance, water properties and semi-arid/sub-humid climate. Some of them were always being neglected, such as freeze-thaw action and wind conveyance. Anthropogenic causes are mainly population pressure, overgrazing and improper agricultural and economic policies. In recent decades, overgrazing played a main role in secondary soil alkalinization, which led to the decline of Leymus chinensis grasslands. Now, the alkalinization is very severe, and more than 3.2 9 10 6 ha area has been affected by salt, which becomes one of the three largest sodic-saline areas in the world.

Open Journal of Soil Science, 2011

Soil column experiments and modeling investigations were performed to study the behavior of shall... more Soil column experiments and modeling investigations were performed to study the behavior of shallow water table in response to various recharge events. Hence, shallow water table fluctuations inside sandy (Toyoura sand) and clayey (Chiba light clay) soil columns in response to surface and sub-surface recharge events were investigated under laboratory conditions. Experimental results showed that small application of water could raise the shallow water table level more than 100 times in depth in the case of Toyoura sand and more than 50 times in the case of Chiba LiC, reflecting a reverse Wieringermeer effect (RWE) response type of groundwater. This rise was associated with a prompt change of pressure head values which exhibited instantaneous fluctuations of centimeters due to the addition of millimeters of water. The recharge volumes leading to such disproportionate water table rise were successfully estimated using a simple analytical model based on the moisture retention curve of the soil and considering the hysteresis effect on soil water dynamics within the capillary fringe zone.

We measured anisotropy of saturated hydraulic conductivity in clogged sand. Two sets of column ex... more We measured anisotropy of saturated hydraulic conductivity in clogged sand. Two sets of column experiments, 5x5x5 cm cubic column and 5x5x1 cm flat columns, were performed. We gave flow in two orthogonal directions to see if anisotropy of the flow is observed. We inserted three tensiometers into the sand column and observed their total head by using water manometers, and measured the effluent to calculate saturated hydraulic conductivity. We applied glucose solution of 50 g/m3 as a nutrient from top of the columns to create bioclogging (1st stage). Then we applied glucose solution from side of the columns by rotating the columns 90-degree and giving vertical flow to check both anisotropy and the difference of hydraulic conductivities between two directions (2nd stage). At last, we applied NaN3 solution as bactericide to clarify the effect of microbes on clogging (3rd stage). At the 1st stage, we applied nutrient from top of the sample for 10 days. The hydraulic conductivity of both ...

Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 1996

A series of column experiments were carried out to elucidate the effects of microorganisms on red... more A series of column experiments were carried out to elucidate the effects of microorganisms on reduction in the saturated hydraulic conductivity, Ks, of paddy field soil. The Ks of surface 1 cm layer decreased 2 orders of magnitude during 118 day period of percolation of 50 ppm glucose solution. After the alternation of percolation to germicide (NaN3), Ks increased rapidly. Population of bacteria near the surface did not increase, but that of fungi near the surface increased hundred times. Therefore it was proved that the first cause of Ks reduction is clogging of soil pores by hyphae of fungi and microbial synthesized products. The second cause of Ks reduction is occlusion of pore space by gas produced by anaerobic bacteria. The redox potential of all depths was below-150 mV at 15 day, which was sufficiently met for the CH4 production. From calculation of production and resolving rate, it was explained that all CO2 resolved in percolation, and that CH4 did not resolve perfectly. It ...

Journal of Hazardous Materials, 2009

The understanding of the gaseous adsorption process and the parameters of volatile organic compou... more The understanding of the gaseous adsorption process and the parameters of volatile organic compounds such as organic solvents or fuels onto soils is very important in the analysis of the transport or fate of these chemicals in soils. Batch adsorption experiments with six different treatments were conducted to determine the adsorption of isohexane, a gaseous aliphatic, onto volcanic ash soil (Tachikawa loam). The measured gas adsorption coefficient for samples of Tachikawa loam used in the first three treatments, Control, AD (aggregate destroyed), and AD-OMR (aggregate destroyed and organic matter removed), implied that the aggregate structure of volcanic ash soil as well as organic matter strongly enhanced gas adsorption under the dry condition, whereas under the wet condition, the aggregate structure played an important role in gas adsorption regardless of the insolubility of isohexane. In the gas adsorption experiments for the last three treatments, soils were sieved in different sizes of mesh and were separated into three different aggregate or particle size fractions (2.0-1.0 mm, 1.0-0.5 mm, and less than 0.5 mm). Tachikawa loam with a larger size fraction showed higher gas adsorption coefficient, suggesting the higher contributions of macroaggregates to isohexane gas adsorption under dry and wet conditions.

Geophysical Research Letters, 2005

Journal of Sustainable Watershed Science and Management, 2012

One of the important shallow water table's properties, especially for hydrologists and hydrogeolo... more One of the important shallow water table's properties, especially for hydrologists and hydrogeologists, is their interdependencies with overlying land and surface water. This topic was addressed by the XXV Congress of IAH, 1994. The theme of that meeting was "Management to Sustain Shallow Groundwater Systems". Selected papers from that congress were published in a book edited by Dillon and Simmers (1998). In the opening review paper "Shallow groundwater systems" of this 36

Rural and Environmental Engineering Ree, Feb 1, 2001

Soil Science, Jul 31, 1996

The bulk density of a soil changes with natural and artificial processes in a field. The larger t... more The bulk density of a soil changes with natural and artificial processes in a field. The larger the bulk density ρ b of the soil, the larger the air entry suction h e and the smaller the hydraulic conductivity K s . Although both the Kozeny-Carman equation, based on Poiseuille's law, and ...

Soil and Tillage Research, Dec 1, 2005

... Home page DJ Timlin, LR Ahuja, Ya. Pachepsky, RD Williams, D. Gimenez, and W. Rawls Use of Br... more ... Home page DJ Timlin, LR Ahuja, Ya. Pachepsky, RD Williams, D. Gimenez, and W. Rawls Use of Brooks-Corey Parameters to Improve Estimates of Saturated Conductivity from Effective Porosity Soil Sci. Soc. Am. J., September 1, 1999; 63(5): 1086 - 1092. [Abstract] [Full Text], ...