Rain infiltration under varying intensity of rain is studied based on the experiments undertaken.Two types of rain input were used in the experiments.The first type of rain input was of different intensities and of durations but had the same amount of rainfall.The second type of rain input was square-wave-type intensities with intermission of 0.5-1h.These inputs were given to the surface of the soil columns that were 2 m and 5 m in depth.Time-varying changes in the distribution of the soil-water content along the vertical axis of the model are observed by the normalized specific resistance of soil which was introduced in the former paper.
Observed phenomena in the experiments were:(1) A wetting front under the rain input of a smaller intensity and longer duration reaches deeper depth than that of the rain input of a stronger intensity and shorter duration under the condition that the same amount of rain water is given to the model.Soil-water content in the soil shallower than the wetting front decreased simultaneously after the rain stopped.(2) In the case of 2 m deep soil column, intensity of outflow from bottom corresponded to the change in the square-wave-type intensity of rain input.Intensity of outflow from the bottom increased after repetition of the square-wave input.
These phenomena are explained well by the Open-Unsaturated-Capillary-Percolation (OUCP) model which was introduced to explain the phenomena of infiltration observed under step-type of rain input in the former paper.

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Such ground hazards as landslide and slope failure often occur when intensity of rain increased after continuous rain on the ground.Slip surfaces of such hazards locate from surface area to below 5m deep zone.This shows that some triggering effects are caused at deep zone shortly after increase of intensity of rain.
In order to clarify these phenomena, infiltration under varying rain input was discussed based on experiments in the forme paper.In the present paper, phenomena caused by antecedent rain is studied based on experiments.Same rain input of 30mm/h for 2 hours was added daily for 5 days at the same time of the day to 5m deep column of loamy soil in the experiments.Apparent specific resistance of each depth of the column and groundwater outflow from bottom were measured.
Observed phenomena are:(1) Soil-water content in surface zone repeats wetting and drying responding to rain input, but primary wetting front moves downward continuously.(2) Secondary wetting front appears each time responding to rain input after the second day above primary wetting front.Secondary wetting front increases its downward velocity and reaches to deeper zone day by day when soil-water content increases.(3) Outflow of groundwater begins when primary wetting front reaches around top of capillary fringe, then local maximum intensity of outflow appears corresponded to the pattern of rain input.
Results discussed on these observations are:(1) Rain water of each day travels through capillary water zone above primary wetting front in a short period and primary wetting front moves downward continuously.(2) Capillary fringe grows high after primary wetting front reaches the fringe. Then outflow begins in a shorter period after rain and increases its intensity.(3) These phenomena caused by antecedent precipitation are explained by the Open-Unsaturated-Capillary-Percolation (OUCP) model.

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It is very important to estimate corrective pressure distribution to analyse uniformity of water application in microirrigation system.Finite element method is one of the very convenient and accurate methods to do this analysis.If the nodal system is arranged and simplified reasonably, personal computer can be used to calculate pressure distributioneven in a system with a large number of water application devices, such as line source emitterand high density point source emitters of trickle irrigation system.The accuracy of the solution is very high because theoretical calculating procedure is used.The convergence is quick no need to think whether the initial estimates of the nodal pressure are near or far from the final solution.

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The experimental study on setting time and compressive strength of concrete with normal portland cement and portland blast-furnace slag cement was performed under the condition of high temperature, 30-33°C.
The results are summarized as follows.
1) The setting time of the concrete with portland blast-furnace slag cement was far longer than that of concrete with normal portland cement.But, the content of blast-furnace slag in the cement, 45 % and 60 %, had relatively small effect upon the setting time of the concrete.The chemical admixture with retarder showed considerable effect on delay of the setting time of the concrete.
2) In case of the hot weather concreting, the rate of increase of long term strength of the concrete with portland blast-furnace slag cement was larger than that of concrete with normal portland cement.In case of the concrete with blast-furnace slag cement, the content of slag and the difference of chemical admixture had a little effect upon the compressive strength of the concrete, but the difference of chemical admixture had much effect upon that of the normal portland cement concrete.
3) Under the conditions of the high temperature and drying, the age of removal of forms had much more effect upon the compressive strength of the concrete than the content of blast-furnace slag in the cement and the difference of chemical admixture.

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A new numerical method, based on method of characteristics, combined with implicit and explicit time-line interpolations (MOC based-combined method) is proposed for reasonably analysing rapid and slow transients and steady flows in large scale pipelines.With the method proposed adequate time step sizes and optimal grids for computations are determined by considering numerical damping and dispersion due to time-line interpolations.When relatively short pipes exist, larger time step sizes are possible to use with implicit time-line interpolations.Numerical examinations reveal that MOC based-combined method is superior to rigid water column models in predicting pressure oscillations in slow transient analysis and easily dealing with valve closure problems.

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The Kushiro Higashi section of the wide area farm road is located in the nearly central part of the area of jurisdiction of Kushiro Branch Office in eastern Hokkaido.Of this, the first phase construction section passes through the Kushiro Marshland which is a weak ground.In the Hirosato Bridge area, sliding failure, residual sinking, the side flow of the abutments, the deformation of headrace culverts and so on were expected.As the countermeasures against them, it was decided to carry out the soil improvement, and for the backside of the abutments, the stabilizing methed of mixing in deep strata, and for the road part, the construction method of crushed stone compaction and piling were executed.
In this paper, the outline of these works is shown, and the designmethod, the procedure of execution, the method of execution management and so on of respective construction are reported.

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It can be said that the gravel in bed for tomato has simultaneous phenomena of evaporation and gravitational but very slow drainage. In this paper, the simple method could be developed for obtaining evaporation from gravel surface directly by means of weighing vessels of metal wire netting filled with gravel set in the gravel bed.
Then, it could be shown that the tomato transpiration per day might be estimated by water balance method introduced the simple method to tomato green house having exact information of evapotranspiration per day by means of water level measurement in the stock tank for culture solution. As the results, the ratio evaporation to transpiration in fine day could be estimated to 10%-20%.
Next, it was carried out that the comparison of tomato transpirations in green house obtained over a long period of time by a stem-flow instrumentation, that was progressed recently, and the water balance method.As the results, it could be found that the transpiration per day obtained by the former method was inclined to be higher than that by the latter method, and that the transpiration by the latter might have higher the correlation coefficientto the pan evaporation obtained at the center of the tomato furrow than to the sunshine time.The reason why the transpiration by the stem-flow instrumentation was inclined to be higher than that bythe water balance method could be due to the insolation intensity.
Mean transpiration of tomato obtained for the maturity of the growth could be estimated roughly to 0.7kg/day/plant.

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According to the questionnaire to land improvement districts and farmers in the ongoing and unexecuted land consolidation projects, farmers tackled projects for the sake of boosting agricultural productivity, grouping of farm land for core farmers and development of social infrastructure. On the other hand, some farmers are against the implementation of the projects because of the control of rice production, stagnation of government support for prices of agricultural product and restriction of agricultural land use.Core rice farmers in the future will be expected to be individual farmers using rental land, farmers associations with entrusted land, individual farmers involved in not only rice farming but also horticulture, livestock and so on, and farming groups at village level, who will request to be subsidized in order to accumulate more land.
With regard to the project scheme, 70 percent of the land improvement districts are affirmative in adopting the one person-one vote system included project implementation agreement.However, 10 percent, mainly in the Tohoku and Hokuriku districts, will consider farming scale system (large scale farmers'opinions should be reflected more compared to small scale farmers).Moreover, if qualified farmers, stipulated by Land Improvement Law, Article 3, would be all cultivators concerning rental lands, farmers in the western part of Japan will encounter difficulties.But one-third farmers mainly in the Tohoku and Hokuriku districts may have not such serious problems.

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Recent development of synthetic polymers that absorb and retain water is gaining popularity and attention in the agricultural fields especially in and and semi-arid regions.However, little is known of the release properties and availability to plants of polymer-stored water.
The objective of the current experiment is to study the moisture storage of four polymers and the influence of two Of them on the physical properties of soils of different textures in the laboratory. The polymers used were GH-2, CS-7 L, CN-1, and CS-6 L with swelling capacities of 200, 135, 170, and 200 times respectively.The GH-2 and CS-7 L polymers were treated with the various soil textures to determine the influence of the high water absorbing synthetic polymers (HWASP) on sandy soil, sandy loam soil and standard sandy soil.
A moisture characteristic curve of the 4 polymers revealed that the polymers released about 80 to 87% of the absorbed moisture at saturation (pF 0) until the soils'suction pressures reached pF 3.0.The slow?release of moisture could prove beneficial for water saving in areas where water is insufficient for agricultural use.Concerning the polymer-soil treatments, the water holding capacity of sandy soils 1, sandy soils 2, sandy loam 1 and standard sandy soils greatly improved with increase of polymer quantity, while no significant improvement was found in clay loam (Kuroboku) soil.Thus, the water holding ability is influenced by soil texture.Depending on the amount of polymer added, the moisture retention improved thereby improving the mechanical composition of soil. If pore spaces are adequate for polymer gels to re-arrange themselves, they can swell better thus, resulting in volume increase of entire soil.The moisture retention of sandy soil particle sizes in the range 2.00mm<d<8.00mm treated with 0.5% GH-2 polymer was higher than the other sandy soil particle size ranges.
There was an influence of electrical conductivity (EC) of the soil solution on the swelling capacity of the polymers.However, there was no apparent influence in the case of pH of soil solution. Hence, measurement of EC is a pre-requisite for polymer application.
The permeability of the soils treated with polymers was lower than the control since the polymer gels swelled to fill and sealed the pore spaces within the soils.

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The introduction of water absorbing synthetic polymers (HWASP) to improve the water holding capacity of soils is a significant new development to aid plant growth under moisture stress conditions.Most HWASP absorb water to several hundred times their own weight and act as slow-release water reservoirs when incorporated with the soil.
In this paper, the influence of high water absorbing synthetic polymers (HWASP) on soils with growing plants was investigated.The HWASP used were GH-2 and CS-7 L, which swell 200 and 135 times their weights in pure water respectively.Plastic vessels containing sandy soils, sandy loam soils and standard sandy soils were treated with the HWASP and ornamental plants were grown in each vessel in a glasshouse.
In this experiment, the moisture holding capacity of the soils improved remarkably and the improvement depended on the amount of HWASP mixed with the soils.Moisture improvement was more effective in coarse-textured soils than in fine-textured soils.
In general, when the quantity of polymer treated with the soils was increased the available moisture content also increased.It was shown that the period of time taken by the soil suction to reach pF 2.8 (irrigation interval) was lengthened resulting in saving irrigation labor time.
After 18 months of planting it was observed that the GH-2 and CS-7 L polymers are still effective and have not undergone degradation yet.Mixing the polymers directly with the soils was found to be better in improving the water holding capacity than when separated in bags.Also it was seen that the available moisture released by the CS-7 L polymer was higher than the GH-2 suggesting that the high rate of water absorption of individual polymers in pure water is not a major criteria for selecting polymers for use in agriculture.

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