| Budget Amount *help |
¥7,400,000 (Direct Cost: ¥7,400,000)
Fiscal Year 1985: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1984: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1983: ¥3,900,000 (Direct Cost: ¥3,900,000)
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| Research Abstract |
The water requirement in paddy fields has become varied and complex these days. This research was performed for the effective water management of irrigation and drainage of paddy fields in Tohoku and Hokkaido district. The results of the three given subjects are as follows.
1. Effective Managemant of the Facilities for Water Supply in the Situation of Declining Acreage Farmed.
(1) According to opinionaire, rice transplanting is finished in more than 80% of the total paddy fields at the last day of the period of puddling water. Water level in the period of deep ponding irrigation is much lower than expected.
(2) The open canal shoud be used more effectively, to shorten the time required for irrigation in both the puddling water and deep ponding irrigation periods and to change the continuous flow irrigation to the intermittent one at the other times.
(3) Based on the ideal water temperature of paddy field, the open canal and water warming pond, we calculated the water temperature of both co
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ntinuous and intermittent flow irrigation at each time of the day. We indicated the advantage of the intermittent flow irrigation and indicated the ideal duration and the starting time of intermittent flow irrigation.
2. Utilizing Structure and Effective Use of Cool Water Irrigation in Paddy Fields Area. In order to clarify the change of water utilization caused by the farm land consolidation, a questionnaire was carried out on the three mountain villages of North Tohoku district, in which the paddy fields had been suffering every year from damage caused by cool water temperature.
As a result of investigating many data, it was shown that the water utilization on paddy fields was improved from a flowing irrigation to a intermittent irrigation, therefore cool summer damage and cool water damage in this paddy field land decreased remarkably for the reason of water temperature rise in paddy field.
3. Effects on Internal Drainage of the Existing Drainage Network with the Conversion from Paddy Field to Upland Field
The internal disasters are examined and the precipitation is estimated, based on hydrological statistics, and the ponding analysis of runoff is calculated during the strm rainfall in August, 1975 and 1981, especially in Kitamura and Yubaributo regions. Less
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