• The Korean Journal of Ecology
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• v.20 no.5
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• pp.375-384
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• 1997

The effects of three different irrigating water qualities(clean water, life sewage and animal sewage) on the pattern of arthropod communities in the rice fields were investigated at Banwol, Kyonggi-do, mid-western part of Korea from 1994 to 1996. The total density of arthropod was highest in the rice field which was irrigated with clean water(clean water field), and the arthropod community was mainly composed of aphids and collembolans. Each functional group was found in the order of 'pests>non-pests>natural enemies' in its density. The dominant taxa in the pest group were aphids, planthoppers(Delphacidae), leafhoppers(Cicadelidae) and rice water weevil(L. oryzophilus). In the non-pest group collembolans, non-biting midges and dipterans were main arthropods, and in the natural enemy group Araneae was the dominant taxon. In the early growth stage of rice plant the dominant functional group was pests, and in the mid growth stage both the pest and the natural enemy group became dominant. But in the late growth stage none of the functional group was dominant over the other functional groups. The densities of spiders were much more higher in the clean water field than in the other fields. And through all the growth stages of rice plants the density of spiders in clean water field kept increase in contrast to the others. The species composition of spiders in the life sewage field was similar to that in the animal sewage field, but in the clean water field it was different from the other two fields.

• Journal of Soil and Groundwater Environment
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• v.20 no.7
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• pp.34-42
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• 2015

Feasibility tests for the hydraulic fracturing were conducted in order to secure additional saline groundwater for irrigating to the land-based aquaculture farm. Two boreholes were placed to the aquaculture farm A and B, respectively. A hydraulic fracturing using single packer was applied to major fracture zones within two boreholes. To identify effects of hydraulic fracturing on securing additional saline groundwater, some selective methods including well logging methods, pumping tests, and groundwater quality analysis were commonly applied to the boreholes before and after the hydraulic fracturing. Enlarging/creating fracture zones, increasing water contents in bedrock near boreholes, and increasing transmissivity were observed after the hydraulic fracturing. Even though the hydraulic fracturing could be an alternative to secure additional saline groundwater to the land-based aquaculture farm, salinity of the groundwater did not meet optimal thresholds for each fingerling in two farms: Fresh submarine groundwater discharge flowed the more into borehole of the farm A that resulted in decreasing a salinity value. Increased saline groundwater quantity in the borehole of the farm B rarely affect to the salinity. Although salinity problem of groundwater limited its direct use for the farms, the mixing with seawater could be effectively used for the fingerlings during the early stage. A horizontal radial collector well placed in the alluvial layer could be an alternative for the farms as well.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.1
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• pp.1549-1560
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• 1969

When this experiment was treated with various factors of times and vacant intervals of intermittent irrigation in order to search for the effect on the growth of rice-plant and ti's amount of havestr, the following results were obtained during the period of this study. 1. Temperature was high, precipitution during nuturitive growing period, was suitable and Much rainfull, scanty sunlight during reproductive growing period and especially during decrease-sementation period, the cultivative situation of rice-plant of 1968 was almost similar to that of mean year. 2. It was found out that the quality of irrigated water used in the experioment was due to ti's neutural acidity. 3. The soil used in each experimental section was good for fertiligation and similar to the quality of general soil according to the result of soil analysis. 4. It was generally found out that the earlier times of intermittent irrigating and the longer vacant intervals of intermittent irrigation, the worse the growing condition of segmentation period was. 5. When vacant intervals of suspension of water supply were longer, the begining of being in ear of rice-plant ant the time tended to be late about one day. 6. In the view of the growth of maturity period and the amount of intermittent irrigation, it tended to be that the length of stalk of rice-plant was short when time of intermittent irrigation began earlier and the length of ear which came from any various section was not different. When times intermittent of irrigation began gradually early, the number of ears, grains and the weight of grains tended to decrease depending on times of that. All the growing of rice-plant and the amount of havesty tended to decrease, depending on which vacant intervals of intermittent irrigation were long. Finally, it was founedt out that from the point of view of the statistical analysis of weight of grains, it was more then 1% what highly significance of mutual action between times and vacant intermittent irrigation was researched.