• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.2
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• pp.45-52
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• 2016

The object of this paper was to evaulate modified proposed design equation in model test result in order to estimate uplift-resistance of timber pile of reclaimed land greenhouse foundation. Uplift resistance result of model test was increased to according to increased of contact area. Uplift-resistance result of field test tend to lineary increased to according to increased of embedment depth and contact area. Results of field uplift-resistance was evaluate compare with modified proposed design equation results of model test and Effective stress method. As the Effective stress method tend to underestimate, modified proposed design equation results of model test tend to similar type. As the contact area increase, difference between field uplift-resistance results and modified proposed design equation results of model test was considered uplift-speed.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1222-1229
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• 2012

The total area of a reclaimed tidal soil distributed on the south-west coast is approximately 156,600 ha, and the soil contains high contents of sand and silt as well as highly saline. Most of the reclaimed tidal soils are used as a paddy due to bad permeability and high groundwater table, resulting in easy accumulation of salts on the soil surface by capillary rise. Therefore, resalinization may occur because of rise of groundwater table after desalinization. The researches related to the reclaimed tidal soil mainly focused on desalinazation while most of the researches completed were limited to yields of crop based on desalinazation. pH of old reclaimed tidal soil is neutral or less than 7 while that of newly developed reclaimed tidal soils is greater than 7, that cause N-fertilizer to be volatile as ammonia. Thus, the physical and chemical properties should be investigated to be used as an arable upland instead of a paddy soil due to change in government policy. We need to develop measures to make soils grow crops normally by identifying problems related to reclaimed tidal soils.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.418-424
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• 2014

The Agricultural Land Remodeling Project was launched for agricultural fields with potential risk of flooding which were placed in low-lying area as a part of agricultural sectors of the National 4 River Project. It induced of the reclaimed agricultural fields on a national scale. The arable lands reestablished by reclamation have caused several big problems such as destruction of soil physicochemical properties, and thus the techniques to solve disadvantages were urgently required. In this study, we collected experimental samples from top soils in three agricultural areas, one from conventional agricultural fields (Hwasun, Jeollanam-do) and the others from reclaimed (remodelled) agricultural fields (Naju, Jeollanam-do and Gumi, Gyeongsangbuk-do), The soil chemistry data were analyzed using statistic tools such as semi-variance and kriging, and differences between natural and reconstructed soils were examined. The score, R (Ao) which indicates a dependence distance between each chemical element, was as follows; 21.8~43.5 (Conventional, Hwasoon), 4.4~70.6 (Remodelled, Naju) and 5.3~43.6 (Remodelled, Gumi). These results suggested that chemical properties of the reclaimed agricultural fields had a huge variation. Moreover, the result of kiriging maps also represented a ununiform pattern in the reclaimed lands. As a result of this study, it is strongly required to build up the soil type-specific management techniques for the reclaimed agricultural lands.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.269-280
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• 2014

To cope with increasing of vegetables and flowers consumptions, horticulture facilities have been modernized. Korea government recently announced construction plan of new greenhouse complex at reclaimed land. However wind characteristics of reclaimed land is totally different from those of inland, wind pressure on greenhouse built in reclaimed land should be carefully evaluated to secure structural safety on the greenhouse. In this study, as a first step, wind pressure coefficient and local wind pressure coefficient on even-span greenhouse were measured using wind tunnel test. ESDU was adopted to realize wind characteristics of reclaimed land such as wind and turbulence profiles. From the wind tunnel test, when wind direction was 0 degree, it was concluded that KBC2009 standard underestimated scale of wind pressure coefficients at roof area of greenhouse whereas NEN-EN2002 standard underestimated those at every surface of greenhouse. When wind direction was 90 degree, both standards did not well reflect the characteristics of wind pressure distribution. From the analysis of local wind pressure coefficients according to wind direction conditions, design of covering, glazing bar of greenhouse where large effects of the local wind pressure were estimated should be well established. Wind pressure coefficients and local wind pressure coefficients according to parts of the greenhouse were finally suggested and these results could be practically used for suggesting new design standards of greenhouse.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.391-400
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• 2014

The number of large scale greenhouses has recently been increasing to cope with mass consumption of agricultural product. Korean government announced a new development plan for constructing greenhouse complex in reclaimed lands for the purpose of improvement in exports and activation of domestic market of agricultural product. Wind environment in the reclaimed land is totally different from that of inland area, and it can give a strong influence on ventilation performance of naturally ventilated greenhouse facilities. In this study, internal airflow analysis of naturally ventilated greenhouse built on a reclaimed land was conducted using wind tunnel and PIV for validation research. Later, the PIV measured results will be used to improve the accuracy of 3 dimensional CFD simulation in the future. Wind profile at a reclaimed land was produced using ESDU program and it was applied to the wind tunnel. The calculated error was only 5% and 0.96 of correlation coefficient, implying that the computed profiles were designed properly. From the measured results, when external wind speed changed from $1m{\cdot}s^{-1}$ to $1.5m{\cdot}s^{-1}$, air velocities inside the greenhouse which PIV measured were also increased proportionately in case of both side vent open and side-roof vent open. Considering reduced ratio of air velocity inside the greenhouse, it was measured a minimum of 40% in case of side vent and 30% in case of side-roof vent compared with external wind speed from each vent type. From the quantitative and qualitative PIV analysis, the PIV measured results indicated that there were well ventilated and stagnant areas in the greenhouse according to external wind condition as well as ventilation design.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.2
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• pp.129-135
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• 2013

This study was conducted to investigate the soil characteristics of newly reclaimed tidal land and the effect of green manure crops on soil properties. Summer green manure crops such as sesbania (Sesbania grandiflora), barnyard grass (Echinochloa spp.) and sorghum${\times}$sudangrass hybrid (Sorghum bicolor L.) were cultivated at Hwaong, Ewon, Saemangeum and Yongsangang area. Soil pH of reclaimed tidal land was relatively high, but organic matter and available phosphorus contents were lower compared to the optimum range for common upland crops. Soil nutrient contents were unbalanced for upland crop growth. Yield of green manure crops had a wide spatial variation. Nitrogen content in green manure crops was the greater in Sesbania and it was estimated that major nutrient ($N-P_2O_5-K_2O$) supply amount were 150-40-370, 220-50-170 and 140-50-250 $kg\;ha^{-1}$ from sorghum${\times}$sudangrass hybrid, sesbania and barnyard grass, respectively. Based on these results, desalination is required to grow the upland crops at newly reclaimed tidal lands and management practices are necessary to reduce the salt damage by resalinization during the growing seasons. To improve the productivity and increase the nutrient utilization rate, soil physicochemical properties need to be improved to the level for upland crops by application of organic matter and fertilizer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.413-421
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• 2023

Data on salt tolerance, optimal sowing depth, soil bulk density (pb) and cardinal temperatures required for the germination and emergence of perilla (Perilla frutescens (L.) Britt) are scarce for reclaimed land soil. An experiment was conducted across six temperature treatments (10, 15, 20 , 25, 30, and 35℃) to determine the cardinal temperature for perilla seed germination and four salinity levels (0, 20, 40, and 60 mM) to determine the salt tolerance. Another experiment was performed for quantifying the emergence response of perilla to pb (1.1, 1.3, and 1.5 g cm^-3), sowing depth (1, 2, 3, and 4 cm) and soil salinity. The results revealed that increased sodium chloride levels caused a significant reduction in the seed germination at Deulhyang and Sodam. The optimum upper limit temperature was less than 35℃. The optimal sowing depth and soil bulk density were 1 cm and 1.1 g cm^-3 respectively. Perilla seedling growth was inhibited at 1.9 dS m^-1 although varying responses were observed. These results aid our understanding of the germination and emergence rate of these crops and provide data for field cultivation to optimize crop sowing in reclaimed land.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.739-746
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• 1999

Discharge characteristics of organic materials and nutrients were estimated in the catchment area of relaimed area-Saemankeum-. Discharge load of BOD5 was high in the domestic system, while nitrogen and phosphorous were discharged mainly from the livestock system and the land . Load was so dependent on the precipitation that it increased in the rainy season, particulary in nitrogen and phosphorus. Loads from nonpoint sources in this area were higher compared with others.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.46-50
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• 2005

This study was carried out to investigate the proper nitrogen fertilizer level at reclaimed saline land in the southwestern area of Korea from 2002 to 2004. The rice cultivars tested were Samcheonbyeo(Early maturing one), Nampyeongbyeo (Medium maturing one) and Hwaseongbyeo(Mid-late maturing one). The results aye summarized as follows: The more the nitrogen level, the more number of panicle and spikelet per unit area was. But, ripened grain rate and 1000-grain weight were decreased at higher nitrogen level. As higher nitrogen level, head rice rate was decreased and protein content was increased. But, amylose content wasn't differ among the nitrogen fertilizer application levels. As increase nitrogen level in head rice yield increased up to 12 kg/10a, 11 kg/10a, in Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo, respectively. But there wasn't different more than it. Consequently, considering the yield of head rice, ripened grain rate and rice quality. The proper nitrogen fertilizer application level was 11-12 kg/10a at reclaimed saline land in the southwestern area of Korea.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.185-192
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• 2000

Recently, the hydraulic fill method is commonly used in many reclamation projects due to lack of fill materials. The method of hydraulic fill in reclamation is executed by transporting the mixture of water-soil particles into a reclaimed land through dredging pipes, then the dredged soil particles settle down in the water or flow over an out flow weir with the water. In the present study, practice each three method in order to suggest method of determining the loss rate of the dredged fills. The first sieve and hydrometer analysis were performed with the soil samples obtained before and after dredging and then apply theory of particle breakage, the second compare with the volume of dredged soil between at the dredging area and the target pond and the last compare with weight of dredged soil between before and after dredging at the dredging area and in the target pond for estimating the amount of soil particles residual at the reclaimed area and the loss of soil particles passed through the weir. In addition to compare with the loss ratio between as using Marsal's modified theory of particle breakage and measured weight and volume in the field.