• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.69-75
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• 2013

Miscanthus has received wide attention as an option for biomass production in Korea, recently. New strain of giant miscanthus has been developed and was planted in two large trial sites (184 ha) in the lower reaches of the Geum River. To evaluate the susceptibility of the giant miscanthus as an bioenergy crop for the future, we investigated the influence of the giant miscanthus on the soil properties. The particle size, CEC, pH, EC, T-N, T-P, heavy metal total concentration, and heavy metal fractions of soil samples collected from abandoned field, 1 year old giant miscanthus field (1st Year GM), and 2 year old giant miscanthus field (2nd Year GM) at different depths of 0~15, 15~30, and 30~45 cm in April and August were analyzed. Results showed that the CEC and pH of the soil of the giant miscanthus field were lower than those of the soil of abandoned field. The EC of 2nd GM was lower than that of abandoned field, indicating that the giant miscanthus may facilitate soil desalination process. The organic and sulfide fraction and residual fraction of heavy metals in the giant miscanthus field was higher than in abandoned field, due to the low pH of the giant miscanthus field and the excretion of phytosiderophores by rhizome of the giant miscanthus. This study showed that the giant miscanthus can influence on the soil properties and further study for long term is needed to elucidate the interaction between the soil and the giant miscanthus.

• 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.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.5
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• pp.60-71
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• 2008

Through analyzing the specific physicochemical alterations in depth-based soil at reclaimed dredging area, the baseline data were provided for developing the reclaimed dredging area as natural landscape planting sites and ecological-landscape sites based on the soil improvement technology. There was no physical disturbance for 15 to 20 years in Gwangyang Bay reclaimed dredging area after reclamation. Physicochemical examinations of the soil were performed based on the vertical depth. Results of physicochemical analysis such as pH, electric conductivity, total salt contents, silt, clay contents, available phosphorus, calcium, magnesium, sodium, chlorine, and sodium-adsorption ratio showed increasing patterns with the depth while total organic contents, total nitrogen, and sand showed decreasing patterns. Potassium as an exchangeable cation, showed similar distribution patterns between the shallow and deep soil. This result strongly implied that long-term exposure to natural rainfall in reclaimed dredging area altered soil characteristics related to salinity. This research demonstrated that there were no remarkable differences in physicochemical characteristics at soil depth and groundwater table height, suggesting a baseline data for developing reclaimed dredging area. Additional investigation is required for different reclaimed dredging areas. Also, additional monitoring and examination are need on plant communities and time variable alteration in the soil to test the feasibility of reclaimed dredging areas as natural landscape planting sites and ecological-landscape sites.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.115-121
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• 2009

In order to elucidate the mechanisms affecting plant distributions in the reclaimed dredging area in the Gwangyang steelworks, in the Gwangyang Bay, Korea, we examined soil characteristics and plant distributions in four study sites and a control site in the study area. Desalination occurring along a gradient with increasing elevation, resulting in decrease of soil pH, EC, P, K, Cl, Ca, Mg, and salt and an increase in soil T-N, silt, clay contents. From site 1 (the lowest-elevation site) to site 5 (the highest-elevation site), halophytes decreased in abundance and nonhalophytes increased. The dominant species in each site were: Phragmites communis, Limonium tetragonum, and 12 additional species at site 1, Carex pumila, Suaeda japonica, and 15 additional species at site 2, Spergularia marina, Scirpus planiculmis, and 22 additional species at site 3, Miscantus sinensis, Lespedeza bicolor, and 26 additional species at site 4 and Pinus thunberii, Rhododendron mucronulatum, and 39 additional species at site 5, which resembled a naturally-occurring P. thinbergii community. Cluster analysis of the vegetation data matrix grouped the 35 plots into 5 major groups, and cluster analysis using the soil environment data matrix revealed 4 major groups. CCA of the floristic and environmental data matrix showed a positive relationship of SAR, EC, Na, Cl, and Ca, which are related to salt, in the $1^{st}$ axis and $2^{nd}$ axis, but negative relationships for altitude, organic contents, silt, and clay contents. Notably, plant species in the reclaimed dredging area that were separated along the $1^{st}$ axis showed strong relationships with factors that related to salt. Long-term exposure to natural rainfall in the reclaimed dredging area changed the soil characteristics, such as salinity. This change in soil characteristics might alter the SAR, which affects plant survival strategies in a given habitat. These results strongly indicated that factors related to salt and elevation play important roles in determining the overall plant distribution in the reclaimed dredging area.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.1
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• pp.55-60
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• 1988

A two year's field experiment was conducted on newly reclaimed saline tidal lands to measure the effects of sand mulching on salinity of the soils and their relationship to crop performance. Hybrid sorghum cv. Pioneer 931 was grown under different mulching treatments using of medium sand and red earth (Fine loamy, Typic Hapludults). Salinity in the root zone was decreased markedly under soil mulching using of medium sand, especially during the dry season, and it caused a great increase in the root growth and R/T ratio. Seasonal values of electrical conductivity at sand mulching were 6.6 in April and 1.6 mmhos in August, but it was still high with a concentration of 12.7 (April) and 3.8 mmhos (August) in untreated check plot. Sand mulching increased plant growth and the rate of dry matter accumulation. However, treatment of red earth additionally over sand mulching produced lower dry matter yield than those of soil mulching using of medium sand only. Under salt stress sorghum plant showed a decrease in the leaf weight ratio (LWR) and it resulted in a low concentration of crude protein of the plant. Sand mulching enhanced leaf weight ratio and rate of protein synthesis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.2
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• pp.136-141
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• 2013

This study was conducted to investigate upland crop at reclaimed sand land 'Saemangeum' for early desalination purpose and to investigate the growth and yield of whole crop barley, which was acceded after summer crop of corn and rice. Seedling establishment of whole crop barley were 216 seedlings/$m^2$(25%) for non-flooding, 43% for 1 month and 58% for 2, 3 month flooding. And it was 60% in rice cultivation. Soil salt concentration was 0.5% in non-flooding treatment, however flooding treatments decreased to 0.2% or less. In general soil salt concentration increased until the middle stage of growing, then became to similar level as the seeding time. Plant height, stem length and number of tiller were increased with flooding treatment. Whole crop barley yield was significantly reduced in non-flooding treatment but rapidly increased by flooding treatment. Yielding at 3 months increased by 504% compared to non-flooding, and rice cultivation was also increased by 536%. Protein and fiber content was low in 1 month flooding treatment, 3 months flooding and rice cultivation showed the similar results in terms of feed value. For desalination purpose in reclaimed land, 3 months flooding treatments of rice cultivation could result in higher yielding for upland crop, such as whole crop barley.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.61-67
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• 1997

This experiment was carried out from 1979 till 1983 to elucidate the underdrainage effect on soil salinity and growth of rice plastic underdrainage was established 5m and 8m intervals in April of 1979 and Jinjubyeo the medium maturing rice variety was transplanted by hand at late of May. The results are as follow; The desalination effect was higher in 5m interval underdrainage than 8m interval underdrainage and the salt content was lower than 0.3％ at 1 year after in 5m interval, 2 years after in 8m interval underdrainage and 3 years after at control. Farther the distance from underdrainage position, less the desalinization rate that desalinization was least at center part of the underdrainage position. Desalinization effect was highest 30cm of soil depth and decreased deeper than it. Shorter the underdrainage interval, more the panicle number, heavier 1, 000 grain weight and higher the milled rice yield. But the milled rice yield wasn't significantly different between the underdrainage interval from 3 years after underdrainage.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.197-206
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• 2018

BACKGROUND: The present study aimed to examine the crops capable of growing and adapting to the external environment and various stresses of reclaimed agriculture land for the development of high value-added agricultural utilization technology based on reclaimed land through standardization and empirical study of cultivation environment for cultivating crops. METHODS AND RESULTS: Two crops namely turnips and beets were selected for the salt tolerance test of soil environmental conditions on reclaimed land. Turnip and beet seedlings were planted on the soil collected at the 'Seokmun' reclaimed land. There are five treatments such as non-treatment, 1.0, 2.0 (control), 4.0 and $8.0dS{\cdot}m^{-1}$ of EC. The contents of betacyanin in beet roots was highest in control and decreased with increasing salt concentration. The GSL contents in the turnip roots waswere highest at EC 2.0 and decreased with increasing salt concentration, whereas those in turnip leaves waswere high both in the non-treated control and atthe EC 1.0-treatment. But, tThere was, however, no statistical differences among the treatments. CONCLUSION: The degree of salt tolerance of crops was examined, and the limit EC iswas expected to be $3.0{\sim}4.0dS{\cdot}m^{-1}$ as reported to date. If the soil improvement is performed and irrigation systems are used in the actual reclaimed land, the EC of supplied irrigation will be low, and desalination effecttreatment by the lower EC of the supplied irrigation on the soil will lead to more favorable soil condition of the rhizosphere and cultivation environment offor the crops than those in the port experiment. Therefore, monitoring the salinity, water content and ground water level will enable prediction of the rhizosphere environment, and setting up irrigation management and supplying irrigation will lead to crop cultivation results that are close to normal.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.1-13
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• 2018

The grain complex of Saemangeum is created for promoting the foundation of agriculture combined the global competitiveness. However, the masterplan is being also revised with changing of local conditions and social needs. Thus, the dynamic masterplan is needed to consider the change of time for Saemangeum project. The present study was made to set up the dynamic masterplan of Saemangeum grain complex for handling the change such as project progress, local environment, and project conditions flexibly. In this study, the dynamic masterplan for the progressive development of water supply, farmland composition, and introduction facilities is presented to the 6-2 zone in three stages. We believed that the water supply would be possible through the pumping and desalination facilities with the development stages. The farmland composition proceeded for each complex with reclamation, soil preparation, and soft soil processing. And it is planned to carry out crop cultivation from the complex where the construction is completed first. The introduction facilities were analyzed focusing on the silos and forage loading facilities, and the optimal location of them was selected using road and accessibility. The concept of dynamic masterplan may provide the direction for the planning and progress of reclamation project.

• Journal of Soil and Groundwater Environment
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• v.28 no.3
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• pp.12-28
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• 2023

Each national groundwater monitoring well showed distinct change patterns in groundwater levels and electrical conductivity (EC) in the Nakdong River Estuary, implying different external forces (EFs) on each well. According to the annual average data in 1997-2020, seawater was invaded into Well C. The desalination rate of -1,062 µS/cm/year represents the adaptive capacity of the well to seawater intrusion. The water levels and EC in Well E responded to precipitation, indicating the low absorptive capacity to climate changes. Meanwhile, Well B showed constant increases in water levels, suggesting that problems by rising groundwater should be considered in the study area where confined aquifers are overlaid by clay aquitards. The other wells showed consistent water levels and EC, indicating resilience to EFs. Here, resilience is the capacity of a well to resist changes by EFs, including the absorptive and adaptive capacity. The resilience of Wells E and F to climate changes was quantitatively compared using a resilience cost (RC). The RC showed Well F was more resilient than Well E, and the bedrock aquifer was more resilient than the alluvium aquifer, supporting the usefulness of RC. The resilience assessment against EFs (e.g., changes in land use and climate) helps sustainable groundwater management.