• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.447-453
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• 2009

Vegetation distribution and soil salinity were surveyed on the conservation plot in the Daeho reclaimed tidal land, in where the plants species distribution was more various than a periodically inundated tidal flat and the early stage of reclamation. According to the soil salinity where the vegetation patches were occurred, the mono patches of Salicornia europaea, Suaeda maritima, and Suaeda glauca were distributed in the average range of 31.05 dS/m in soil salinity, the mixed patches of them were distributed in the average range of 42.75 dS/m. Therefore, Salicornia europaea, Suaeda maritima, and Suaeda glauca showed strong salt tolerance. The mono patches of Aster tripolium, Sonchus brachyotus, and Scirpus planiculm were distributed in the range of 11.73 dS/m in soil salinity, and the mixed patches were distributed in the average range of 9.43 dS/m. Therefore Aster tripolium, Sonchus brachyotus, and Scirpus planiculmis showed moderate salt tolerance. The mono patches of Imperata cylindrica, Trifolium pratense, Miscanthus sinensis, Setaria viridis, and Trisetum bifidum were distributed in the range of 2.42 dS/m in soil salinity. These species showed characteristics of glycophytes with weak salt tolerance. The distribution of vegetation patches was influenced by the soil salinity as pioneer halophytes patches occurred at higher soil salinity zone than facultative halophytes patches, glycophytes patches occurred at lower soil salinity zone than facultative halophytes. These results suggested that occurrence of plant species and plant distribution type might be useful index to evaluate the soil salinity and desalinization in the reclaimed land of the midwest coastal area of Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.529-539
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• 2010

In order to evaluate the effect of soil salinity and culturing conditions including compost application and vinyl mulching on the maintenance of ridge and the growth of upland crops, three crops such as corn, soybean and sweet potato were experimented by using three or four cultivars of crops in the Saemangeum reclaimed tidal land. Average soil salinity before seeding was 2 dS $m^{-1}$, which was low enough for general upland crops to grow. However, high soil EC more than 16 dS $m^{-1}$ was observed in some parts of the experimented field. In the experiment, it was concluded that growth retardation and yield reduction of summer upland crops might be from severe erosion of ridge, soil compaction, flooding or wet soil condition and high salinity of some parts, and then these deteriorations were possibly improved for good crop growth and yield increase by compost application and vinyl mulching cultivation in the Saemangeum reclaimed tidal land.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.84-90
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• 2011

It is imperative to study the hydrolysis of urea in high saline-sodic condition of a newly reclaimed tidal land in order to overcome the problems associated with use of urea fertilizer. The methodology adopted in this study tried to get a convenient way of estimating rate for N transformation needed in N fate and transport studies by reviewing pH and salt contents which can affect the microbial activity which is closely related to the rate of urea hydrolysis. The hydrolysis of urea over time follows first-order kinetics and soil urease activity in reclaimed soils will be represented by Michaelis-Menten-type kinetics. However, high pH and less microorganisms may delay the hydrolysis of urea due to decrease in urease activity with increasing pH. Therefore, the rate of urea hydrolysis should adopt $V_{max}$ referring enzyme activity ($E_0$) accounting for urease concentration which is indicative for urea hydrolysis, especially in a high saline and sodic soils.

• The Microorganisms and Industry
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• v.19 no.2
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• pp.49-57
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• 1993

Chenges in respiration of the soils collected from the reclaimed tidal soil in Chogi-ri, Kanghwa Island and treated with organic matters are presented. The measurement of the respiration for the smaples, which were incubated for 0,2,4 and 5 weeks, were carried out by using Warburg's respirometer. While the respirations of the samples added by organic matters were increased 6.7 - 28.0 times compared with that 0 week during the incubation in case of 5-year soil, the respiration in case of 3-year soil were increased 3.3-11.8 times. Thus, the effect of adding organic matters on the respiration of the experimented soils, as this indicates, was much higher for the soil of 5-year area than that of 30-year area. And for the organic matters Salicornia was most effective and then Suaeda and Oryzae. The samples treated with Salicornia and Suaeda showed their highest respiration rate at the 4th week, but the one with Oryzae was measured to increase progressively during 5 weeks experimented. Regarding the salinity, content of organic matters and number of bacteria, in each intact soil experimented, 5-year soil samples had much poor habitat then 30-year soil for the activity of soil microorganisms, but according to the result mentioned above, it is firmly believed that the addition of organic matters on the saline soil is one of the best means to change the reclaimed tidal land into arable land with less time duration.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.29-37
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• 2011

The experiment was carried out to find the effects of transplanting time and vinyl-film mulching treatment on the growth of artemisia by randomized block design with three replications. The experiment site ($100{\times}130$ m) was temporally established in the south-eastern part of Saemangeum reclaimed tidal land (near Gwanghwal myun, Gimjae-gun, Jellabukdo). Artemisia plants had been partly suffered from salt injury, because soil salinities in some area during growing period had been measured higher than 10 dS $m^{-1}$. Growth of plant height and survival ratio of transplanted plants had been significantly correlated with soil salinity and then the regression equations between plant height (y) and soil EC (x) and between survival ratio (y) and soil EC (x) were expressed as y=-16.59ln(x)+43.852 and $y=0.6453x^2-17.566x+103.99$, respectively. It was concluded that early transplanting and vinyl mulching was more beneficial for biomass production of artemisia, because biomass was 6.41 times more in the early transplanting than in the late transplanting, and 2.63 times more in the vinyl-film mulching than in the no mulching treatment.

• The Korean Journal of Ecology
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• v.20 no.4
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• pp.275-283
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• 1997

Vertical and temporal characteristics of desalinized reclaimed soil were analyzed from reclaimed coastal land on the western coast of Korea. Of the vertical changes during desalting, pH valuse were the lowest at the topsoil without regard to reclaimation time. The content of C1 were designated as the early period (the first 2-4 years) which decreased exponentially and the later period(the last 5-7 years) which was almost constant, from top to down. In temporal changes of the soil attributes, pH values increased for 5 years and decreased at 6 year after reclamation. Chlorine leaches more rapidly than Na does, K and Ca are constant but Mg increases as time elapsed after reclamation. Sometimes the content of Ca and K in the reclaimed soil are of higher concentration than that of the seawater after reclamation. During desallinization as exemplified by decreasing EC of the soil, Cl and Na are rapidly leached, but K, Ca and Mg are somewhat enhanced. The ration of Na/Cl in the soil equals 1 when the EC registers 5 mmho and then increases dramatically as the EC decreases. Rapid leaching of $Cl^{-}$ elicits an increasing pH valus. The electrostatic balance of the soil is achived by replacement of $Cl^{-}$ with $OH^{-}$ until stationary or until a decreasing pH value is reached again.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.283-290
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• 2023

The Republic of Korea reclaimed land to increase its food self-sufficiency rate, but the yield was reduced due to abnormal climate. In this study, it was hypothesized that rapid and continuous monitoring technology could help improve yield. Using the vegetation index (VI) analysis, the drought stress index was calculated and the drought stress for corn grown in Hwaong, Saemangeum, and Yeongsan River reclaimed tidal land was predicted according to drying treatment. The vegetation index of corn did not decrease during the last 20 days of irrigation when soil moisture rapidly decreased, but decreased rapidly during the 20 days after irrigation. The reduction rate of the vegetation index according to the drying treatment was in the order of Saemangeum>Yeongsan River>Hwaong reclaimed tidal land, and normalized difference vegetation index(NDVI) decreased by approximately 50% in all reclaimed tidal lands, confirming that drought stress occurred due to the decrease in moisture content of the leaves. In addition, structure pigment chlorophyll index (SIPI) and photochemical reflectance index (PRI), which are calculated based on changes in light use efficiency and carotenoids, were reduced; drought stress caused a decrease in light use efficiency and an increase in carotenoid content. Therefore, vegetation index analysis was confirmed to be effective in evaluating and predicting drought stress in corn growing on reclaimed tidal land corn.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.1
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• pp.31-39
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• 2017

The effects of application of gypsum and fresh cattle manure on the yield of forage crop were investigated in Hwaong reclaimed land in Korea for 3 years from 2011 to 2013. This study was conducted to develop the practical application method of livestock manure as a fertilization source and a soil physico-chemical ameliorator for the cultivation of forage crop $Sorghum{\times}Sudangrass$ hybrid in newly reclaimed tidal land soil. Treatments with six applications were established with three replications; chemical fertilizer (CF), gypsum (G) $20Mg\;ha^{-1}$, G+fresh cattle manure (FCM) 100%, G+FCM 200%, G+FCM 300% and FCM 100% which referred to the application rate equivalent to the recommended amount of phosphate fertilization by soil test. The combined treatments of G+FCM increased soil organic matter, $Av.P_2O_5$ and exchangeable $Ca^{2+}$ contents while decreased exchangeable $Na^+$ and $Mg^{2+}$. The soil bulk density, soil hardness and soil aggregate formation were improved by G+FCM treatments. The dry matter yields of $Sorghum{\times}Sudangrass$ hybrid were significantly increased in proportion to the application rate of FCM. The phosphorus use efficiency showed the highest in the application level of G+FCM 100%, which seemed to be the results of reduced nutrient use efficiency by nutrient immobilization, leaching etc. when applied excessive amount of fresh animal manure.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.4
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• pp.207-215
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• 2002

Changes in salinity, hydraulic conductivity and penetration resistance in a reclaimed tidal land reclaimed in 1986 were studied. The salinity monitoring based on electrical conductivity of saturated extract, ECe, was conducted from 1994, when the land use for experimental crop production started after tile drainage. The site was abandoned since 1999. The hydraulic conductivity was measured by a sand fill auger hole method, and the resistance was measured with a dynamic penetrometer in situ. The averaged ECe in 1994 was $33.7dS\;m^{-1}$ ranging from 25.5 to $44.8dS\;m^{-1}$, and was decreased to $25.7dS\;m^{-1}$ with large range from 0.8 to $70.3dS\;m^{-1}$ before experiment was $1.89{\times}10^{-7}m\;s^{-1}$. It increased to $1.32{\times}10^6m\;s^{-1}$ in the top 20-cm soil with large variability, while it showed $3.44{\times}10^7m\;s^{-1}$ beneath the 20-cm soil depth with less variability. The penetration resistance of the soil ranged from 0.05 to 9.99MPa. The vertical distribution of penetration resistance indicated the hardened layer was developed at the depth of 20~40 cm where the hydraulic conductivity was sharply decreased.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.3
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• pp.172-178
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• 2009

Relation between spatial variation of soil salinity and emergence of five upland crops such as sudan grass, sesbania, barnyard grass, corn and soybean was studied in the three reclaimed lands of Korea during two years from 2007 to 2008. Although soil salinity is vary high at seeding season, desalting treatment by three days-flooding before seeding, reach at favorable level lower than $6dS\;m^{-1}$ of soil salinity for emergence of soiling and forage crops and then plant number emerged(No. $m^{-2}$) was 55~149 for sudan grass, 118~266 for barnyard grass, 46~115 for sesbania, 3~11 for corn and 6~19 for soybean in 2007. However plant number emerged under no desalting treatment varies place by place because of soil salinity difference in 2008. Plant number emerged after seeding according to soil salinity was well expressed as logarithmic function, and sharply decrease with increase of soil salinity. It is accordingly concluded that desalting treatment of flooding before seeding of upland crops is essential for good emergence in the newly reclaimed land from tidal flat.