• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.163-167
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• 2003

Based on the transient finite difference solution of Richards' equation, an infiltration model is developed to analyze temporal variation of precipitation recharge in the region of monsoon climates. Simulation results obtained by using time series data of 20-year daily precipitation and pan evaporation indicate that a linear relationship between the annual precipitation and the annual recharge holds for the soils under the monsoon climates with varying degrees of the correlation coefficient depending on the soil types. A sensitivity analysis reveals that the water table depth has little effects on the recharge for the sandy soil, whereas, for the loamy and silty soils, rise of the water table at shallow depths causes increase of evaporation by approximately 100㎜/yr and a corresponding decrease in recharge. A series of simulations for two-layered soils illustrate that the amount of recharge is dominantly determined by the soil properties of the upper layer, although the temporal variation of recharge is affected by both layers.

• Journal of Korean Society on Water Environment
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• v.24 no.4
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• pp.407-414
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• 2008

This study was conducted to evaluate the heavy metal contamination in the soils of Maehyang-ri inland shooting range area. The texture of the Maehyang-ri inland shooting range soil was sandy. Extraction of heavy metals reached quasi-equilibrium within 6 hours using shaking with 0.1 N HCl. 95% and 94% of extraction efficiency was observed for Cu and Pb in the Maehyang-ri shooting range soils, respectively. And Cu and Pb contamination of level of the T-1 region soil was $114.4{\pm}5.7mg/kg$ and $362.3{\pm}20.5mg/kg$. This may be due to the effects of mineralogical factor, soil particle size and un-residual fractions such as exchangeable, carbonate, Fe-Mn oxide and organic+sulfide.

• Journal of the Korean Society for Railway
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• v.8 no.1
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• pp.57-62
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• 2005

The frost heaving pressure can be a problem for weakening of the railway roadbed material. This study was initiated to investigate the soils frost heaving pressure and physical characteristics(Liquid limit, permeability, SEM analysis) resulting from freezing and freezing-thawing cycle process. Therefore, upon freezing a saturated soil in a closed-system from the top, a considerable pressure was developed. Weathered granite soils, sandy soil were used in the laboratory freezing test which sometimes subjected to thermal gradients under closed-systems. The frost heaving pressure arising within the soil samples and the temperature of the samples inside were monitored with elapsed time. The degree of saturation versus heaving pressure curve is also presented for weathered granite soil and the maximum pressure is closely related to this curve. Based on the laboratory test results, fine-grained soils with strong attractive forces between soil grains md water molecules, and additional water is attracted into the pores leading to further volume changes and ice segregation.

• Current Research on Agriculture and Life Sciences
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• v.13
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• pp.9-16
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• 1995

This study was carried out to investigate the Physico-chemical Properties of Maeye-Dong Experiment Forest Soils. It is important to get fundmental information for establishment of economic and enviromental forest stands. The results obtained from this study were as follows: 1. The range of soil texture was in loamy sand and sandy loam. 2. The pH of Maeye-Dong Experiment forest soils found to be lower than that of Korean brown forests. 3. Most of investigated areas were known to be lack of exchangeable cation and nitrogen. 4. Fertilizer application should be advanced for establishment of economic and enviromental forest stand.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.236-241
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• 2011

Soil microbial diversity was responsible for a strong effect on the chemical properties of orchard soils. This study evaluated a relationship between soil chemical properties and soil microbial diversities at 25 sites in orchard soils in Gyeongnam Province. The average nutrients in the orchard soils were 2.6 times for available phosphorous, 2.3 times for exchangeable potassium and 1.3 times for exchangeable calcium higher compared to recommend concentrations in the orchard soils. Contents of available phosphorous and organic matter in the inclined piedmont soils were higher than those in the other topographical soils (p<0.05). Populations of fungi and fluorescence Pseudomonas sp. in the silt loam soils were significantly higher than those in the sandy loam soils (p<0.05). In principal component analysis of chemical properties and microbial populations in the upland soils, our findings suggested that population of bacteria should be considered as potential factor responsible for the clear orchard soils differentiation. The soil organic matter was significantly negative correlation with population of bacteria whereas was positive correlation with population of fungi in orchard soils.

• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.33-38
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• 2010

To improve the existing nitrogen recommendation method based on chemical properties of soils and to establish new recommendation rates of nitrogen fertilizer due to different types of soils, the application rates of nitrogen fertilizer were examined in different soils of 12 experimental rice paddy fields. The application rates of nitrogen fertilizer estimated by soil-testing were higher than the rates of nitrogen standard recommendation that has been used. The application rates for minimum rice productivity ranged from a low of 168 kg/10a in sandy soil to a high of 315 kg/10a in saline soil. Amounts of nitrogen absorption in rice were proportional to the application amounts of nitrogen fertilizer in soils. Nitrogen use efficiency was the highest, 36.7%, in immatured paddy field and it was inversely proportional to the application amounts of nitrogen. the rice tasty value was the highest in the soils without nitrogen application, and also it was the lowest in the saline soils with or without nitrogen application. As comparing with the nitrogen application rates obtained by the existing nitrogen recommendation method, optimal nitrogen application rates estimated by the standardization of nitrogen application efficiency rate, environmental index, and rice quality were 1.0 fold in the well adapted soil and sandy soil fields, 0.92 fold in the immatured soil field, and 0.83 fold in the saline soil field.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.25-34
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• 1979

To clealify the cause of barley and wheat sterility that occurred 77 / 78 cultivation period in Yeongnam area, a few environmental conditions were analyzed. The results are summarized as follows; 1. During the important growing stages such as meiosis and heading stages of barley encountered with severe droughtiness and unusual low temperature. 2. Soil moisture contents in the double cropping paddy soils were higher than cultivated uplands, and in the subsoils than the surface soils, in the clay soils than the sandy soils, in the northern aspect than the southern aspect of slope, respectively. 3. The sterilizing percentage of barley in the double cropping paddy fields were lower than cultivated uplands, in the alluvial fans and plains were lower than cultivated uplands, in the alluvial fans and plains were lower than in rolling or in foot slopes and the northerm aspect of slopes were lower than southern aspect. 4. The sterilizing percentage in the sandy soils were higher than clay soils and in the soils that have shallower plowing layer and shallower available depth had higher sterility. 5. The sterilizing percentage of barley had negative correlation with soil moisture contents in the surface and subsoils in both of cultivated upland or double cropping paddy fields. 6. The droughtiness that prevailed over reproductive growing stages of barley might be cause the sterility and the severe coldness also could be accelerate the phenomenon.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.239-253
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• 1999

The objective of this study was to determine the effects of various kinds of composts on the change of soil chemical properties in upland soils. Field experiments were conducted in the loam and sandy loam soils. Various kinds of composts such as poultry manure compost(PMC), cow manure compost(CMC), human excrement sludge(HES), and food industrial sludge compost(FISC) were applied annually at rates of 0, 40, and $80Mg\;ha^{-1}$ to soils grown with soybean and maize plants for 4 years during 1994 to 1997. The results of this study were as follows : The continuous application of human excrement sludge decreased soil pH up to 4.4~5.0, while other compost treatments increased soil pH compared with control plot. The EC increased initially and showed their maximum values at 20days after compost application, and then decreased up to 40 days, thereafter kept a certain level. The available phosphorous accumulated at 0~20cm depth in loam soil, and 0~50cm in sandy loam soil. Annual accumulation rates were 17% higher in sandy loam soil than loam soil. The more compost application rates and times, the higher base saturation percentage increased in upland soils. Four year's application at a rate of $80Mg\;ha^{-1}$ per year increased the base saturation percentage to 87~91% compared with 45% at control plot in the loam soil. While in sandy loam soil only three year's application of same rate increased the base saturation percentage to 81~92% compared with 30.4% at control plot. The average annual increasing rate of base saturation percentage at the same application rates of composts were higher in sandy loam soil by 2.0~3.7 times than in loam soil. The application of compost increased the exchangeable Ca, Mg, and K contents of soils by 2, 2~3, and 3~5 times, respectively, compared with the control. The contents of exchangeable canons were high in surface soil. and decreased with increase of soil depths. In the case of heavy metal content, there were no difference at the application of PMC and CMC but Ni. Fe, Zn, Cu was increased a little when the HES applied, and Ni and Cr was increased application with FISC.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.416-431
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• 2000

The objective of this study was to determine the effects of various kinds of composts on the change of soil chemical properties in upland soils. Field experiments were conducted in the loam and sandy loam soils. Various kinds of composts such as poultry manure compost(PMC), cow manure compost(CMC), human excrement sludge(HES), and food industrial sludge compost(FISC) were applied annually at rates of 0, 40, and $80Mg\;ha^{-1}$ to soils grown with soybean and maize plants for 4 years during 1994 to 1997. The results of this study were as follows : The continuous application of human excrement sludge decreased soil pH up to 4.4~5.0, while other compost treatments increased soil pH compared with control plot. The EC increased initially and showed their maximum values at 20days after compost application, and then decreased up to 40 days, thereafter kept a certain level. The available phosphorous accumulated at 0~20cm depth in loam soil, and 0~50cm in sandy loam soil. Annual accumulation rates were 17% higher in sandy loam soil than loam soil. The more compost application rates and times, the higher base saturation percentage increased in upland soils. Four year's application at a rate of $80Mg\;ha^{-1}$ per year increased the base saturation percentage to 87~97% compared with 45% at control plot in the loam soil. While in sandy loam soil only three year's application of same rate increased the base saturation percentage to 81~92% compared with 30.4% at control plot. The average annual increasing rate of base saturation percentage at the same application rates of composts were higher in sandy loam soil by 2.0~3.7 times than in loam soil. The application of compost increased the exchangeable Ca, Mg, and K contents of soils by 2, 2~3, and 3~5 times, respectively, compared with the control. The contents of exchangeable cations were high in surface soil, and decreased with increase of soil depths. In the case of heavy metal content, there were no difference at the application of PMC and CMC but Ni, Fe, Zn, Cu was increased a little when the HES applied, and Ni and Cr was increased application with FISC.

• Journal of Ginseng Research
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• v.13 no.1
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• pp.84-91
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• 1989

This study was conducted to Investigate the effects of physico-chemical soil properties on the growth and yield of ginseng. 1 In the field survey, the yields of 6 year old ginseng were 2.46 Kg/3.3$m^2$, 2.13 Kg/3.3$m^2$, 1.44 Kg/3.3 $m^2$ in clay loam, loam and sandy loam soils, respectively 2. The missing plant rate for il year old ginseng were 33.6% and 51.6% in clay loam and sandy loam soils, respectively : the stem length and stem diameter of ginseng plants in sandy loam soil were smaller than those in clay loam soil. 3. Soil aggregation and porosity we're slightly higher in 6 year old ginseng fields than in 2 year ones. 4. Inorganic-N increased in 2 year and 3 year old ginseng fields reaching up to 100-120ppm, however it 1 decreased to 75 ppm, 34 ppm and 25 ppm in 4, 5 and 6 year old ginseng fields, respectively, It varied 1 more greatly in sandy loam soil than in clay loam. 5. The $P_2O_5$, K, Ca, and Mg contents differed little with plant age. Sandy loam had high N and $P_2O_5$ contents but low cation contents. 6. The yield of 6 year old ginseng fields were significantly correlated with clay contents and porosity. The missing Plant rate of 6 year old ginseng had a positive correlations with sand. and N contents.