• Journal of the Korean Institute of Landscape Architecture
• /
• v.35 no.3
• /
• pp.105-113
• /
• 2007

This study was conducted to analyze the effects of environmental factors such as soil moisture, light intensity, temperature and humidity on changes in cambial electrical resistance. To improve data quality, cambial electrical resistance was continuously measured at fixed points by using a data logger isolated from alternating current. The relationship between environmental factors and changes in cambial electrical resistance was also analyzed. The results are as follows: 1. Cambial electrical resistance is highly correlated to the temperature of the measured area(r=-0.934). Therefore, temperature compensation is needed to analyze the effects of other environmental factors on cambial electrical resistance changes. 2. If temperature is compensated for, the change of cambial electrical resistance is highly correlated to water vapor pressure(r=-0.836). 3. If temperature and humidity are compensated for, the change of cambial electrical resistance is highly correlated to intensity of light(r=-0.738). 4. Diurnal deviation of soil water potential is not more significantly related than the change of cambial electrical resistance. However, in the long-term, soil water potential and cambial electrical resistance are highly correlated(r=-0.831). This indicates that soil moisture significantly influences the long-term change of cambial electrical resistance.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2003.10a
• /
• pp.559-562
• /
• 2003

The results and discussions of surveyed case site at constructed steel pile in potential acid sulfate soil were as follows. Topography at surveyed site was local alluvial valley and that site soils was classified as BanGog and YuGye series as detailed soil surveyed results in RDA and soil texture was Clay/Clay Loam. Soils pH was neutral, which was average 7.5 but much decreased to average 4.2 after $H_2O_2$ treatment. Organic matter and sulfate ions contents were very rich. The corrosion was severe at ground water fluctuation depth. Deposits colored black were attached to steel pile surface, which because of violent reaction in treatment HCI solution, were guessed as corrosion products (FeS) reduced by sulfate reducing bacteria(SRB). Consequently, main cause was thought microbiologically induced corrosion at this site where there is ground water fluctuation occurring oxidation and reduction reactions in turn and the soil is potential acid sulfate soil.

• Journal of Bio-Environment Control
• /
• v.16 no.3
• /
• pp.174-179
• /
• 2007

Although the relationship between fermentation and factors such as soil water, redox potential, rootstocks and climatic conditions has been reported, its mechanism of fermentation is still not clear. Transpirations of leaf and fruit at different climatic conditions, influence of soil water potential and atmospheric vapor pressure deficit (VPD) on fermentation were evaluated. Transpiration rate decreased with decreasing soil temperature and soil water potential. Low VPD conditions which occurred during low air temperature and high humidity also decreased transipration rate. These data exhibit that fruit water balance affected by various factors relate to transpiration. Our results also indicate that high hydraulic conductance of root, high soil water potential and low VPD condition exert a significant effect on fermention of oriental melon and so called "water filled fruit".

• Korean Journal of Medicinal Crop Science
• /
• v.4 no.4
• /
• pp.288-293
• /
• 1996

This study was investigated to obtain basic information for the development of irrigation plans in upland cultivation of Wasabi. Changes of stomatal conductivity and photosynthetic rate of Wasabi, and of the soil water potential during withholding watering were analysed. The stomatal conductivity of Wasabi at $1000{\mu}Em^{-2}s^{-1}$ light intensity was $70mmolem^{-2}s^{-1}$, which was about 49% lower than that of Chinese cabbage, $138mmolem^{-2}s^{-1}$. The temporal changes of light intensity during the daytime did not influence the stomatal conductivity. The soil water potential that decreased stomatal conductivity in Wasabi was about - 50kPa at 10 AM, and about - 30kPa at 3 PM. The photosynthetic rate of Wasabi at$1000{\mu}Em^{-2}s^{-1}$ light intensity was $7.6mgdm^{-2}hr^{-1}$, which was about 50% lower than that of Chinese cabbage, $15.3mgdm^{-2}hr^{-1}$. The duration required for a stable photosynthetic rate was longer in Wasabi than in Chinese cabbage. The soil water potential that decreased photosynthetic rate in Wasabi was about - 50kPa at 10 AM, and about - 30kPa at 3 PM. The stomatal conductivity and photosynthetic rate showed significant positive correlation at various soil water potential. The results indicated that irrigation in wasabi could be done during the daytime when the soil water potential is above - 30kPa, which does not decrease stomatal conductivity and photosynthesis in Wasabi.

• Journal of Korean Society on Water Environment
• /
• v.31 no.6
• /
• pp.693-699
• /
• 2015

It has been known that torrential rainfall events have been occurring worldwide due to climate change. The accelerated soil erosion has caused negative impacts on water quality and ecosystem of receiving waterbodies. Since soil security issues have been arising in various areas of the world, intensive interests have been given to topsoil management in Korea. Thus in this study, Web GIS-based computing system of physical, chemical, and biological topsoil quality indices were developed. In this study, five soil quality maps at national scale and top soil erosion potential were prepared for evaluation of soil quality based on soil erosion potential. For this system, the open source Web GIS engine, OpenGeo, was used as core engine of the system. With this system, decision makers or related personnel in areas of soil erosion Best Management Practices (BMPs) would be able to find the most appropriate soil erosion BMPs based on soil erosion potential and soil quality at the area of interest. The Web GIS system would be efficiently used in decision making processes because of ease-of-use interface and scientific data used in this system. This Web GIS system would be efficiently used because this system could provide scientific knowledge to decision makers or stakeholders. Currently various BMP database are being built to be used as a decision support system in topsoil management and topsoil quality areas.

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.4
• /
• pp.284-288
• /
• 1993

Tow Kinds of Soils, vertisol and alfisol, were selected and analyzed pore space distribution(PSD) by mercury intrusion method and soil water potential after freeze-drying from different water conditions, such as 0.033MPa, 1.5MPa and ovendry. The PSD values measured by mercury intrusion method were higher in large pores than the values from soil water potential. Also, there were big differences of PSD by the changes of the water content befor freeze-drying.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.4
• /
• pp.241-244
• /
• 2000

This experiment was conducted to evaluate the effect on evapotranspiration and yield of soybean according to different soil water conditions, and to find the optimum time and amount for irrigation in soybean cultivation. The difference between potential evapotranspiration (PET) and maximum evapotranspiration (MET) during growing season of soybean planted in lysimeter was higher during reproductive stage than during vegetative one. The maximum crop coefficient was obtained at beginning seed stage of soybean. Soil water coefficient of irrigation treatment was higher than that of non-irrigation treatment during soybean growth stage in field experiment. Grain yield was highest in lysimeter due to its high water use efficiency and evapotranspiration rate.

• Journal of Applied Biological Chemistry
• /
• v.43 no.3
• /
• pp.170-175
• /
• 2000

A pot-lysimeter experiment was conducted with 3-year-old 'Tsugaru' apple (Malus domestica Borkh) trees to examine the changes in oxygen diffusion rate (ODR) with lateral flow velocity of water through soil. The influence of lateral water flow velocity on water relations and elemental content in leaf, and sap temperature distribution patterns of the xylem of trees were also determined. Trees were grown under four soil water regimes: (1) fast laterally flowing (FWT, $2.50{\times}10^{-4}cm\;s^{-1}$), (2) slow laterally flowing (SWT, $0.25{\times}10^{-4}cm\;s^{-1}$), and (3) stagnant water table (WLT) at 60-cm, and (4) drip-irrigation at -40 kPa of soil matric potential as a control. The rate of $O_2$ diffusion converged near $2{\times}10^{-3}g\;m^{-2}\;min^{-1}$ for FWT and control soils, but decreased below $1{\times}10^{-3}g\;m^{-2}\;min^{-1}$ 40 days after treatment (DAT) for WLT soils. For SWT soils, however, the ODR at 15 cm below the soil surface was similar to that of control, but at 45 cm below the soil surface, ODR was similar to that of the WLT treatment. Leaf water potential of FWT and SWT plants was similar to that of control plants, but the values for SWT plants declined by 98 DAT. Leaf water potential of WLT plants decreased from -1.86 MPa (9 DAT) to -2.41 MPa (59 DAT) and finally down to -2.70 MPa. The sap temperature measured at 1100-hr was lowest at top and highest at bottom for FWT and control plants, but this pattern of SWT and WLT plants was disturbed from 29 DAT. However, for SWT plants, such thermal disturbance of sap temperature disappeared from 63 DAT.

• Journal of Korean Society of Forest Science
• /
• v.42 no.1
• /
• pp.59-66
• /
• 1979

This experiment was carried out to know the effects of soil water potential of cutting bed and relative humidity on the rooting of stem cutting in the field plots. The results obtained were as follows; 1. The most number of the rooted cutting was found from 70 to 80% of relative humidity in Spring and from 90 to 100% in Summer respectively. 2. It was found that the number of rooted cutting was the least in the range of 0 to-0.006 bar of soil water potential of cutting bed in the case of Spring cutting, whereas in Summer the number of the rooted cutting was the most one in the range of -0.049 to -0.124 bar of soil water potential of cutting bed. 3. High signification was recognized between the relative humidity and the number of the rooted cutting only in the Spring cutting, but that of soil water potential and the number of the rooted cutting was found to be significant in every season.

• Journal of Environmental Science International
• /
• v.4 no.5
• /
• pp.427-435
• /
• 1995

In order to discuss the differences among the SMP(Surface Moisture Availability Parameter), by previous researchers on the basis of their own theoretical and empirical background, we assessed the SMP according to the soil types and volumetric soil water contents. The results are as follows. There are differences among all the five SMAPs. There's a tendency that the larger grain size, the higher value of parameters. And they divided into two groups for their value: one group has parameters with exponential function and the other with cosine and linear function. The maximum difference between the two groups appears when the volumetric soil water contents are 0.07m3m-3 for sand, 0.l1m3m-3 for loam, 0.12 for clay, and 0.13m3m-3 for silt loam. So, these differences must be considered when we estimate the surface evaporation rate. From field data, the paddy field soil around Junam reservoir is classified as a silt has high wetness, 0.56. So, the parameter obtained from the field measurement is much higher than that of Clapp and Hornberger(1978)'s Table. This study treated the SMP for a certain point of time in winter season. But if we measured the soil water contents continuously, we could obtain better time-dependent parameter. Key words : SMAP(Surface Moisture Availability Parameter), Paddy field, Volumetric soil water content, Evaporation, Capillary potential.