• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.160-165
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• 2010

To reduce the dose of fertilizers is very important to sustainable production of many horticultural crops, including strawberry. In order to practice the environment friendly agriculture of strawberry cultivation in plastic film house, soil chemical properties of 435 soil samples (232 for loam, 83 for sandy loam, and 120 for silt loam) in Chungnam Province from2008 to 2009 were determined. The average of pH, EC, OM, Av. $P_2O_5$, Ex. $K^+$, Ex. $Ca^{2+}$, Ex. $Mg^{2+}$, and Ex. $Na^+$ was 6.5, 2.28 dS $m^{-1}$, 26 g $kg^{-1}$, 910 mg $kg^{-1}$, 1.09 $cmol_c\;kg^{-1}$, 8.3 $cmol_c\;kg^{-1}$, 2.5 $cmol_c\;kg^{-1}$, and 0.58 $cmol_c\;kg^{-1}$, respectively. The content of Av. $P_2O_5$ in sandy loam soil was significantly higher than silt loam soil, whereas other properties showed no difference between soil texture. The kinds of strawberry cultivars showed no difference in soil chemical properties. The frequency distribution within optimum range of soil chemical properties was 30.6%, 35.4%, 37.0%, 5.3%, 8.5%, 8.5%, and 17.9% for pH, EC, OM, Av. $P_2O_5$, Ex. $K^+$, Ex. $Ca^{2+}$, and Ex. $Mg^{2+}$, respectively. Especially, excessive portion of Av. $P_2O_5$, and Ex. $Ca^{2+}$ were high 86.9%, and 86.0%, respectively. EC values of soil samples were significantly positive correlatoin with all chemical properties except soil pH. In principle component analysis of chemical properties in soil samples, the percentage of variance explained by PC 1 was 38.8%, while PC 2 explained 17.8%of the variance, for a cumulative total of 56.6%. These results were able to distinguish between soil textures and strawberry cultivars. Also, these results considered that understanding of soil chemical properties under using principal component analysis be able to improve amounts of fertilizers for sustainable agriculture in plastic film house.

• Korean Journal of Environmental Agriculture
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• v.7 no.2
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• pp.102-110
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• 1988

This study was designed to find out whether the water quality of Lake Daeho would be suitable for Sgricultural purposes during 1984-1988 perird. Thr results were as follows ; 1. There was an apparent seasonal temperature fluctuation$(6-25^{\circ}C)$ above the entrance of the culvert at the depth of 14m, but the temperature below remained constant at $11,9^{\circ}C$. 2. The yearly water qualities observed at the deepest site by the seadike were 7.4-7.5 pH, 16,800-1,472 ${\mu}mhos/cm$ EC, 9.2-10.8ppm DO, 1.3-2.5ppm DOD, 2.4-5.3ppm COD, 0.22-2.29ppm T-N, 0.01-0.10ppm T-P. 3. The average values of water qualities at the epilimnion in 1988 were 7.6 pH, 1,745umhos/cm EC, 10.8ppm DO, 1.8ppm DOD, 2.4ppm COD, 0.52ppm T-N, 0.05ppm T-P. 4. The salinity of the epilimnion at a 6m depth was 29,000ppm before the final closure of the seadike. It was 11,000 ppm in March 1984, 4,300ppm in March 1985, 2,000ppm in March 1986 and 1987, and 900ppm in March 1988. The salinity of the whole water column decreased from 29.000ppm to 1,200 ppm in March 1988. The average salinity above and below the culvert in 1987 was about 1,300ppm, and 30,000ppm respectively reaching that of seawater. 5. The highest salinity was observed at the epilimnion by the seadike, showing about 5,835ppm in 1984. 6. The seasonal salinity fluctuation was 2,000ppm in May, 800ppm in October, and 485ppm in September 1987. 7. The halocline was observed at the depth of 14m where the entrance of the culvert was located. Therefore, the epilimnion water is suitable for agricultural purposes, and the intake of water from Lake Sapkyo seems to be unnecessary.

• Journal of Soil and Groundwater Environment
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• v.16 no.6
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• pp.133-142
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• 2011

A total of 247 samples were collected from groundwater being used for drinking-water supply, and hydrogeochemistry and radionuclide analysis were performed. In-situ analysis of groundwaters resulted in ranges of $13.7{\sim}25.1^{\circ}C$ for temperature, 5.9~8.5 for pH, 33~591 mV for Eh, $66{\sim}820{\mu}S/cm$ for EC, and 0.2~9.4 mg/L for DO. Major cation and anion concentrations of groundwaters were in ranges of 0.5~227.6 for Na, 1.0~279.3 for Ca, 0.0~9.3 for K, 0.1~100.1 for Mg, 0.0~3.3 for F, 0.9~779.1 for Cl, 0.3~120.4 for $SO_4$, 0.0~27.4 for $NO_3$-N, and 6~372 mg/L for $HCO_3$. Uranium-238 and radon-222 concentrations were detected in ranges of N.D-$131.1{\mu}g/L$ and 18-15,953 pCi/L, respectively. In case of some groundwaters exceeding USEPA MCL level ($30{\mu}g/L$) for uranium concentration, their pH ranged from 6.8 to 8.0 and Eh showed a relatively low value(86~199 mV) compared to other areas. Most groundwaters belonged to Ca-(Na)-$HCO_3$ type, and groundwaters of metamorphic rock exhibited the highest concentration of Na, Mg, Ca, Cl, $NO_3$-N, U, and those of plutonic rock showed the highest concentration of $HCO_3$, and Rn. Uranium and fluoride from granite areas did not show any correlation. However, uranium and bicarbonate displayed a positive relation of some areas in plutonic rocks($R^2$=0.3896).