• Korean Journal of Soil Science and Fertilizer
• /
• v.30 no.2
• /
• pp.152-160
• /
• 1997

In order to monitor the content of heavy metals of soil and vegetable in the plastic film house, five hundred and twenty two soil, and 147 vegetable samples grown under plastic film house were collected for the analysis of heavy metals. The average contents of Cd, Cu, Pb, Zn and As in surface soil were 0.208, 3.69, 2.49, 23.3 and 0.65mg/kg, respectively. Cu and Zn contents of the soil were higher than those values measured for upland soils in 1989, however, these contents were lower than "Countermeasure values" (Cd:4, Cu:125, Pb:300, and As:15mg/kg in soil) for soil contamination indicators described in Soil Environmental Conservation Act of Korea(1996). The contents of Cd, Cu and Zn increased with increasing years of cultivation. The contents of Cd, Cu, and Zn in soils received pig manure compost were higher than those received the poultry or barn yard manure compost. The average contents of Cd, Cu, Pb, Zn and As in fresh vegetable plants ranged from 0.015 to 0.047, 0.341 to 0.802, 0.080 to 0.356, 1.08 to 8.04 and 0.021 to 0.059mg/kg, respectively.

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.3
• /
• pp.204-214
• /
• 1993

The purpose of this study was to elucidate the chemical changes and formation of sulfur minerals following reduction and subsequent oxidation of the acid sulfate soils derived from the fluvio-marine plains in Gimhae area. Changes in pH, Eh and water soluble $SO_4$, Fe, Al, K, na and Ca were determined in the soil under the reduced and oxidized conditions. These chemical properties were related to the formation of the pyrite and jarosite, the major sulfur minerals in the acid sulfate soils. On incubation, suspension pH tended to increase with decreaseing Eh in the reduction periods. Jarosite formation was favored by maintaining continuous low pH(below 4.0) and high Eh(above 400mV) during the oxidation periods, however, the conditions were not favorable for the soils with $Ca(OH)_2$. Water soluble K increased by reduction but decreased by oxidation, while the jarosite of the soil with $Ca(OH)_2$ was dissolved even under the oxidation conditon, resulting in rapid increase of water soluble K. The water soluble Ca decreased rapidly, indicating that gypsum was formed with $Ca(OH)_2$ during the oxidation periods. The formation of jarosite was favored by the oxidation condition, and hindered by the reduction condition. But the formation of pyrite was favored by reduction and hindered by oxidation. When the troll was treated with $Ca(OH)_2$, Jarosite was dissolved in both oxidized and reduced conditions.

• Korean Journal of Soil Science and Fertilizer
• /
• v.11 no.2
• /
• pp.61-66
• /
• 1979

This experiment was conducted to find out the simple and economical method to improve physical properties of the soil that was very poor for the establishment of orchard. Jeonnam clay loam soils distributed mainly on rolling and hill side slope, were treated with the explosion of two kinds of dynamite at the depth of 1 m. The change of physical properties was investigated vertically and horizontally after soil profile had settled to some extent. The results were summarized as : 1. The original soil was very high in bulk density and soil hardness. Total porosity and aeration porosities were lower than critical level providing root elongation. It was more apparent in the subsoil than in the surface soil. 2. It was recognized that soil mass destruction and cracking by dynamite explosion decreased soil bulk density and soil hardness and increased porosity, especially non-capillary pores. 3. Effective radius of the improved physical properties by explosion with two dynamites was 100cm at 60cm depth and 30cm at 80cm depth. But with the use of three dynamites it was 100cm at 80cm depth. 4. It was thought that soil mass destruction and cracking caused by explosion was uneven in the two dynamites, and three dynamites was more effective to improve physical properties evenly. 5. With the use of two dynamites, Ammonium explosive was superior to gelatin dynamite.

• Korean Journal of Soil Science and Fertilizer
• /
• v.13 no.2
• /
• pp.65-70
• /
• 1980

This experiment was aimed at selecting the most suitable dispersing agent to the Korean soils. The particle size distribution of 18 soil samples representing the great soil groups in Korea was analysed with 5 different dispersing agents by pipette-method. Passing percent of 0.05, 0.02 and 0.002mm in diameter was used for the comparision of the dispersion capacity of chemical agents. The results obtained are as follows; 1. The influence of chemical agents on dispersion seemed to be greater to finer soil particles. The passing percents of 0.002mm showed a great differences according to the chemical agents used, while little differences was observed in those of 0.05mm. 2. It was showed that sodium pyrophosphate had the highest dispersion capacity for the most of Korean soils, the dispersion capacity of sodium hexametaphosphate was also high enough except for volcanic ash soils. 3. It was recommendable that sodium hexametaphosphate could widely be used as a dispersing agent in the routine analysis of soil particle size distribution except for the Volcanic ash soils. 4. The dispersion of Volcanic ash soils was rather poor when chemical agents used. Therefore, special care should be taken for the dispersion of allophane soils.

• Korean Journal of Soil Science and Fertilizer
• /
• v.30 no.3
• /
• pp.265-271
• /
• 1997

The salt accumulation, and chemical properties of 90 samples of the plastic film house soil in the area of Cheongju and Chungju were surveyed. Soil textural distribution of soil samples was 30% for sandy loam, 27% for loam and 43% for silty loam. Percentage distribution of electrical conductivity(EC) of surface soil was 23% below $2dS\;m^{-1}$, 30% for $2{\sim}4dS\;m^{-1}$, 25% for $4{\sim}6dS\;m^{-1}$ and 22% over $6dS\;m^{-1}$. Salt affected soil, which EC was higher than $4dS\;m^{-1}$, covered nearly 50% of all field surveyed. However subsoils(20~30cm) below $2dS\;m^{-1}$ was 68%. Salts in plastic film house soil was accumulated by increasing the cultivation period. After 5 years of cultivation electrical conductivity in plastic house soil was generally higher than $4.47dS\;m^{-1}$ in EC that was 2.8~5.6 times higher than that in the field soil in the outside of plastic film house. As the result of temporary removal of plastic film cover from the house during the rainy summer season, salt content in soil was decreased from $3.54{\sim}7.36dS\;m^{-1}$ to $0.71{\sim}2.92dS\;m^{-1}$ in EC due to the desalinization by runoff and percolating water. Contents of $NO_3-N$, $SO_4-S$ and Cl in plastic film house soil were 2.5. 7.0 and 3.4 times higher than those of open field respectively.

• Korean Journal of Environmental Agriculture
• /
• v.5 no.1
• /
• pp.11-23
• /
• 1986

Soils and rice plants in wastewater irrigated area of the Mangyeong River receiving waster from the Jeonju Industrial Complex and municipal sewage were sampled at two depths to assess the nature and content of Cd, Cu, Pb and Zn, particularly with respect to distance from wastewater source. For metal levels of soils in these area, no difference in the heavy metal contents between the surface and the subsurface soils was found. Total contents of Cu, Pb and Zn in soils were negatively correlated with distance from the source. A positive correlation was found between contents of total and 0.1N-HCl extractable or $1N-CH_3COONH_4$ extractable heavy metals in surface soils of these area. Total contents of heavy metals in soils were positively correlated with clay, soil organic matter and cation exchange capacity. Heavy metal contents of brown rice sampled at the Jeon-ju Industrial Complex area ranged from 0.15 to 0.91 ppm for Cd, from 1.13 to 5.68 ppm for Cu, from 0.22 to 7.16 ppm for Pb and from 11.74 to 38.66 ppm for Zn. Negative correlation was found between the contents of Cd, Cu, Pb, and Zn in the brown rice and the distance from the source. The contents of Cd, Cu and Zn in rice straw were positively correlated with those in the brown rice.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.42 no.5
• /
• pp.564-570
• /
• 1997

Field experiments were carried out to investigate the effects of different residue treatment of vetch sward on soil improvement, rice growth and grain yield from 1995 to 1996. With Chinese milkvetch, pH, Ca, and Mg of paddy soil were increased in subsoil(10~20cm soil depth), and organic matter, P$_2$ $O_{5}$, and K were increased in top soil (0~10cm soil depth). Redox potential of the paddy soil with milkvetch residue was severely reduced at earlier flooding period, and recovered gradually as rice growth continued. Weeds were more abundant in the paddy with unchanged vetch stand. The most dominant weed species in the paddy soil with vetch sward residue was Echinochloa crus-galli, followed by Leersia japonica, Polygonum hydropiper in the order of abundance. Seedling establishment ratio of rice directly sown over vetch-sward was lower than in conventional tillage paddy(no-vetch, tilled) condition. Rice growth pattern, however, was not significantly affected by vetch sward treatments. The number of tillers per square meter and plant height at heading date were not significantly different among the vetch-sward treatments. Grain yield was the highest in plough of vetch vegetation, followed by conventional (no-vetch, tilled), live-mulching of vetch, vetch-removed, and vetch-desiccated by weedcide. The whole grain rice yield was the lowest in vetch-desiccated by weedcide.

• Journal of the Korean GEO-environmental Society
• /
• v.15 no.6
• /
• pp.17-29
• /
• 2014

A remedial investigation was conducted at five military training ranges in northern Gyeonggi province to collect information necessary for the design of on-site treatment facilities for the abatement of explosive compounds release to the environment. These information includes (i) identification of dominant explosive compounds in each range, (ii) discharge/migration routes, and (iii) contaminant distribution in particle size fraction and settling velocity of the soils. The results of investigation showed that TNT and RDX are the major contaminants but the extent of contamination varied depending on the types of military training practices and topography of the site. RDX was also detected in the subsurface soil and in the nearby stream within the training ranges, suggesting release of contaminants to streams. The median concentrations of explosives in the surface soil were less than 20 mg/kg despite several 'hot spots' in which explosives concentrations often exceeds several hundred mg/kg. The average clay contents in the soil of target area was less than 5 % compared to 12 % in the control, indicating loss of smaller particles by surface runoff during rainfall due to lack of vegetative land cover. Analysis of explosive compounds and particle size distribution showed that the amount of explosive compounds in soil particles smaller than 0.075 mm was less than 10 % of the total. Settling column tests also revealed that the quantity of explosive compounds in the liquid phase of the effluent was greater than that in the solid phase. Therefore, pre-treatment of particulate matter in surface runoff of shooting range with a simple settling basin and subsequent effluent treatment with planted constructed wetlands as polishing stage for explosives in the aqueous phase would provide the shooting ranges with a self-standing, sustainable, green solution.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.6
• /
• pp.473-477
• /
• 2001

Chinese milkvetch (Astragalus sinicus L.) has been traditionally used as a green manure supplying mineral N and organic matters to soil. In rice-Chinese milkvetch interrelay cropping system, three rice cultivating methods (no-till direct seeding, no-till transplanting, and tillage transplanting) were evaluated for stand reestablishment without reseeding Chinese milkvetch with two cropping times (May 25 and June 4) for two years. Chinese milkvetch incorporated was decomposed rapidly in the first week. Decomposition was fast in topsoil than in subsoil. Natural milkvetch reestablishment (NMR), following harvest of no-till-direct-sown rice was good enough to cover the paddy field in both cropping times, but rice yield of this method was lower than that of transplanted rice on paddy field without milkvetch cultivation. Even though good NMR was secured in no-till rice transplanting, the shoot of milkvetch should be removed before machine-transplanting of rice seedlings. NMR was better in rice cropping at the mid-ripening stage of milkvetch (June 4) than at the late-bloom stage (May 25). Rice yield was higher in tillage transplanting at the mid-ripening stage of milkvetch (June 4) than in the other rice cropping method.

• Korean Journal of Soil Science and Fertilizer
• /
• v.30 no.1
• /
• pp.94-98
• /
• 1997

This experiment was conducted to investigate the distribution of the soil microflora of Daekwanryung highlands of Kwangwon Province. It was found that soil microorganisms each as Bacteria, Actinomycetes, Fungi, Pseudomonas spp. and Erwnia sp. were mostly in the top 0-15 cm profile. It also was found that soil microflora population was affected in many ways by kind of cropping plant. The number of Erwinia sp. that is one of the soil born plant pathogenic bacteria was more abundant in potato field than chinese cabbage soil. It was also studied difference of mountain and grassland soils from cropping soils.