• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.502-509
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• 2011

It is important to determine optimum soil covering depths for tree survival and growth because soil covering depths for establishing tree planting bases in coastal reclaimed lands are related to the costs for soil collection, transportation and land reclamation. The objectives of this study were carried out to determine optimum soil covering depths for the normal growth of planted trees in a coastal reclaimed land. The study sites were located in Asan National Industrial Complex in Pyeongtaek City, Gyeonggi-do. Four tree species (Pinus thunbergii, Chamaecyparis pisifera, Zelkova serrata, Quercus acutissima) with one hundred eighty trees of each species were planted in various depths of soil covering (no soil covering, 0.5 m, 1.5 m, 2.0 m soil covering treatments) on April 1998, and the tree growth patterns were measured on September 2000. The change of soil properties, tree mortality rate, root collar diameter and height growth were measured from each soil covering depth treatment on September 2000. Soil pH, EC, exchangeable cations ($K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$), anion $Cl^-$, and base saturation increased with decreased soil covering depths. The mortality rates of tree species showed decreased with increased soil covering depths. The height growth of tree species increased with increased soil covering depths. Height growth of Pinus thunbergii was significantly different between the soil covering depth below 0.5m and other three covering depths, while the growth of other species (C. pisifera, Z. serrata, Q. acutissima) was significantly higher in soil covering depths below 1.5 m than in other soil covering depth treatments. The root collar diameter growth of all tree species showed increasing trends with increased soil covering depths. It is recommended to cover the soil depths above 1.5 m to decrease mortality and to stimulate the tree growth of C. pisifera, Z. serrata and Q. acutissima, while P. thunbergii which is a salt tolerate species could be planted in the 1.0 m soil covering depth.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1112-1117
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• 2011

This study was conducted to recommend nitrogen (N) top dressing based on soil nitrate content for leaf perilla under forcing culture in Gumsan-gun and Milyang-si. Experimental design was the randomized complete block design for five N fertilization levels and conventional fertilization. Dry weight, nitrogen uptake, and the node number of leaf perilla were measured and soil nitrate contents were analyzed monthly. The amount of nitrogen uptake for growth of a node with two leaves was $2.2kg\;10a^{-1}$ for Gumsan site and $3.5kg\;10a^{-1}$ for Milyang site. Lower level of soil nitrate N concentration for standard N fertilization was determined as $10mg\;kg^{-1}$ for both sites. Soil depth, bulk density, utilization rate of soil nitrate N, and the amount of N uptake for growth of a node with two leaves were considered for calculation of upper level of soil nitrate N concentration. The upper levels of soil nitrate N concentration for no N fertilization were determined as $30mg\;kg^{-1}$ for Gumsan site and as $40mg\;kg^{-1}$ for Milyang site. Consequently the recommendation equations for the N top dressing were Y=-0.157X+4.71 for Gumsan site and Y=-0.1667X+6.6667 for Milyang site.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.717-721
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• 2011

In case of plastic film greenhouses cultivating fresh vegetables on paddy soil, soil characteristics must be considered as more important factor than any other factors. Generally after the four years of cultivation, soils tend to increase electrical conductivity value, nutrient unbalance and soil pests. As a result, degradation of agricultural products occurred, therefore it is necessary to improve soil conditions. In this study, yield and economic cost of cucumber were analyzed. The best soil conditions for cucumber cultivation were alluvial or valley in soil topology, moderately or poorly drainage in soil drainage classes, coarse loamy soil in texture. In addition, rich-sunlight and-deep groundwater would be proper for the cucumber cultivation. Good environmental managements of plastic film greenhouse were as follows. The temperature needed to be adjusted three times. The optimal daytime temperature could be $22{\sim}28^{\circ}C$, the one from 12 until night could be $14{\sim}15^{\circ}C$, and the temperature from 24 to sunrise could be $10{\sim}12^{\circ}C$. During plant growth period, soil moisture content was as low as 10~15%, and it needed to be maintained as 15~20% during reproductive growth period. To control pests, catch crop cultivation and solar treatment were carried out, after those EC was reduced and the root-knot nematode was controled too. Cucumber yield from the plot with improved soil managements increased to $158.4Mg\;ha^{-1}$, but plot with successive cropping injury yielded $140.3Mg\;ha^{-1}$. The income from the plot with improved soil managements was 215,676 thousand won $ha^{-1}$, the plot with successive cropping injury was 131,649 thousand won $ha^{-1}$. Income rate of each plot was 51.8% and 38.4%, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.702-708
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• 2011

There are considerable areas of wet paddy fields in Korea that requires improvement of its drainage system. In poorly drained sloping paddy fields, upland crops can be damaged by either rainfall or capillary rise of the water table caused by percolating water beneath the upper fields during summertime rainy season. The purpose of this study is to evaluate excess water stress of soybean yield by drainage systems. Four drainage methods namely open ditch, vinyl barrier, pipe drainage and tube bundle were installed within 1-m position at the lower edge of the upper paddy fields. Stress Day Index (SDI) approach was developed to quantify the the cumulative effect of stress imposed on a soybean yield throughout the growing season. SDI was determined from a stress day factor (SD) and a crop susceptibility factor (CS). The stress day factor is a measure degree and duration of stress of the ($SEW_{30}$). The crop susceptibility factor (CS) depends of a given excess water on crop stage. The results showed that SDI used to represent the moisture stress index was most low on the pipe drainage 64.75 compared with the open ditch 355.4, vinyl barrier 271.55 and tube bundle 171.55. Soybean grain yield increased continuously with the rate of 3% in Vinyl Barrier, 32% in Pipe Drainage and 16% in Tube Bundle.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1071-1079
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• 2011

In this study, coal combustion ash (CCA) was evaluated for its stabilization effect on acidic mine waste with column experiment. Total of six treatments were installed depending on mixing ratio between coal wastes and CCA (0, 20, 40%) and mixing method (completely mixing and layered). Artificial acidic rain (pH 5.6) was used for feeding solution with flow rate of $0.05mL\;min^{-1}$. Result showed that higher pH of leachate was observed as more CCA was mixed. The highest pH in leachate was measured when 40% of CCA was mixed with coal waste (pH of 5.8). Also, complete mixing with CCA and coal waste was more effective to increase the pH of leachate than layered treatment. Regarding the reduction of soluble Fe amount, the highest efficiency (78%) was observed when 20% of coal ash was completely mixed with mine waste. Based on those result, optimum mixing ratio of coal ash with mine waste can be ranged 20-40% depending on environmental circumstances in the field.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.434-441
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• 2011

To improve T-N and T-P removal efficiencies, removal efficiencies of pollutants in full-scale livestock wastewater treatment plant by natural purification method with water plant filtration and activated sludge beds were investigated under different re-injection rates and injection methods of livestock wastewater. The removal rates of COD, SS, T-N, and T-P in effluent in full-scale livestock wastewater treatment plant were in the order of 30% < 70% ${\leq}$ 100 % at different re-injection rates. The removal rates of pollutants in effluent in full-scale livestock wastewater treatment plant were higher as re-injection rate of livestock wastewater increased. Removal rates of COD, SS, T-N, and T-P by continuous injection were slightly higher than those by intermittent injection method in full-scale livestock wastewater treatment plant. Removal rates of COD, SS, T-N, and T-P by continuous injection method in full-scale livestock wastewater treatment plant with water plant filtration and activated sludge beds were 99.5, 99.8, 99.0 and 99.8%, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.789-792
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• 2010

Major impacts of climate change expert that soil erosion rate may increase during the $21^{st}$ century. This study was conducted to assess the potential impacts of climate change on soil erosion by water in Korea. The soil loss was estimated for regions with the potential risk of soil erosion on a national scale. For computation, Universal Soil Loss Equation (USLE) with rainfall and runoff erosivity factors (R), cover management factors (C), support practice factors (P) and revised USLE with soil erodibility factors (K) and topographic factors (LS) were used. RUSLE, the revised version of USLE, was modified for Korean conditions and re-evaluate to estimate the national-scale of soil loss based on the digital soil maps for Korea. The change of precipitation for 2010 to 2090s were predicted under A1B scenarios made by National Institute of Meteorological Research in Korea. Future soil loss was predicted based on a change of R factor. As results, the predicted precipitations were increased by 6.7% for 2010 to 2030s, 9.5% for 2040 to 2060s and 190% for 2070 to 2090s, respectively. The total soil loss from uplands in 2005 was estimated approximately $28{\times}10^6$ ton. Total soil losses were estimated as $31{\times}10^6$ ton in 2010 to 2030s, $31{\times}10^6$ ton in 2040 to 2060s and $33{\times}10^6$ ton in 2070 to 2090s, respectively. As precipitation increased by 17% in the end of $21^{st}$ century, the total soil loss was increased by 12.9%. Overall, these results emphasize the significance of precipitation. However, it should be noted that when precipitation becomes insignificant, the results may turn out to be complex due to the large interaction among plant biomass, runoff and erosion. This may cause increase or decrease the overall erosion.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.945-953
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• 2010

This study was conducted to evaluate the effect of swine liquid manure (SLM) on rice grown in Yeonggwang-gun in 2008. The treatments consisted of SLM and chemical fertilizer (CF) based on the recommended amount of nitrogen (11 kg N $10a^{-1}$). The Total N content of the SLM used was 2,881 mg $L^{-1}$. Plant height at the early stage of growth and tiller number were not significantly different between plots applied with swine liquid manure and those with chemical fertilizer in all areas. Plant height at the later stage of growth, lodging and yield were not significantly different between plots applied with swine liquid manure and those with chemical fertilizer in three areas (Baeksu, Gunnam, Beopseong). Plant height at the later stage of growth, as well as lodging were higher in SLM plots than in chemically fertilized plots in Yeonggwang and Yeomsan. However, grain yield was lower in SLM plots than in chemically fertilized plots in these areas. Soil organic matter content and exchangeable cations increased in the swine liquid manure applied plots. Moreover, heavy metal content did not increase in the plots treated with swine liquid manure. Further research to determine the suitable rate of swine liquid manure is needed to reduce lodging damage and to increase the yield and quality of rice.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.399-407
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• 2009

Laser induced breakdown spectroscopy(LIBS) is an simple analysis method for directly quantifying many kinds of soil micro-elements on site using a small size of laser without pre-treatment at any property of materials(solid, liquid and gas). The purpose of this study were to find an optimum condition of the LIBS measurement including wavelengths for quantifying soil elements, to relate spectral properties to the concentration of soil elements using LIBS as a simultaneous un-breakdown quantitative analysis technology, which can be applied for the safety assessment of agricultural products and precision agriculture, and to compare the results with a standardized chemical analysis method. Soil samples classified as fine-silty, mixed, thermic Typic Hapludalf(Memphis series) from grassland and uplands in Tennessee, USA were collected, crushed, and prepared for further analysis or LIBS measurement. The samples were measured using LIBS ranged from 200 to 600 nm(0.03 nm interval) with a Nd:YAG laser at 532 nm, with a beam energy of 25 mJ per pulse, a pulse width of 5 ns, and a repetition rate of 10 Hz. The optimum wavelength(${\lambda}nm$) of LIBS for estimating soil and plant elements were 308.2 nm for Al, 428.3 nm for Ca, 247.8 nm for T-C, 438.3 nm for Fe, 766.5 nm for K, 85.2 nm for Mg, 330.2 nm for Na, 213.6 nm for P, 180.7 nm for S, 288.2 nm for Si, and 351.9 nm for Ti, respectively. Coefficients of determination($r^2$) of calibration curve using standard reference soil samples for each element from LIBS measurement were ranged from 0.863 to 0.977. In comparison with ICP-AES(Inductively coupled plasma atomic emission spectroscopy) measurement, measurement error in terms of relative standard error were calculated. Silicon dioxide(SiO2) concentration estimated from two methods showed good agreement with -3.5% of relative standard error. The relative standard errors for the other elements were high. It implies that the prediction accuracy is low which might be caused by matrix effect such as particle size and constituent of soils. It is necessary to enhance the measurement and prediction accuracy of LIBS by improving pretreatment process, standard reference soil samples, and measurement method for a reliable quantification method.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.1040-1046
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• 2010

This research is composed of a series of survey of existing plants species by classifying biotope type of agro-ecosystem of Guksoo village area of Yangpyeong County, to collect and analyze basic data of vegetation analysis for indicators development of agro-ecosystem habitat quality. From the observation area, we found total 141 kinds of tracheophytes (53 Family 114 Genus 124 Species 16 Variety 1 Breed) and they are 3.36% of total Korean tracheophytes (4,191 kinds). Among those 141 tracheophytes, there are 23 kinds of naturalized plants (11 Family 20 Genus 20 Species 2 Variety) and they are 8.61% of total Korean naturalized plants (267 kinds). Among those 141 tracheophytes, they include 0.71% of pteridophyte, 0.71% of gymnosperm, 98.58% of angiosperm. So, most of them are angiosperm. When we classify them according to plant life form characteristics, dormant/diapause type plants include 45 species (31.91%) of annual plant (Th), 19 species (13.48%) of Th (w), 17species (12.06%) of hemicryptophyte (H). Regarding propagation type, as for the Radicoid form, there are 99 species (70.21%) of crumb structure plant, 13 species (9.22%) of $R_4$, 12 species (8.51%) of $R_{2.3}$ are the crumb structure does not make any connection on the ground or under ground. As for the Disseminule form of propagation type, there are 62 species (43.97%) of Gravity dispersal type $D_4$), 23 species (16.31%) of Wind dispersal type ($D_1$), 21 species (14.89%) of $D_{1.4}$. According to this survey of plant distribution rate by plant life form characteristics, we may acquire many knowledge about species composition of sociability, cluster's reaction against environmental elements, space usage and possible species competition in community. It may be very useful basic data for habitat preservation to keep and promote biological diversity.