• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.413-420
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• 2015

Objective of this study was to investigate adsorption characteristics and kinetic models of $NH_4-N$ to biochar produced from rice hull in respective to mitigation of greenhouse gases. $NH_4-N$ concentration was analyzed by UV Spectrophotometer. For the experiment, the soil texture used in this study was sandy loam soil, and application rates of chemical fertilizer and pig compost were $420-200-370kgha^{-1}$ (N-P-K) and $5,500kgha^{-1}$ as recommended amount after soil test for corn cultivation. Biochar treatments were 0.2-5% to soil weight. Its adsorption characteristic was investigated with application of Langmuir isotherm, and pseudo-first order kinetic model and pseudo-second order kinetic model were used as kinetic models. Adsorption amount and removal rates of $NH_4-N$ were $39.3mg^{-1}$ and 28.0% in 0.2% biochar treatment, respectively. The sorption of $NH_4-N$ to biochar was fitted well by Langmiur model because it was observed that dimensionless constant ($R_L$) was 0.48. The maximum adsorption amount ($q_m$) and binding strength constant (b) were calculated as $4.1mgg^{-1}$ and $0.01Lmg^{-1}$ in Langmuir isotherm, respectively. The pseudo-second order kinetic model was more appropriate than pseudo-first order kinetic model for high correlation coefficient ($r^2$) of pseudo-second order kinetic model. Therefore, biochar produced from rice hull could reduce $N_2O$ by adsorbing $NH_4-N$ to biochar cooperated in sandy loam soil.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.623-640
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• 2013

Soil organic carbon (SOC) of soil series is necessary to calculate soil C sequestration due to IPCC default categorized by climate regions and by soil types. The 3,400 thousand data were downloaded from agricultural soil information system and analyzed to get averages of soil order, soil series, and textual family for the three different soil management practices in Korea. The SOC content was $13.3{\pm}5.38g\;kg^{-1}$ in paddy field, $13.7{\pm}7.19g\;kg^{-1}$ in upland field, and $15.2{\pm}8.22g\;kg^{-1}$ in orchard soil, respectively. As SOC in orchard was 10% greater than that in upland, orchard must be managed with applying compost. The SOCs of inceptisols, which was largely distributed in Korea, were $13.6{\pm}5.48g\;kg^{-1}$ in paddy field, $14.1{\pm}7.38g\;kg^{-1}$ in upland field, and $15.3{\pm}8.20g\;kg^{-1}$ in orchard soil, respectively. The SOCs of alfisols were $13.6{\pm}4.96g\;kg^{-1}$ in paddy field, $13.7{\pm}6.99g\;kg^{-1}$ in upland field, and $15.6{\pm}8.59g\;kg^{-1}$ in orchard soil, respectively. The SOCs of entisols were $11.7{\pm}5.16g\;kg^{-1}$ in paddy field, $12.8{\pm}7.05g\;kg^{-1}$ in upland field, and $13.7{\pm}7.81g\;kg^{-1}$ in orchard soil, respectively. The SOCs of ultisols were $12.7{\pm}4.79g\;kg^{-1}$ in paddy field, $12.7{\pm}6.22g\;kg^{-1}$ in upland field, and $16.3{\pm}8.49g\;kg^{-1}$ in orchard soil, respectively. The fact that soils containing greater clay content in textual family had also more SOC content revealed that SOC could be also dependent on some soil properties as well as soil order. Because SOC differences among soil series representing same textual family were greater than those among textual family, SOC differences should be mainly affected by management practices such as compost application.

• Journal of Ginseng Research
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• v.6 no.2
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• pp.168-203
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• 1982

Effects of soil moisture on growth of Panax ginseng, of various factors on soil moisture, and of moisture on nutrition, quality, physiological disorder, diseases and insect damage were reviewed. Optimum soil moisture was 32% of field capacity with sand during seed dehiscence, and 55-65% for plant growth in the fields. Optimum soil moisture content for growth was higher for aerial part than for root and higher for width than for length. Soil factors for high yield in ginseng fields appeared to be organic matter, silt, clay, agreggation, and porosity that contributed more to water holding capacity than rain fall did, and to drainage. Most practices for field preparation aimed to control soil moisture rather than nutrients and pathogens. Light intensity was a primary factor affecting soil moisture content through evaporation. Straw mulching was best for the increase of soil moisture especially in rear side of bed. Translocation to aerial part was inhibited by water stress in order of Mg, p, Ca, N an Mn while accelerated in order of Fe, Zn and K. Most physiological disorders(leaf yellowing, early leaf fall, papery leaf spot, root reddening, root scab, root cracking, root dormancy) and quality factors were mainly related to water stress. Most critical diseases were due to stress, excess and variation of soil water, and heavy rain fall. The role of water should be studied in multidiciplinary, especially in physiology and pathology.

• Journal of Environmental Science International
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• v.16 no.6
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• pp.725-733
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• 2007

The contents of five heavy metals such as lead, cadmium, zinc, copper and manganese in soil and vegetables collected from four sites in Busan district with composite sampling method were determined with ICP emission spectrometer. The ranges of their contents in soil were lead, $1.65\sim4.36ppm;$ cadmium, $0.05\sim0.09ppm;$ zinc, $6.33\sim11.09ppm;$ copper, $0.44\sim1.35ppm;$ manganese, $8.40\sim19.39ppm$, respectively. These contents were lower than the Clarke number. The range of heavy metal contents in four vegetables such as lettuce, radish and its roots, spinach and cabbage were lead, $0.09\sim0.48ppm;$ cadmium, $0.01\sim0.08ppm;$ zinc, $1.81\sim14.62ppm;$ copper, $0.14\sim1.87ppm;$ manganese, $0.71\sim14.5$ 5ppm with the order of Zn(7.30 ppm)>Mn(4.35 ppm)>Cu(0.53 ppm)>Pb(0.19 ppm)>Cd(0.04 ppm) in average contents. The average transfer ratio of metals from soil to vegetables was order of Zn(77.8 %)> Cd(37.5 %)>Cu(34.5 %)>Mn(18.6 %)>Pb(6.7 %). In case of the same cultivating soil, the transfer ratio could be expected to the order of spinach$lettuce{\approx}cabbage$

• Korean Journal of Microbiology
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• v.21 no.1
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• pp.7-14
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• 1983

In order to study the effects of cropping system and fungicide (Dachigaren) on soil microbes, the seasonal fluctuations of soil microbes in the fields of radish and Chinese cabbage including soil pH, Soil moisture content and soil temperature were investigated on every 15 day interval from the begining of March to late October in 1981. The population of total fungus peaked at the begining of July, while that of total bacteria, at the begining of August. They were affected by soil temperature, however pathogenic microbes seemed to be more related with host plants than the soil temperature, because pathogens showed high density through the whole cultivation period. The pathogenic microbes showed the density of order ; Xanthomonas, Erwinia, Pseudomonas, Agrobacterium and Corynebacterium. Xanthomonas, Erwinia and Pseudomonas, which induced radish and Chinese cabbage diseases were higher than Agrobacterium and Corynebacterium in population densigy. Bacterial soft rot occured at the density of Erwinia $5.9{\sim}6.6{\times}10^5/dry$ soil 1 gram. The density of microbes on continuous fields were higher than that of rotating fields, but there were no significant difference between treated fungicide plot and non treated in the density of microbes, also no difference between Chinese cabbage and radish growing fields.

• Journal of the Korean Society of Clothing and Textiles
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• v.6 no.2
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• pp.33-40
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• 1982

The removal and redeposition of particulate soil occur simultaneously during the washing process. In order to investigate variables which affect on the redeposition of particulate soil, cotton lawn was soiled in the ion oxide black suspension using Launder-O meter. The amount of deposited soil was estimated by means of the spectrometric analysis of iron on the fabric after soiled. The results are as follows: 1. The presence of surfactants b suspension decreased the deposition of particulate soil and the most effective surfactant was soap and the descending order was NaDBS>CTAB>PONPE. 2. The influnce of temperature on soil deposition was considerable, soil deposition was gradually increased with elevating temperature in ionic surfactants solution such as NaDBS and CTAB but that was decreased above $40^{\circ}C$ in nonionic surfactant solution. 3. The tendency of soil deposition was dwindled by adding electrolytes especially in case of polyvalent anions. 4. From the results of the experiments redeposition of particulate soil was related with suspending power of surfactants and was influenced by factors varing zeta potential.

• Geomechanics and Engineering
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• v.34 no.6
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• pp.597-609
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• 2023

One of the applicable methods for the stabilization of soil walls is the nailing system which consists of tensile struts. The stability and safety of soil nail wall systems are influenced by the geometrical parameters of the nailing system. Generally, the determination of nailing parameters in order to achieve optimal performance of the nailing system for the safety of soil walls is defined in the framework of optimization problems. Also, according to the various uncertainty in the mechanical parameters of soil structures, it is necessary to evaluate the reliability of the system as a probabilistic problem. In this paper, the optimal design of the nailing system is carried out in deterministic and probabilistic cases using meta-heuristic and reliability-based design optimization methods. The colliding body optimization algorithm and first-order reliability method are used for optimization and reliability analysis problems, respectively. The objective function is defined based on the total cost of nails and safety factors and reliability index are selected as constraints. The mechanical properties of the nailing system are selected as design variables and the mechanical properties of the soil are selected as random variables. The results show that the reliability of the optimally designed soil nail system is very sensitive to uncertainty in soil mechanical parameters. Also, the design results are affected by uncertainties in soil mechanical parameters due to the values of safety factors. Reliability-based design optimization results show that a nailing system can be designed for the expected level of reliability and failure probability.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.4
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• pp.260-266
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• 2008

Small lysimeter experiment under rain shelter plastic film house was conducted to investigate the effect of soil characteristics on the leaching and soil solution concentration of nitrate and phosphate. Three soils were obtained from different agricultural sites of Korea: Soil A (mesic family of Typic Dystrudepts), Soil B (mixed, mesic family of Typic Udifluvents), and Soil C (artificially disturbed soils under greenhouse). Organic-C contents were in the order of Soil C ($32.4g\;kg^{-1}$) > Soil B ($15.0g\;kg^{-1}$) > Soil A ($8.1g\;kg^{-1}$). Inorganic-N concentration also differed significantly among soils, decreasing in the order of Soil B > Soil C > Soil A. Degree of P saturation (DPS) of Soil C was 178%, about three and fifteen times of Soil B (38%) and Soil A (6%). Prior to treatment, soils in lysimeters (dia. 300 mm, soil length 450 mm) were tabilized by repeated drying and wetting procedures for two weeks. After urea at $150kg\;N\;ha^{-1}$ and $KH_2PO_4$ at $100kg\;P_2O_5\;ha^{-1}$ were applied on the surface of each soil, total volume of irrigation was 213 mm at seven occasions for 65 days. At 13, 25, 35, 37, and 65 days after treatment, soil solution was sampled using rhizosampler at 10, 20, and 30 cm depth and leachate was sampled by free drain out of lysimeter. The volume of leachate was the highest in Soil C, and followed by the order of Soils A and B, whereas the amount of leached nitrate had a reverse trend, i.e. Soil B > Soil A > Soil C. Soil A and B had a significant increase of the nitrate concentration of soil solution at depth of 10 cm after urea-N treatment, but Soil C did not. High nitrate mobility of Soil B, compared to other soils, is presumably due to relatively high clay content, which could induce high extraction of nitrate of soil matrix by anion exclusion effect and slow rate of water flow. Contrary to Soil B, high organic matter content of Soil C could be responsible for its low mobility of nitrate, inducing preferential flow by water-repellency and rapid immobilization of nitrate by a microbial community. Leached phosphate was detected in Soil C only, and continuously increased with increasing amount of leachate. The phosphate concentration of soil solution in Soil B was much lower than in Soil C, and Soil A was below detection limit ($0.01mg\;L^{-1}$), overall similar to the order of degree of P saturation of soils. Phosphate mobility, therefore, could be largely influenced by degree of P saturation of soils but connect with apparent leaching loss only more than any threshold of P accumulation.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.147-152
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• 2001

This study investigated one-dimensional vertical infiltration to an unsaturated residual soil by numerical solutions, FDM. In order to estimate the parameters needed for numerical analysis, tire soil-water characteristic curve(SWCC) of Shinnae-dong soil, one of the most typical residual soils in Korea, were experimentally obtained. Then, the statistical analysis for obtaining the SWCC was performed. The numerical solution to the linearized governing equation for unsaturated groundwater flow provides the infiltration characteristics for the unsaturated residual soil represented by transient pressure profiles and water contents profiles.

• Magazine of the Korean Society of Agricultural Engineers
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• v.26 no.2
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• pp.47-58
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• 1984

The study results of the mosture consumption character and irrigation effect of tomato, red pepper and chinese cabbage, in case the soil moisture is kept with different moisture content by the soil properties(loam, sandy loam, sand), are summarized as follows: 1. The available rainfall under bare soil condition had an order of sand>sandy loam> loam and their average was 64.2%. 2. Total moisture consumption under bare soil condition had an order of loam>sandy loam>sand and their average was 4.2mm. 3. The amount of irrigated water to keep certain soil moisture under bare soil condition showed minimum in sand and maximum in loam. It is considered because the capillary phenomenon was more developed in loam. 4. Total moisture consumption of tomatoes under premature cultivation showed 925mm in maximum and had on order of loam>sandy loam>sand. In the aspect of re-irrigation point, it had an order of PF 1.5> PF 1.7>PF 2.1. In case the twenty years's drought frequency was taken into account, the target amount of irrigation water meeded for premature cultivation was 916mm and its average daily moisture consumption was 10.8mm. 5. Total moisture consumption of red pepper under open cultivation showed 1145mm in maximum and had an order of loam>Sandy loam>sand. In the aspect of re-irrigation frequency was taken into consideration the target amount of irrigation water was 1,174.8mm and its average daily moisture consumption was 8.0mm. 6. Total moisture consumption of autumn chinese cabbages was 349mm in maximum and had an order of loam>sandy loam>sand. In the aspect of re-irrigation point, it had an order of PF 1.5>PF 2.1>PF 2.7. In case the twenty year's drought frequency was taken into account, the target amount of irrigation water needed for chinese cabbage cultivation was 259.5mm and its average daily moisture consumption was 6.5mm. 7. It is effective to keep the soil moisture of tomato from PF 1.5 to PF 2.1 in loam and the soil moisture control was effective in sandy loam than red pepper and chinese cabbage. In sand, the production was severaly decreased and the re-irrigation point of PF 1.5 was effective.