• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.102-105
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• 1999

Mineralization of organic N is an important factor in determining the appropriate rate of organic matter application to paddy fields. A kinetic analysis was conducted for nitrogen mineralization of rice, barley, Chinese milk Ovetch (Astragalus sinicus L.; MV) and narrow leaf vetch straw in paddy soil. Nitrogen immobilization occurred rapidly and its rate increased in straw with high C/N ratio. The amount of nitrogen mineralization was rapid in the first year of rice-vetch cropping system. The rate constant (K) depended on the C/N ratio of organic matter. Mineralization of straw increased at high temperature. The amount of available N increment resulted in fast mineralization of straw, especially in rice and barley straw. Chinese milk vetch had the greatest mineralization rate at all temperatures and fertilization levels followed by narrow-leaf vetch. However, rice and barley straws with high C/N ratio immobilized the soil N at the initial incubation duration. Chinese milk vetch or narrow leaf vetch was not effectively mineralized in mixed treatments with rice or barley straw. The mineralization rate of organic matter was mostly affected by the C/N ratio of straw and temperature of incubation. Organic matter with low C/N ratio should be recommended to avoid the immobilization of soil N and the increasing mineralization rate of straw.

• Korean Journal of Veterinary Research
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• v.59 no.4
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• pp.223-226
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• 2019

A 7-year-old, spayed female Chihuahua with dyspnea, intermittent cyanosis, and dermal plaques was diagnosed with hyperadrenocorticism. Thoracic radiographs showed markedly hyperdense alveoli in multiple lung lobes. Computed tomography (CT) images showed lung mineralization confined to the lung parenchyma and pituitary macroadenoma. Pulmonary mineralization secondary to hyperadrenocorticism is commonly found on histopathologic examination. However, those lesions are rarely identified radiographically. We describe obvious pulmonary mineralization secondary to hyperadrenocorticism found on radiographs and present the first report regarding CT imaging of the mineralization. Pulmonary mineralization should be considered when a dog affected by hyperadrenocorticism shows diffuse lung mineralization on radiographs.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.751-760
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• 2015

Management of renewable organic resources is important in attaining the sustainability of agricultural production. However, nutrient management with organic resources is more complex than fertilization with chemical fertilizer because the composition of the organic input or the environmental condition will influence organic matter decomposition and nutrient release. One of the most effective methods for estimating nutrient release from organic amendment is the use of N mineralization models. The present study aimed at parameterizing N mineralization models for a number of organic amendments being used as a nutrient source for crop production. Laboratory incubation experiment was conducted in aerobic condition. N mineralization was investigated for nineteen organic amendments in sandy soil and clay soil at $20^{\circ}C$, $25^{\circ}C$, and $30^{\circ}C$. N mineralization was facilitated at higher temperature condition. Negative correlation was observed between mineralized N and C:N ratio of organic amendments. N mineralization process was slower in clay soil than in sandy soil and this was mainly due to the delayed nitrification. The single and the double exponential models were used to estimate N mineralization of the organic amendments. N mineralization potential $N_p$ and mineralization rate k were estimated in different temperature and soil conditions. Estimated $N_p$ ranged from 28.8 to 228.1 and k from 0.0066 to 0.6932. The double exponential model showed better prediction of N mineralization compared with the single exponential model, particularly for organic amendments with high C:N ratio. It is expected that the model parameters estimated based on the incubation experiment could be used to design nutrient management planning in environment-friendly agriculture.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.178-179
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• 2003

Mesothermal, tellurium-bearing gold-silver vein mineralization of the Yuryang mine was formed in mineralogically complex quartz-sulfide veins that filled the fault fractures in Precambrian gneiss within Gyeonggi Massif. Ore grades average 179 g/ton gold with a gold/silver ratio of 1.5 : 1. Ore mineralization was deposited in single stage. Major ore mineralization can be divided into two mineralization phases with increasing paragenetic time: Fe-sulfide and base-metal mineralization phase $\rightarrow$ telluride mineralization phase. (omitted)

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.712-719
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• 2016

Understanding N mineralization dynamics in soil is essential for efficient nutrient management. An anaerobic incubation experiment was conducted to examine N mineralization potential and N mineralization rate of the organic amendments with different C:N ratio in paddy soil. Inorganic N in the soil sample was measured periodically under three temperature conditions ($20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$) for 90 days. N mineralization was accelerated as the temperature rises by approximately $10%^{\circ}C^{-1}$ in average. Negative correlation ($R^2=0.707$) was observed between soil inorganic N and C:N ratio, while total organic carbon extract ($R^2=0.947$) and microbial biomass C ($R^2=0.824$) in the soil were positively related to C:N ratio. Single exponential model was applied for quantitative evaluation of N mineralization process. Model parameter for N mineralization rate, k, increased in proportion to temperature. N mineralization potential, $N_p$, was very different depending on C:N ratio of organic input. $N_p$ value decreased as C:N ratio increased, ranged from $74.3mg\;kg^{-1}$ in a low C:N ratio (12.0 in hairy vetch) to $15.1mg\;kg^{-1}$ in a high C:N ratio (78.2 in rice straw). This result indicated that the amount of inorganic N available for crop uptake can be predicted by temperature and C:N ratio of organic amendment. Consequently, it is suggested that the amount of organic fertilizer application in paddy soil would be determined based on temperature observations and C:N ratio, which represent the decomposition characteristics of organic amendments.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.559-564
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• 2011

Soil microbial functions are considered to be effective in assessing the severity of heavy metal pollution. Therefore, this study was carried out to examine the effect of heavy metals on nitrogen mineralization by measuring the releasing pattern of inorganic nitrogen ($NH_4^+$-N and $NO_3^-$-N) in a soil treated with heavy metals. A factorial combination of two heavy metals (Zn and Cd) treated with three concentrations (50, 100 and $150{\mu}mol\;g^{-1}$ soils) was used in a laboratory incubation. Nitrogen mineralization was determined at 3, 7, 14, 21, 28, 42 and 56 days after the treatments replicated four times. Soil sample free from heavy metals was served as the control. The amount of nitrogen mineralization from heavy metal treated soils was found to be decreased at an increasing rate during the first 21 days of incubation. However, as the incubation progressed, nitrogen mineralization was found to be decreased at decreasing rates. Furthermore, during this period, nitrogen mineralization in Cd treated soils was significantly lower ($P{\leq}0.05$) than that of the control. Soils treated with Cd at the concentration of $150{\mu}mol\;g^{-1}$ showed the lowest N mineralization throughout the incubation. Nitrogen mineralization in Zn treated soils ($50{\mu}mol\;g^{-1}$) was found to be higher than the other heavy metal treated soils. On the base of present findings, nitrogen mineralization of soil could be considered as a viable assessment of the degree of heavy metal pollution.

• The Korean Journal of Ecology
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• v.21 no.6
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• pp.751-757
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• 1998

Nitrogen dynamics in mineral soils of an alder (Alnus maximowiczii) stand established on volcano Mt. Showa-Shinzan were measured by laboratory incubation method in order to clarify characteristics of $NH_{4}^{+}$ mineralization and nitrification rate, from August 1994 to July 196. Contents of total N and organic matter were relatively low, but increased in May-July. Extractable $NH_{4}^{+}$ concentrations and $NH_{4}^{+}$ mineralization were high in June and July, and decreased in midsummer and fall. Extractable $NO_{3}^{-}$ concentrations did not vary seasonally. Negative values at $NH_{4}^{+}$ mineralization and nitrification rate were observed in August and September. $NH_{4}^{+}$ mineralization was positively correlated with soil organic matter, and nitrification rates were influenced by extractable $NH_{4}^{+}$ concentration and $NH_{4}^{+}$ mineralization.

• The Korean Journal of Ecology
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• v.18 no.2
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• pp.219-230
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• 1995

Although many studies of nutrient cycling in forest ecosystems have reported that clearcutting creates increased organic matter decomposition and nitrogen (N) mineralization in soils, little is known about the change of these factors following various levels of canopy removal. A series of experimental plots with four levels of canopy cover, i.e., clearcut, 25％, 75％, and uncut, was established in northern red oak (Quercus rubra L.) stands in northern Lover Michigan, U.S.A. I examined decomposition of cellulose filter papers and N mineralization using an in situ soil incubation technique in the top 15cm of mineral soil during the second growing season (1992, May-October) following stand manipulation. Mass loss from cellulose filter papers was more rapid in the canopy removal treatments than in the uncut treatment. similarly, net N mineralization was significantly greater in the canopy removal treatments than in the uncut treatment. There was no significant difference in net N mineralization rates among the three levels of canopy removal. Net N mineralization for the growing season was 58 kg/ha for the clearcut, 54 kg/ha for the 25％ canopy cover, 51 kg/ha for the 75％ canopy cover, and 22 kg/ha for the uncut treatment. These results indicated that even only small amounts of canopy removal (leaving 75％ canopy cover) let to substantial increases of cellulose decomposition and the amount of available soil nitrogen.

• Journal of Korean Society of Forest Science
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• v.87 no.1
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• pp.20-26
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• 1998

The objective of this study was to determine the rate of nitrogen mineralization and nitrification in a mature sawtooth oak(Quercus acutissima $C_{ARRUTH}$) stand in the Chungbu Forest Experiment Station, Kyonggi Province. Nitrogen mineralization and nitrification in the top 15cm of mineral soil were examined from November 1995 to November 1996 using an in situ buried bag method. Net nitrogen mineralization was 95.2mg/kg/yr and nitrification was 65.4mg/kg/yr. Nitrification consisted of 69% of annual nitrogen mineralization. Neither nitrogen mineralization nor nitrification was significantly correlated with the monthly soil temperature and soil moisture content.

• Economic and Environmental Geology
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• v.10 no.2
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• pp.67-74
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• 1977

Biggest talc deposits of South Korea, localized in Choong-Chung-Nam-do, are known as a products of hydrothermal metamorphism of serpentine. From studying mineral paragenesis and localization, three types of talc mineralization is presumed as follows: 1) Extended talc mineralization from autometamorphism (serpentinization) of ultra-basic igneous rocks, 2) Schistose talc rock as green schist facies of regional metamorphism and 3) Late hydrothermal mineralization and purification of serpentine and pre-existing low grade ores.