• 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.

• 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 Environmental Agriculture
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• v.38 no.4
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• pp.262-268
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• 2019

BACKGROUND: To investigate mineralization characteristics of organic resources in the soil, five materials (rice straw, cow manure sawdust compost, microorganism compost, mixed oil-cake, and amino acid fertilizer) were treated according to the nitrogen content, and an indoor incubation experiment was conducted for 128 days. The results of this analysis were applied to determine the nitrogen mineralization pattern of these organic resources. METHODS AND RESULTS: During the constant temperature incubation period, the nitrogen net mineralization rate of the organic resources was the highest in the amino acid fertilizer with the highest nitrogen content, and the lowest in the rice straw with the lowest nitrogen content. A positive correlation (0.96) was observed between the potential nitrogen mineralization rate and total nitrogen content. The mineralization rate constant, k, was negatively correlated with the organic matter (-0.96) and carbon content (-0.97). The nitrogen mineralization rate during the first cropping season, as estimated by the model, was 6.6%, 11.6%, 30.9%, 70.7%, and 81.0% for the rice straw, the cow manure sawdust compost, the microorganism compost, the mixed oil-cake, and the amino acid fertilizer, respectively. CONCLUSION: The nitrogen mineralization rate varies depending on the type of organic resources or the nitrogen content; thus, it can be used as an index for determining the nitrogen supply characteristics of the organic resource. Organic resources such as compost with low nitrogen content or those undergoing fermentation contain organic nitrogen. Organic nitrogen is stabilized during the composting process. Therefore, as the nitrogen mineralization rate of these resources is lower than that of non-fermented organic resources, it is desirable to use the fermented organic materials only to improve soil physical properties rather than to supply nutrients for the required amount of fertilizer.

• 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.

• The Korean Journal of Ecology
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• v.18 no.3
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• pp.385-395
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• 1995

Species effects on soil nitrogen mineralization and nitrification in the top 15 cm of soil were evaluated using the buried-bag incubation method in three coniferous plantations in the Kwangneung Experimental Forest, Kyonggi Province. The plantations were established on a similar soil in 1927, and included Larix decidua, Pinus strobus, and Thuja occidentalis. Ten soil samples within each plantation were taken during an entire growing season (May 2~Oct. 30, 1994). Mean daily nitrogen mineralization rates during 45-day in situ soil incubations were significantly different among species and incubation dates. Growing season nitrogen mineralization also differed significantly among species and ranged from 47.7 mg N/kg soil for Larix decidua to 21.5 ma N/kg soil for Thuja occidentalis. Growing season nitrification differed significantly among species and comprised from 93% to 100% of the total growing season nitrogen mineralized. We speculated that organic matter contents and quality might control nitrogen mineralization and nitrification in these soils.

• 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.84 no.2
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• pp.198-206
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• 1995

The objective of this study was to determine the rate of nitrogen mineralization at clearcut and uncut in oak(Quercus rubra L.) and pine(Pinus resinosa Ait.) stands. The study sites were located in northern Lower Michigan, U.S.A. Nitrogen mineralization rates in the top 15cm of mineral soil were examined during the 1991 and 1992 growing seasons(May-October) using an in situ buried tag technique. diet nitrogen mineralization in oak stands over the course of both growing seasons was 67kg/ha in the clearcut and 30kg/ha in the uncut stands. In contrast, net nitrogen mineralization in pine stands was 27kg/ha and 13kg/ha for the same treatments. Total net nitrogen mineralization rates were always higher in oak stands than in pine stands. Extractable $NO_3^-$ before and after one month soil incubation in both oak and pine stands was generally not detectable in the uncut stands, but in the pine clearcut treatment(nitrification over the course of both growing seasons : 3.3kg/ha). The results indicated that : 1) substantial increases in the amount of available soil nitrogen occurred following clearcuts in both stands : and 2) the loin rates of nitrification may be an important mechanism for retention of nitrogen in both oak and pine stands.

• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.119-123
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• 2019

BACKGROUND: Estimation of soil nitrogen supply is essential to manage nitrogen fertilization in arable land. In Korea, nitrogen fertilization is recommended based on the soil organic matter content because it is difficult to assess nitrogen (N) mineralization of upland soils directly. In this study, the relationship between soil organic matter (SOM) content and N mineralization was investigated to explore the limitation of using SOM in predicting soil N mineralization. METHODS AND RESULTS: Soil samples from the 0 to 10 cm depth were collected from 18 individual pepper cultivated fields in Tae-an and Chung-yang provinces before fertilization. N mineralization in the soils was quantified using incubation for 70 days at $30^{\circ}C$. The mineralizable soil N (MSN) was positively correlated with SOM, and the relation equation between MSN and SOM was '$MSN(kg\;10a^{-1})=0.2933{\ast}SOM(g\;kg^{-1})+0.0897$ ($r^2=0.6224$, p<0.001)'. However, the differences of N mineralization among the soils with the similar concentrations of soil organic matter were about 3 to 4.6 times, suggesting that the other soil factors such as total N concentration or EC should affect N mineralization. CONCLUSION: We concluded that SOM alone could not reflect the capacity of soil to supply N that is used for recommendation of N fertilization rate. Therefore, other soil properties should be considered to improve N fertilization management in arable land for sustainable agriculture.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.23-28
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• 1997

A better understanding of nitrogen transformations in soils is essential to increase fertilizer nitrogen use efficiency. A laboratory incubation study was conducted to determine net mineralization and nitrification in selected Piedmont soils. Net mineralization and nitrification increased up to 60 days in the surface layers of Enon, Mecklenburg and Chewacla. After 60 days both processes declined up to 90 days incubation. In Wehadkee, mineralization and nitrification did not differ with incubation time. In all subsurface layers, mineralization and nitrification increased with time up to 90 days. Mineralization and nitrification differed among soils in surface and subsurface layers. These differences might be influenced by soil type related to amount of mineralization, soil aeration and nitrifying bacterial populations. A mineralization and nitrification was greater in surface layers than in subsurface layers.

• The Korean Journal of Ecology
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• v.18 no.4
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• pp.493-502
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• 1995

Nodulation phenology in relation to plant phenology, vertical distribution of nodul and root biomass in different soil, correlation between nodule and root size, and nitrogen mineralization around the rhizosphere by ion-exchange resin bag buried at 10 cm of soil were studied in Elaeagnus nmbellata (autumn-olive) stand, Korea. Nodulation appeared from spring to autumn and nodule phenology was coincided with the timing of root activity rather than that of foliation. Nodul size increased in proportion to the root size. In the sand dune with the lower root biomass, nodule appeared up to 80 cm deep in soil and the nodule biomass was 1,070 kg/ha, which was the highest value reported for several actinorhizal plants in the temperate regions. It is suggested that nodule distribution and production are mainly influenced by soil aeration among environmental factors. The higher ammonification or lower nitrification rate contrasted markedly with the earlier studies that reported lower ammonification or higher nitrification in actinorhizal plant soil. Nitrogen mineralization rate around the rhizosphere with root and nodule was characterized by higher nitrification rate than that in the control soil without root and nodule.