• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.467-474
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• 2012

This study was carried out to evaluate effect of temperature condition on nitrogen mineralization of organic matter, distribution of microbial group by PLFA profiles, and soil microbial community structure in volcanic ash soil. Dried soil 30 g mixed well each 2 g of pellet (OFPE) organic fertilizers, pig manure compost (PMC), and food waste compost (FWC). And then had incubated at $10^{\circ}C$, $20^{\circ}C$, and $30^{\circ}C$, respectively. Nitrogen mineralization rate increased with increasing temperature and that was in the order of FWC>OFPE>PMC. Distribution ratio of microbial group by PLFA profiles were different significantly caused by incubation temperature and the type of organic matter. As incubating time passed, density of microbial group decreased gradually. The Gram-bacteria PLFA/Gram+ bacteria PLFA, Fungi PLFA/Bacteria PLFA, and Unsaturated PLFA/saturated PLFA ratios were decreased according to the increasing temperature gradually. But cy19:0/$18:1{\omega}7c$ ratio increased both FWC and PMC treatment. Principal component analysis using PLFA profiles showed that microbial community structure made up clearly at both 75 days ($10^{\circ}C$) and 270 days ($30^{\circ}C$) by temperature factor. As incubating time passed, microbial community structure shifted gradually.

• Journal of Ecology and Environment
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• v.40 no.1
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• pp.5-11
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• 2016

Background: As the decomposition of lignocellulosic compounds is a rate-limiting stage in the nutrient mineralization from organic matters, elucidation of the changes in soil enzyme activity can provide insight into the nutrient dynamics and ecosystem functioning. The current study aimed to assess the effect of thinning intensities on soil conditions. Un-thinned control, 20 % thinning, and 30 % thinning treatments were applied to a Larix kaempferi forest, and total carbon and nitrogen, total carbon to total nitrogen ratio, extractable nutrients (inorganic nitrogen, phosphorus, calcium, magnesium, potassium), and enzyme activities (acid phosphatase, ${\beta}$-glucosidase, ${\beta}$-xylosidase, ${\beta}$-glucosaminidase) were investigated. Results: Total carbon and nitrogen concentrations were significantly increased in the 30 % thinning treatment, whereas both the 20 and 30 % thinning treatments did not change total carbon to total nitrogen ratio. Inorganic nitrogen and extractable calcium and magnesium concentrations were significantly increased in the 20 % thinning treatment; however, no significant changes were found for extractable phosphorus and potassium concentrations either in the 20 or the 30 % thinning treatment. However, the applied thinning intensities had no significant influences on acid phosphatase, ${\beta}$-glucosidase, ${\beta}$-xylosidase, and ${\beta}$-glucosaminidase activities. Conclusions: These results indicated that thinning can elevate soil organic matter quantity and nutrient availability, and different thinning intensities may affect extractable soil nutrients inconsistently. The results also demonstrated that such inconsistent patterns in extractable nutrient concentrations after thinning might not be fully explained by the shifts in the enzyme-mediated nutrient mineralization.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.210-224
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• 2003

Sulfate reduction is a microbiological process which occurs ubiquitously in anaerobic marine environment. Sulfate reducing bacteria play a significant role in anaerobic decomposition of organic matter and regeneration of inorganic nutrients which supports the primary production in the water column (i.e., benthic-pelagic coupling) and, in special case, could be responsible for the harmful algal bloom in the coastal marine environment. Summary of the sulfate reduction rates reported in various marine sedimentary environments revealed that supply of organic substrates and presence of various electron acceptors (i.e., $O_2$, NO$_{3}$$^{[-10]}$ , Fe(III) and Mn(IV), etc.) for other aerobic and anaerobic respiration directly affect the sulfate reduction rate and relative significance of sulfate reduction in organic matter mineralization. Significance of temperature, macrophytes and bioturbation is discussed as factors controlling supply of organic substrates and distribution of electron acceptors. Finally, we suggest studies on the anaerobic microbiological processes associated with biogeochemical element cycles in the coastal environments of Korea where massive operation of organic enriched fish cage farm, frequent occurrence of toxic algal bloom and hypoxia and conservation of tidal flat are of major environmental issues.

• Journal of Environmental Science International
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• v.20 no.7
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• pp.919-927
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• 2011

A ecosystem model was applied for understanding of circulation process of state variables in marine ecosystem. A mass balance was conducted by calculating the physical process. The sensitivity analysis was conducted to know which coefficient is the most effective factor to the state variables in the model. The results of the mass balance indicate that the primary production was 58.6 ton C/day in the case of mass flux. DIN and DIP in nutrient ingestion of phytoplankton were each 7.9 ton N/day, 1.1 ton P/day. POC and DOC in mineralization of organic matter were each 10.8 ton C/day, 40.6 ton C/day. The results of sensitivity analysis showed that the maximum growth rate of phytoplankton was the most important factor for overall state variables. In the case of nutrients, Half saturation constant of DIN, and mineralization rate of DOM for COD were important factor.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.805-819
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• 2017

The study was carried out to develop a mathematical model for evaluating the effect of organic fertilizers in organic rice production systems. A function to simulate the nitrogen mineralization process in the paddy soil has been developed and integrated into ORYZA2000 crop growth model. Inorganic nitrogen in the soil was estimated by single exponential models, given temperature and C:N ratio of organic amendments. Data collected from the two-year field experiment were used to evaluate the performance of the model. The revised version of ORYZA2000 provided reasonable estimates of key variables for nitrogen dynamics and crop growth in the organic rice production systems. Coefficient of determination between the measured value and simulated value were 0.6613, 0.8938, and 0.8092, respectively for soil inorganic nitrogen, total dry matter production, and rice yield. This means that the model could be used to quantify nitrogen supplying capacity of organic fertilizers relative to chemical fertilizer. Nitrogen dynamics and rice growth simulated by the model would be useful information to make decision for organic fertilization in organic rice production systems.

• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.59-70
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• 2012

This experiments was conducted to investigate the influence on the growth of Sorghum ${\times}$ Sudangrass hybrid by use of various organic fertilizer and investigated their productivity, feed value and stock carrying capacity. In the results, the application of fermented poultry manure showed 93.6ton/ha, 19.6ton/ha, 1.12ton/ha, 11.31ton/ha of fresh yield, dry matter yield, crude protein (CP) yield and total digestible nutrients (TDN) yield but there were no significant differences with the application of poultry by-product compost (poultry manure with sawdust) and swine by-product compost (swine manure with sawdust). And the average value of $K_{CP}$ and $K_{TDN}$ showed the highest one as 9.45head/ha/yr in the application of fermented poultry manure. However, organic matter content of fermented poultry manure to the lower portion of 32.1% compared to other organic fertilizers could imagine that mineralization of fermented poultry manure was fairly advanced and plant used most of nitrogen in fermented poultry manure, so productivity of Sorghum ${\times}$ Sudangrass hybrid was shown more than other organic fertilizers. If other organic fertilizers use continuous, this difference can be considered to be reduced further. As a result, fermented poultry manure is better than other organic fertilizers in productivity, feed value and stock carrying capacity due to the higher content of mineralizable matters. In addition, mixing poultry manure with cow and swine manure is better choice because cow and swine manure will meet a low organic matter in poultry manure.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.329-334
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• 2010

The characteristics of nitrogen mineralization in upland soil was studied with 27-week incubation at $25^{\circ}C$. The used soils in this experiment were received six kinds of livestock manure compost each year for four years. Six different composts, which were chicken (CHM), pig (PIM), and cow (COM) manure composted without bulking agent, and chicken (CHMS), pig (PIMS), and cow (COMS) manure composted with sawdust as a bulking agent, were selected for this study. The first-order model was fit to the observed mineral nitrogen (N) vs incubation days using a non-linear regression procedure. The soil potential for N mineralization (No) of manure compost (CHM, PIM, and COM) treated soils were higher than those of the manure-sawdust compost (CHMS, PIMS, and COMS) treated soils. The No value of PIM applied soil was 15.0 mg 100 $g^{-1}$, which was the highest value among the treatments. The amount of N mineralized in compost applied soils ranged from 8.1% to 11.9% of the total N content in soils and increased with increasing total N content in soils. The organic matter content in compost applied soils were negatively correlated with No value (r = $-0.69^*$). Therefore, our result indicated that determination of N application rate in livestock manure compost applied soil should be based on total nitrogen content better than soil organic matter content.

• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.124-132
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• 2019

BACKGROUND: Silver grass (Miscanthus sinensis) No. 1 was developed for production of bio-ethanol, and for the purpose the silver grass growing sector was established in Geumgang basin, Iksan, Jeonbuk, in 2011. However, the other application potentials except for using as the bio-energy resources should be considered because of the drop in international oil prices. Therefore, there is the necessity of a scientific basis to use the silver grass instead of rice straw as the organic matter source that is used for improvement of soil quality in the plastic film house. METHODS AND RESULTS: The silver grass was applied at 5, 10, 15 and 20 Mg/ha and tilled before the watermelon was planted in the plastic film-house. The control plot was treated with 10 Mg/ha with rice straw, and watermelons have been cultivated for 3 years(2017~2019). Soil aggregation, soil chemistry, and the growth characteristics were investigated, when the watermelon was harvested every year. Soil aggregation levels at the 2nd and 3rd year of watermelon harvest were similar from the plot applied with the silver grass at 5 Mg/ha and the control plot, and increased in the silver grass treated plots with more than 10 Mg/ha. However, there was no statistically significant difference between the plots. The nitrogen mineralization of silver grass in the control plot tended to be similar to the 5 Mg/ha plot, but the silver grass treated plots with over 10 Mg/ha showed low nitrogen mineralization. Soil EC on harvest stage was proportional to the applied mass of the silver grass, but pH was in inverse with the applied mass. Soil organic matter content, available phosphate, and exchangeable cations increased with the continued use of silver grass. Watermelon weight found to be the best on more than 15 Mg/ha of silver grass, and the sugar content was highest when 10 Mg/ha was treated. CONCLUSION: The use of the silver grass at 10 Mg/ha annually as the organic source was effective in replacing rice straw while growing fruits and vegetables on the plastic film house.

• Applied Biological Chemistry
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• v.27
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• pp.56-67
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• 1984

As in many other country, the use of organic matter in Korea has long history. Farmers understand the value of organic matter as the source of plant nutrient and soil improving agent in general. Since 50 years ago, the sources of organic matter in paddy soils were compost, rice and barly straw, green manure, animal waste, fish and beancake, etc.. Application of green manures such as vetch and chinese milk vetch showed no significant effect on the yield of brown rice in paddy soil. On the other hand, the effects of compost and rice straw showed more significant on the yield of brown rice in paddy soil. Application of rice straw in rice cultivation is commonly made at different times between harvest, early spring and several weeks before transplanting. Considering the suitable paddy soil for application of rice straw under well to moderately well drained soil, the yield was pronounced more than poorly drained soil. Based on laboratory and field experimants, application of rice straw promoted the decrease of oxidation-reduction potential in well to moderately well drained soil. This results to be enhanced the release of some mineral nutrients,. such as potassium, calcium, silicon, and increase of availability of soil phosphorus. In the field experiments, results obtained from nitrogen fraction on the immobilization-mineralization of the tracer nitrogen applied in paddy soil,the amount and index of organic nitrogen incoporated in soil was more pronounced in rice straw application than control. Rice straw and its transformation products incoporated in the soil, provided the inflow of energy necessary to maintain heterotrophic microbes activities. Rice straw and its transformation products, especially soluble carbohydrate, enhanced the population of free-living heterotrophic $N_2$ - fixing microbes. Moreover, rice straw and its transformation products in paddy soil, enhanced the activities of soil enzymes such as dehydrogenase and urease.

• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.81-89
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• 2012

This study was investigated to evaluate the effects of fertilizer application of surface and broadcast for rice culture on the soil chemical, physical, and microbial properties as well as growth and yield of rice. The application was made with 'Dongjin 1' rice at Jeollanam-do Agricultural Research & Extension Services from 2008 to 2010. Soil organic matter and cation concentrations were increased by surface and broadcast applications, respectively. Plots treated by surface application tended to be higher seasonal N-mineralization rate in the organic fertilizer and seasonal soil organic matter than those of broadcast application. Soil physical properties seemed to be improved by the broadcast application, and soil microbial properties were increased by the surface application. Surface application increased 5% of rice yield compared to that of broadcast.