• Environmental Engineering Research
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• v.22 no.4
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• pp.347-355
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• 2017

This study investigated how the combined changes in environmental conditions and nitrogen (N) deposition influence the mineralization processes and carbon (C) dynamics of wetland soil. For this objective, we conducted a growth chamber experiment to examine the effects of combined changes in environmental conditions and N deposition on the anaerobic decomposition of organic carbon and the emission of greenhouse gases from wetland soil. A chamber with elevated $CO_2$ and temperature showed almost twice the reduction of total decomposition rate compared to the chamber with ambient atmospheric conditions. In addition, $CO_2$ fluxes decreased during the incubation under the conditions of ambient $CO_2$ and temperature. The decrease in anaerobic microbial metabolism resulted from the presence of vegetation, which influences the litter quality of soils. This can be supported by the increase in C/N ratio over the experimental duration. Principle component analysis results demonstrated the opposite locations of loadings for the cases at the initial time and after three months of incubation, which indicates a reduction in the decomposition rate and an increasing C/N ratio during the incubation. From the distribution between the decomposition rate and gas fluxes, we concluded that anaerobic decomposition rates do not have a significantly positive relationship with the fluxes of greenhouse gas emissions from the soil.

• Journal of Ecology and Environment
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• v.31 no.4
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• pp.291-295
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• 2008

Weight loss and nutrient dynamics of oak and pine leaf litter during decomposition were investigated from December 2005 through June 2008 at Mt. Worak National Park as a part of National Long-Term Ecological Research Program in Korea. The decay constant (k) of oak and pine leaf litter were 0.314 and 0.217, respectively. After 30 months decomposition, remaining weight of oak and pine leaf litter was 45.5% and 58.1%, respectively. Initial C/N ratio of oak and pine leaf litter was 53.4 and 153.0, respectively. Carbon % of initial oak and pine leaf litter was similar with each other; however, nitrogen content of initial oak leaf litter (0.85%) was greater than that of initial pine leaf litter (0.33%). N and P concentration in both decomposing leaf litter increased significantly during decomposition. There was no net N and P mineralization period in decomposing pine leaf litter. K, Ca and Mg concentration in both decomposing leaf litter showed different pattern with those of N and P. After 30 months decomposition, remaining nutrients in oak and pine leaf litter were 97.7 and 216.2% for N, 123.2 and 216.5% for P, 39.3 and 44.8% for K, 47.9 and 40.6% for Ca, 30.7 and 51.2% for Mg, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.124-130
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• 2004

This study was carried out to evaluate the effects of condensed molasses soluble (CMS) treatment on the mineralization of N, chemical properties and soil microbial population under the incubation condition with unsaturated water content during the 7 weeks at $25^{\circ}C$ in the different levels of CMS application. The results indicated that the total nitrogen content of soil was increased with increasing application rate of CMS and this trend was maintained up to 7 weeks. With CMS treatment content of $NH_4-N$ was gradually decreased. However, the content of $NO_3-N$ in the soil was gradually increased with incubation time due to the nitrification under the unsturated water condition. The CMS treatment increased the microbial populations such as bacteria, actinomycetes and fungi, which may be due to the availability of more nutrients such as amino acids, sugars and other minor elements from CMS. The pH of soil was found to be reduced by the addition of CMS, Whereas, electrical conduvtivity of soil was correspondingly increased with increasing application rate of CMS.

• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.98-104
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• 1997

Soil pollution intensity at Mt. Namsan in Seoul city which was expected to show significant soil contamination due to long-term air pollution was evaluated by comparing soil chemical properties at Mt. Kyebangsan in Hongcheon area as a control, and the bacteria participating in nitrogen or sulfur mineralization were assayed simultaneously in order to evaluate the validity of N and/or S mineralization bacteria as an index of soil contamination. The soil of Mt. Namsan showed 10 times higher concentration of hydrogen ion compared to that of Mt. Kyebangsan, which indicated that the soil had relatively been acidified seriously. Especially, large amount of canons were thought to be leached out from the soil, while the amount of extractable Al was getting larger and larger, which result in serious problems in soil ecosystem of the mountain. I could infer from soil chemical properties of the four study sites that the major reason of soil acidification was SOx deposition. However, the sulfur-reducing bacteria were not significantly different between the two regions, which indicated that the microbial dynamics of the soil ecosystem was not controlled by simple factor, but by multiple factors. By the way, the dynamics of bacteria participating in denitrification process was different between the two regions, which was more active at Mt. Kyebangsan than at Mt. Namsan. Thus, the microbial assay for nitrogen mineralization is desirable to be examined as a tool for evaluating soil health or microbial activity in soil ecosystem.

• Journal of the Korea Organic Resources Recycling Association
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• v.6 no.2
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• pp.81-93
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• 1998

In order to estimate the an adequate application level for dry matter production of orchardgrass(Dactylis glomerata L.) were investigated in different application levels of food waste compost and mineral nitrogen in 3 cuttings per annum, and to evaluated the soil improving effect of food waste compost. Annual food waste compost and mineral nitrogen were applied at levels of 0, 10, 20, 40 and $60ton\;ha^{-1}$, and 0, 90, 180 and $270kg\;ha^{-1}$, respectively. Significantly higher dry matter yield of orchardgrass obtained were ranges of $8.92{\sim}9.70ton\;ha-1$ at levels of $180{\sim}270kg\;ha^{-1}\;yr^{-1}$ than that of other levels of mineral nitrogen. Relative yield of each cut to annual dry matter yield were 32.0% 49.2% and 18.8% for 1st cut, 2nd cut and 3rd cut in mineral nitrogen treatment. Significantly higher dry matter yield of orchardgrass obtained were ranges of $8.04{\sim}8.90ton\;ha^{-1}$ at levels of $20{\sim}60ton\;ha^{-1}\;yr^{-1}$ than that of other levels of food waste compost. The efficiency of dry matter production to application of mineral nitrogen(kg DM $kg^{-1}$ N) were 21.2, 19.0 and 15.6kg at levels of 90, 180 and $270kg\;ha^{-1}\;yr^{-1}$, respectively. Higher efficiency of dry matter Production obtained were 27.6~20.2 kg at levels of $90{\sim}180kg\;ha^{-1}$ of mineral nitrogen applied to $20ton\;ha^{-1}$ of food waste compost, it may due to accelerated mineralization by mineral nitrogen application. Highest efficiency of dry matter production to application of food waste compost (kg DM $ton^{-1}$ FWC) obtained was 71.0 kg at level of $40ton\;ha^{-1}\;yr^{-1}$. Maximum dry matter yield of orchardgrass obtained were $9.98ton\;ha^{-1}$ at limiting level of mineral nitrogen of $358.5kg\;ha^{-1}$ and $9.12ton\;ha^{-1}$ at limiting level of food waste compost of $49.3ton\;ha^{-1}$ per annum, respectively. Ranges of $20{\sim}49.3ton\;ha^{-1}$ of food waste compost and $180{\sim}358.5kg\;ha^{-1}$ of mineral nitrogen were estimated an adequate levels for increase in dry matter production, and to maintenance for orchardgrass pastures. Application of food waste compost was affected to improve the soil characteristics.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.3
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• pp.81-88
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• 2000

Composting of N-rich wastes such as food waste and wastewater sludges can be associated loss of with substantial gaseous N, which means loss of an essential plant nutrient but may also lead to environmental pollution. We investigated the behavior of nitrogenous materials during the first high-rate phase in composting of food waste. Air dried food waste was mixed with shredded waste paper or wood chip and reacted in a bench scale composting reactor. Samples were analyzed for pH, ammonia, oxidized nitrogen and organic nitrogen. The volatilized ammonia nitrogen was also analyzed using sulfuric acid as an absorbent solution. Initial progress of composting reaction greatly influenced the ammonification of organic nitrogen. A well-balanced composting reaction with an addition of active compost as an inoculum resulted in the promoted mineralization of organic nitrogen and volatilization of ammonia. The prolongation of initial low pH period delayed the production of ammonia. It was also found that nitrogen loss was highly dependent on the air flow supplied. With an increase in input air flow, the loss of nitrogen as an ammonia also increased, resulted in substantial reduction of ammonia content in compost. The conversion ratio of initial nitrogen into ammonia was in the range of 28 to 38% and about 77~94% of the ammonia produced was escaped as a gas. Material balance on the nitrogenous materials was demonstrated to provide an information of importance on the behavior of nitrogen in composting reaction.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.4
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• pp.32-39
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• 2015

Objective of this study was to investigate characteristics of inorganic components contained in liquid fertilizer produced using seaweed by adding microorganisms and molasses. Addition of dry yeast to liquid fertilizer resulted in little change in pH and considerable increase in EC with high EC value compared to other liquid fertilizers which have microorganisms additives. Also, it was appeared that the dry yeast-added treatment had higher $NH_4-N$ concentration than other treatments. In the other hand, addition of molasses resulted in low pH compared to the control which has no additives, and EC was not different depending on the amount of molasses. $NH_4-N$ concentration in the 2% molasses added treatment was lowest and it showed a significant difference in the no and 1% molasses added treatments. In conclusion, it was shown that addition of dry yeast to liquid fertilizer increased ammonium nitrogen concentration by accelerating nitrogen mineralization, while molasses has an effect of inhibiting nitrogen mineralization. With application of organic liquid fertilizer containing seaweed increased the fresh weight of chinese cabbage.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.4
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• pp.87-94
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• 2014

Objective of this study was to investigate characteristics of inorganic components contained in liquid fertilizer produced using bone powder and rice bran by adding dry yeast and molasses. Addition of dry yeast to liquid fertilizer resulted in little change in pH, considerable increase in EC, and it showed high EC value compared to the control which has no additives. Also, it was appeared that the dry yeast-added treatment had higher at $2,936mg{\cdot}L^{-1}$ of $NH_4$-N concentration than the control which had $1,782mg{\cdot}L^{-1}$. In the other hand, addition of molasses resulted in low pH and slightly low EC, as compared to the control. $NH_4$-N concentration in the no added molasses treatment was $2,936mg{\cdot}L^{-1}$ higher than its molasses added treatment which had $2,378mg{\cdot}L^{-1}$. In conclusion, it was shown that addition of dry yeast to liquid fertilizer increased ammonium nitrogen concentration by accelerating nitrogen mineralization, while molasses has an effect of inhibiting nitrogen mineralization and enhancing the characteristics of fermentation. With application of organic liquid fertilizer containing bone powder and rice bran increased the fresh weight of Allium tuberosum.

• Journal of Aquaculture
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• v.13 no.1
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• pp.87-99
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• 2000

Field survey on the variational characteristics of water quality and chlorophyll a concentraion were carried out at the 25 stations for four seasons in Kogum-sudo(Straits) southern coast of Korean Peninsula from Feburuary to October in 1993. We made an analysis on biological factor as chlorophyll a concentraion as well as physicio-chemical factors such as water temperature salinity sigma-t transparency dissolved oxygen(DO) chemical oxygen demand(COD) nutrients (ammonia, nitrite, nitrate, phosphate, and silicate) N/P ratio and suspended solid(SS). The waters in the Kogum-sudo were not stratified due to the tidal mixing. And the high productivity in photic layer were supported by high nutrients concentration from bottom waters. The high concen-trations of suspended solid in straits had a bad influence upon marine biology of nature and cultivations. In Kogum-sudo had a sufficient nutrients for primary productivity during a year. Especially phosphate and inorganic nitrogen were high the other side silicate was very low. The source of nutrients supply depend on rather mineralization of organic matters and input of seawater from outside than input of freshwaters from lands. Phytoplankton biomass as measured by chlorphyll a concentratiion was very high all the year round and it was controlled by the combination o f several environmental factors especially of phosphate in summer and dissolved nitrogen in other seasons.

• Journal of Korean Society of Rural Planning
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• v.8 no.1 s.15
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• pp.60-68
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• 2002

A Modified CREAMS model, CREAMS-PADDY was developed to simulate the hydrology and nutrient transport at an irrigated rice paddy. The hydrology at a paddy was simulated by a daily water balance routine which reflects daily inflow, outflow, and water level changes. The soil erosion was simulated using modified USLE. The nutrient transport for total nitrogen and phosphorus were depicted for various phases of each constitute such as extraction, percolation, mineralization, and plant uptakes. Field monitoring was conducted to investigate the water quality changes at a paddy field at three times a week during the growing season of 1996. The proposed model simulates the water quality of the paddy reasonably well, and is found to be applicable to field conditions.