• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.299-308
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• 2004

In order to elucidate the behavior of bensulfuron-methyl, a sulfonylurea herbicide, in a soil/plant microecosystem, rice plants (Oryza sativa L.) were grown for 12 weeks in the specially made stainless steel pots (17cm I.D. $\times$ 10cm H.) containing two different paddy soils treated with fresh and 13-week-aged residues of [phenyl-$^{14}C$]bensulfuron-methyl, respectively. During the aging period, the mineralization to $^{14}CO_2$ from soil A (OM, 3.59%; CEC, 7.65 $cmol^+\;kg^{-1}$; texture, sandy clay loam) and B (OM, 1.62%; CEC, 4.51 $cmol^+\;kg^{-1}$; texture, sandy loam) amounted to 6.79 and 10.15% of the originally applied $[^{14}C]$bensulfuron-methyl, respectively. The amounts of $^{14}CO_2$ evolved from the soils with fresh residues were higher than those from the soils with aged residues. At harvest after 12-week growing, $^{14}C$-radioactivity absorbed and translocated into rice plants from soils A and B containing fresh residues of bensulfuron-methyl was 1.53 and 4.40%, while 4.04 and 6.37% in the two soils containing aged residues, respectively. Irrespective of aging and soil type, the $^{14}C$-radioactivity remaining in soil ranged from 80.41 to 98.87% of the originally applied $[^{14}C]$bensulfuron-methyl. The solvent extractability of tile soils was $39.25\sim70.39%$, showing the big differences among the treatments. Most of the nonextractable soil-bound residues of $[^{14}C]$bensulfuron-methyl were incorporated into the fulvic acid fraction$(61.32\sim76.45%)$. Comparing the microbial activity of the soils with rice plants grown with that of the soils without them, the former was $1.6\sim3.0$ times higher than the latter. However, it did not correlate with the $^{14}CO_2$ evolution.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.1
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• pp.76-82
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• 1986

A laboratory experiment was conducted to find out the denitrification rate upon the levels of nitrogen and source of organic matter in submerged sandy and sandy loam soil. The results obtained were sumarized as follows; 1. Evolution of nitrous oxide was increased at 1st and 10 days after incubation. And dinitrogen was increased at 1st and 30 days after incubation. Applications of green manure was enhanced the evolution of nitrous oxide ($N_2O$) and dinitrogen ($N_2$). 2. The cumulative denitrification rates at 50 days was high in Gyuam sandy loam soil (O-M: 1.52%) than that of Hamchang sandy soil (O-M: 3.81%). On the other hand, the cumulative emission of dinitrogen was high in Gyuam sandy loam soil while nitrous oxide was high in Hamchang sandy soil. The total mount of denitrification rate was high in order of green manure > rice straw > compost > control soil. 3. Increases of fertilizer nitrogen was enhanced the rate of emission of dinitrogen and nitrous oxide during the incubation time. 4. According to Michaelis-Menten kinetic equation, denitrification rates and reaction efficiency were remarkably increased by application of readily decomposable organic matter with in higher organic matter content of soil. 5. The negative relationship was observed between the evolution of dinitrogen and carbon ($CO_2+CH_4$) while the nitrous oxide with carbon was positive. 6. Under the this experiment conditions 1 mg of carbon was required for production of 4 mg N as $N_2O$ and 3 mg of N as $N_2$, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.886-891
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• 2010

Importance of climate change and its impact on agriculture and environment have increased with a rise of greenhouse gases (GHGs) concentration in Earth's atmosphere, which caus an increase of temperature in Earth. Greenhouse gas emissions such as carbon dioxide ($CO_2$), methane ($CH_4$) and nitrous oxide ($N_2O$) in the Upland field need to be assessed. GHGs fluxes using chamber systems in two upland fields having different soil textures during pepper cultivation (2005) were monitored under different soil textures at the experimental plots of National Academy of Agricultural Science (NAAS), Rural Development Administration (RDA) located in Suwon city, Korea. $CO_2$ emissions were 12.9 tonne $CO_2\;ha^{-1}$ in clay loam soil and 7.6 tonne $CO_2\;ha^{-1}$ in sandy loam soil. $N_2O$ emissions were 35.7 kg $N_2O\;ha^{-1}$ in clay loam soil and 9.2 kg $N_2O\;ha^{-1}$ in sandy loam soil. $CH_4$ emissions were 0.054 kg $CH_4\;ha^{-1}$ in clay loam soil and 0.013 kg $CH_4\;ha^{-1}$ in sandy loam soil. Total emission of GHGs ($CO_2$, $N_2O$, and $CH_4$) during pepper cultivation was converted by Global Warming Potential (GWP). GWP in clay loam soil was higher with 24.0 tonne $CO_2$-eq. $ha^{-1}$ than that in sandy loam soil (10.5 tonne $CO_2$-eq. $ha^{-1}$), which implied more GHGs were emitted in clay loam soil.

• Journal of Korea Water Resources Association
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• v.34 no.4
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• pp.335-345
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• 2001

The objective of this research is to analyze the hydrological environment changes in Daechung Dam Basin due to the global warming. GCM simulation results are used to predict the possible changes in precipitation and temperature. The changes of potential evapotranspiration, soil moisture and runoff due to the changes of precipitation and temperature are analyzed using a conceptual water balance model. From the simulation results using the water balance model for lx$CO_2$ and 2x$CO_2$ situations, it has been found that the runoff would decrease in Winter, but increase in Summer and Fall due to the global warming. Therefore, it is predicted that the frequency of drought and flood occurrences in Daechung Dam Basin would be increased in 2x$CO_2$ condition.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.8-18
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• 1999

The degradation of a fungicide, $^{14}C$-propiconazole, in sterile and nonsterile soil from different depths was investigated. $^{14}C$-propiconazole plus propiconazole standard was treated on the soil at the rate of 7.55 mg/kg and the soil was incubated at $25^{\circ}C$ for 20 weeks. The amounts of $^{14}CO_{2}$ solvent extractable and non-extractable $^{14}C$, and degradation products of $^{14}C$-propiconazole were investigated during incubation time. The relative amounts of $^{14}CO_{2}$ released in the sterile and nonsterile soils were ranging from 0.7 to 1.3% and from 4.8 to 7.6% of applied $^{14}C$, repectively. The amounts of solvent non-extractable residues in the sterile and nonsterile soils were ranging from 11.2 to 22.1% and from 22.2 to 41.9% of of applied $^{14}C$, repectively. The amounts of solvent non-extractable residues were increased with incubation time and most of $^{14}C$ were detected in the humin fraction. The hydroxylated and ketone compound were confirmed as a degradation products of propiconazole by GC/MS analysis, whereas parent compound was detected in sterile soil, which suggested that propiconazole was not degraded biologically under the sterile soil. From the results of volatilization, mineralization and degradation of propiconazole, propiconazole was stable chemically and bilogically in soil.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.911-916
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• 2010

Rice paddy fields and crop residue burning are a major source of methane ($CH_4$) emissions, a potent greenhouse in agriculture. This study was conducted to assess $CH_4$ emissions in Korea cropland sector from 1990 to 2008. Greenhouse gas emissions from the cropland sector are calculated in two categories: 4C (Rice cultivation) and 4F (Field burning). In 4C: Rice Cultivation, methane emissions from paddy fields (continuously flooded and intermittently flooded) cultivated for rice production had decreased from 395 $CH_4$ $10^3$ Mg in 1990 to 297 $CH_4$ $10^3$ Mg in 2008. $CH_4$ emissions converted into $CO_2$ equivalent were 8,303 $CO_2$-eq. $10^3$ Mg in 1990 and 6,229 $CO_2$-eq. $10^3$ Mg in 2008. Greenhouse gas emissions from paddy field in Korea showed that it was gradually going down as the cultivation area decreased. In 4F: Field Burning, methane emissions by burning crop residue increased from 2,502 $CH_4$ Mg in 1990 to 2,726 $CH_4$ Mg in 2008. Emissions converted $CH_4$ into $CO_2$ equivalent were 53 $CO_2$-eq. $10^3$ Mg in 1990 and 57 $CO_2$-eq. $10^3$ Mg in 2008. Total emissions of $CH_4$ from the cropland sector declined from 8,356 $CO_2$-eq. $10^3$ Mg in 1990 to 6,287 $CO_2$-eq. $10^3$ Mg in 2008.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.62-69
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• 1992

A series of laboratory experiment was conducted to find out the effects of physico-chemical, microbiological and commercial inhibitors on the odorous gas evolution in the fermentation of livestock feces. The results obtained were summarized as follows. 1. The rate and amount of evolution of gas were the highest at 7 days after incubation, thereafter gradually decreased until 24 days after incubation. 2. The rate and amount of gases were evolved in order of $CO_2>N_2O>CH_4>NH_3>N_2S$, respectively. 3. The highest amount of methane gas was evolved from the poultry feces, those of carbon dioxide and nitrous oxide were evolved from the pig feces, and that of hydrogen sulfide was dominantly evolved from the cattle feces. 4. Negative correlation were obtained between the total amounts of $NH_3$ and $CH_4$, $CO_2$ and $CH_4$, $N_2O$ and $CH_4$, $N_2O$ and $CH_4$, while positive correlations were obtained between the amounts of $CO_2$ and $N_2O$, $CO_2$ and $NH_3$, and $NH_3$ and $N_2O$, respectively. 5. There was no significantly inhibiting effect obtained that the application of commercial gas inhibitor as VK 88. On the other hand there was significantly inhibiting effect obtained when application of fertile paddy soil and photosynthetic bacteria to the fermentation of livestock feces.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.502-509
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• 2013

To estimate greenhouse gas (GHG) emission, we established inventory of conventional rice cultivation from farmers in Gunsan and Iksan, Jeonbuk province in 2011~2012. This study was to calculate carbon footprint and to analyse the major factor of GHGs. We carried out a sensitivity analysis using the analyzed main factors of GHGs and estimated the mitigation potential of GHGs. Also we tried to suggest agricultural methods to reduce GHGs that farmers of this case study can apply. Carbon footprint of rice production unit of 1 kg was 2.21 kg $CO_2.-eq.kg^{-1}$. Although amount of $CO_2$ emissions is largest among GHGs, methane had the highest contribution of carbon footprint on rice production system after methane was converted to carbon dioxide equivalent ($CO_2$-eq.) multiplied by the global warming potential (GWP). Source of $CO_2$ in the cultivation of rice farming is incomplete combustion of fossil fuels used by agricultural machinery. Most of the $CH_4$ emitted during rice cultivation and major factor of $CH_4$ emission is flooded paddy field in anaerobic condition. Most of the $N_2O$ emitted from rice cultivation process and major sources of $N_2O$ emission is application of fertilizer such as compound fertilizer, urea, orgainc fertilizer, etc. As a result of sensitivity analysis due to the variation in energy consumption, diesel had the highest sensitivity among the energies inputs. If diesel consumption is reduced by 10%, it could be estimated that $CO_2$ potential reduction is about 2.5%. When application rate of compound fertilizer reduces by 10%, the potential reduction is calculated to be approximately 1% for $CO_2$ and approximately 1.8% for $N_2O$. When drainage duration is decreased until 10 days, methane emissions is reduced by approximately 4.5%. That is to say drainage days, tillage, and reducing diesel consumption were the main sources having the largest effect of GHG reduction due to changing amount of inputs. Accordingly, proposed methods to decrease GHG emissions were no-tillage, midsummer drainage, etc.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.2
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• pp.52-60
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• 2009

This study was conducted to quantify the soil respiratory $CO_2$ emission (SR) in an apple orchard and to determine its relationship with key environmental factors such as air temperature, soil temperature and soil moisture content. Experiment was made over the period from 23 April 2007 to 31 March 2008 in 'Fuji' apple orchard of National Institute of Horticultural and Herbal Science in Suwon, Gyeonggi-do, Korea. The SR was measured by using the automatic opening/closing chamber system based on a closed method. Diurnal variations in SR showed an increase around 0700 hours with increasing soil temperature, its peak between 1400 and 1500 hours, and then a gradual decrease thereafter. Daily variations in SR depended largely on soil and air temperatures over the year, ranging from 0.8 to 13.7 g $CO_2$ $m^{-2}d^{-1}$. During the rainy spell in summer (July$\sim$Autumn) with higher temperature and more precipitation, the SR was lower than that in the spring (May$\sim$June) with moderate temperature. The SR showed a significant exponential relationship with soil temperature ($r^2=0.800$) and air temperature ($r^2=0.805$), but not with soil moisture content ($r^2=0.160$). The $Q_{10}$ values of SR with annual soil temperature and air temperature were 2.0 and 1.9, respectively. The annually integrated SR was 19.6 ton $CO_2$ $ha^{-1}$.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.320-326
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• 1997

In order to elucidate the degradation characteristics of the herbicide imazapyr in soil, mineralization to $^{14}CO_2$and adsorption were investigated using eight types of soils with the different physico-chemical properties. The results obtained were as follows: 1. During the incubation period of 12 weeks after the treatment of imazapyr, the amounts of $^{14}CO_2$ evolved from 8 types of soils with different properties ranged from 1.5 to 4.9% of the originally applied $^{14}C$ activities. Soil C, G, and H with low pH and high organic matter showed low $^{14}CO_2$evolution, whereas soil B and D with high pH and low organic matter did high $^{14}CO_2$ evolution. 2. Time for reaching the equilibrium concentrations in the adsorption experiment of imazapyr in soils was about 3 hours at $25^{\circ}c$ in soil C, D, G, and H. Imazapyr was adsorbed in the range of 0.25${\sim}$28.32% in soils with different physico-chemical properties. Among the soil parameters, organic matter content was the most influential in imazapyr adsorption on soil. The Freundlich adsorption coefficient $(K_f)$ increased 5.5 to 25.6 times as organic matter content increased 2.0 to 21.3 times. Hence it seems that the extent to which soil organic matter contributes to imazapyr adsorption is greater than that of clay mineral. $K_f$ values for the soils tested were 0.44, 0.08, 0.65, and 2.05 in soil C, D, G, and H, respectively. In all the soils tested, $K_f$ values had a strong resemblance to K_$K_d$.