• The Korean Journal of Ecology
• /
• 제20권5호
• /
• pp.329-337
• /
• 1997

Study of population density and biomass of soil microarthropods in soil, herbaceous leaf litter and wood leaf litter was conducted at 4 sites with different flora in Mt. Jumbong, a nature reserve area, in Korea from Aug. 1994 to May 1996. Total 47, 849 individuals of soil microarthropods in soil were collected and identified into 6 different classes, and 16 orders. The composition, densities, and dominant group of soil microarthropods were different among 4 sampling sites. Collembola was the most abundant group with 50.7% at South-facing slope and 50.6% at the North-facing slope. But Acari was the most abundant group with 49.8% at Altitude 900m site and 47.7% at Altitude 1100m site. Two group ranged 87-95% of total individuals. A/C ratio was less than 1.0 at 4 sampling sites during the all sampling seasons. As a result of biomass evaluation, rato of Acari was decreased but ratio of Diplopoda, coleoptera, Araneae, Diptera and Chilopoda was increased. About 70% of total orders and densities were found in less than 5cm soil depth. The composition, densities, and dominant group of soil microarthropods were different among soil, herbaceous litter and wood litter. Collembola was the most abundant group in herbaceous and wood litter. A/C ratio was less than 1.0 in litter during the sampling seasons. As a result of biomass evaluation in litter, ration of Araneae and Collembola was very high, but ratio of Acari was low.

• 한국수산과학회지
• /
• 제36권6호
• /
• pp.757-761
• /
• 2003

Spatial distribution and biomass of commercial shellfish were investigated in the Saemangeum tidal flat on the west coast of Korea during August 1999. Thirteen species of shellifsh were collected. Major dominant species of the study area were Umbonium thomasi with a density of $6.7\;ind.{\cdot}m^{-2}\;(38.2\%)$, Mactra veneriformis with $6.6\;ind.{\cdot}m^{-2}\;(37.4\%)$ and Reticunassa festiva with $1.3\;ind.{\cdot}m^{-2}\;(7.2\%)$. Commercially important species such as M. veneriformis ($90.7\;ind.{\cdot}m^{-2}\;69.3\%$), M. lusoria ($15.6\;ind.{\cdot}m^{-2}\;11.9\%)$), C. sinensis ($8.7\;ind.{\cdot}m^{-2}\;6.7\%)$) were dominant in total weight. Most of the shellfish were distributed between the mid-littoral and sub-littoral zones, but C. sinensis and L. flexuosa were distributed mainly in the polluted areas of the supra-littoral zone. The spatial distribution pattern of each shellifsh species generally resembles the Mangyeong and Dongjin estuary. Biomass of commercially important species, M. veneriformis, M. lusoria, C. sinensis and Ruditapes philippinarum in the tidal flat (ca. 850 ha) was estimated to be 774, 135, 67 and 10 tons, respectively.

• 한국환경농학회지
• /
• 제36권4호
• /
• pp.223-229
• /
• 2017

BACKGROUND: Tillage systems and fertilization play an important role in crop growth and soil improvement. This study was conducted to determine the effects of tillage and fertilization on the microbial biomass C and dehydrogenase activity of soils in a field under cultivation of soybean. METHODS AND RESULTS: An experimental plot, located in the temperate climate zone, was composed of two main sectors that were no-tillage (NT) and conventional tillage (CT), and they were subdivided into four plots, respectively, in accordance with types of fertilizers (non fertilizer, chemical fertilizer, hairy vetch, and liquid pig manure). Microbial biomass C and dehydrogenase activity were evaluated from May to July in 2016. The microbial biomass C and dehydrogenase activity of NT soils were significantly higher than those of CT in all fertilizer treatments, and they were further increased in hairy vetch treatment than the other fertilizer treatments in both NT and CT. The dehydrogenase activity was closely related to microbial biomass C. CONCLUSION: It is concluded that application of green manure combined with no-tillage can provide viable management practices for enhancing microbial properties of soil.

• 한국자원식물학회지
• /
• 제11권1호
• /
• pp.80-85
• /
• 1998

The influence of elevated CO2 and temperature on growth parameters, biomass production and its partitioning of rice (Oryza sativa L.cv. Chukwangbyeo) were investigated in the three experiments (1991-1993). Rice plants were grown from transplanting to harvest at either ambient(350ppm) or elevated CO2 concentrations (690 or 650ppm) in combination with either four or seven temperature regimes ranging form ambient temperature (AT) to AT plus 3$^{\circ}C$.From transplanting to panicle initiation, crop growth rate (CGR) was enhanced by up to 27% with elevated CO2 , primarily due to an an increase in leaf area index. although net assimilatiion rate was also greater at elevated CO2. The effect of elevated CO2 varied with temperature. During the reproductive phase, CGR declined linearly with increased temperature, and was greater at elevated CO2 . Elevated CO2 increased final crop biomass and panicle weight 30% respectively at AT(27.6$^{\circ}C$ : 1991) . However, there was no significant effect of elevated CO2 on panicle weight at AT plus 3$^{\circ}C$, where severe spikelet sterility occurred. There was no significant effect of elevated CO2 on panicle weight at AT plus 3$^{\circ}C$, where severe spikelet sterility occurred. There was also no effect of CO2 on biomass pratitioning into vegetative and reproductive organs (harvest index)) at AT, although higher temperature could affect that by inducing spikelet sterility. These results suggest that elevated CO2 could enhance rice producivity througth promoted growth and biomass production , but its positive effects may be less at higher temperatures.

• 한국입자에어로졸학회지
• /
• 제17권4호
• /
• pp.125-132
• /
• 2021

Fresh PM_2.5 smokes emitted from combustion of four biomass materials (pellet, palm fruit fiber (PFF), PKS, and sawdust) in a laboratory-controlled environment were characterized using an attenuated total reflectance-fourier transform infrared (ATR-FTIR) technique. In smoke samples emitted from combustion of pellets, PFF and PKS, which is being used as boiler fuels for greenhouses in rural areas, the organic carbon/elemental carbon (OC/EC) ratios in PM_2.5 were very high (14.0-35.5), whereas in sawdust smoke samples they were significantly low (<4.0) due to the combustion method close to flaming combustion. ATR-FTIR analysis showed that OH(3400-3250 cm^-1), CH₃(2958-2840 cm^-1), CH₂(2910 cm^-1 and 2850 cm^-1), ketone(1726-1697 cm^-1), C=C(1607-1606 cm^-1 and 1515-1514 cm^-1), lignin (1463-1462 cm^-1 and 1430-1428 cm^-1) and -NO₂(1360-1370 cm^-1) peaks were identified in all biomass burning (BB) smoke samples. However, additional peaks appeared depending on the type of biomass. Among the four types of biomass materials, an additional peak of the methylene group CH₃(2872-2870 cm^-1) appeared only in PFF and PKS smoke samples, and a peak of C=O(1685 cm^-1) was also confirmed. And in the case of PKS smoke samples, a peak of aromatic C=C(1593 cm^-1 and 1476 cm^-1) that did not appear in other BB samples was also observed. This indicates that the molecular structure of organic compounds emitted during BB differs depending on the type of biomass materials. The results of this study are expected to provide valuable information to more specifically reveal the effect of BB on PM_2.5 collected in the atmospheric environment.

• 한국환경농학회지
• /
• 제36권2호
• /
• pp.73-79
• /
• 2017

본 연구는 농가에서 버려지는 부산물을 탄화물로 변환한 후 토양에 적용하여 토양의 화학적 특성 변화와 온실가스 발생량을 비교하였다 탄화물로의 활용은 세 가지의 장점이 있었다. 첫 번째 버려지는 자원은 활용하여 재이용한 측면, 두 번째 농경지의 토양탄소 함량을 증진 시킬 수 있는 측면, 세 번째 농경지에서 발생하는 아산화질소를 줄일 수 있는 측면에서 유용할 것으로 판단된다. 하지만 $N_2O$ 감축기작에 대한 정확한 파악을 위해 질소순환과 연계된 추가적인 연구가 필요하다.

• 한국수소및신에너지학회논문집
• /
• 제21권6호
• /
• pp.587-594
• /
• 2010

Hydrogen is an alternative fuel for the future energy which can reduce pollutants and greenhouse gases. Synthesis gas has played an important role of synthesizing the valuable chemical compounds, for example methanol, DME and GTL chemicals. Renewable biomass feedstocks can be potentially used for fuel and chemicals. Current thermal processing techniques such as fast pyrolysis, slow pyrolysis, and gasification tend to generate products with a large slate of compounds. Lignocellulose feedstocks such as forest residues are promising for the production of bio-oil and synthesis gas. Pyrolysis and gasification was investigated using thermogravimetric analyzer (TGA) and bubbling fluidized bed gasification reactor to utilize forest woody biomass. Most of the materials decomposed between $320^{\circ}C$ and $380^{\circ}C$ at heating rates of $5{\sim}20^{\circ}C$/min in thermogravimetric analysis. Bubbling fluidized bed reactor was used to study gasification characteristics, and the effects of reaction temperature, residence time and feedstocks on gas yields and selectivities were investigated. With increasing temperature from $750^{\circ}C$ to $850^{\circ}C$, the yield of char decreased, whereas the yield of gas increased. The gaseous products consisted of mostly CO, $CO_2$, $H_2$ and a small fraction of $C_1-C_4$ hydrocarbons.

• KSBB Journal
• /
• 제27권2호
• /
• pp.97-102
• /
• 2012

In the present study, the biomass productivity of two green microalgae (Chlorella sp. and Dunaliella salina DCCBC2) were assessed in a 12 L tubular photobioreactor under optimum culture conditions. In the batch culture optimization process, the Chlorella sp. biomass was obtained as 1.2 g/L under atmospheric air as a sole $CO_2$ source and other culture conditions as follows: light intensity, temperature, pH, $NH_4Cl$ and $K_2HPO_4$ were 100 ${\mu}E/m^2/s$, $27^{\circ}C$, 7.0, 20.0 mM and 2.0 mM, respectively. On the other hand, 2.9 g/L of D. salina DCCBC2 biomass production was observed under the following conditions: light intensity, temperature, pH, $KNO_3$ and $K_2HPO_4$were 80 ${\mu}E/m^2/s$, $27^{\circ}C$, 8.0, 3.0 mM and 0.025 mM, respectively. At 1% $CO_2$ supply to the reactor, the Chlorella sp. production was reached 1.53 g/L with 25% increment under the same operating conditions. In addition, the maximum D. salina DCCBC2 biomass was observed as 3.40 g/L at 3% $CO_2$ concentration. Based on the aforementioned optimized conditions, the dilution rate and maximal biomass productivity of Chlorella sp. and D. salina DCCBC2 in the continuous cultivation were 0.4/d and 0.6 g/L/d and 0.6/d and 1.5 g/L/d, respectively.

• Journal of Ecology and Environment
• /
• 제34권4호
• /
• pp.401-410
• /
• 2011

We assayed the effects of simulated acid rain on the mass loss, $CO_2$ evolution, dehydrogenase activity, and microbial biomass-C of decomposing Sorbus alnifolia leaf litter at the microcosm. The dilute sulfuric acid solution composed the simulated acid rain, and the microcosm decomposition experiment was performed at 23$^{\circ}C$ and 40% humidity. During the early decomposition stage, decomposition rate of S. alnifolia leaf litter, and microbial biomass, $CO_2$ evolution and dehydrogenase activity were inhibited at a lower pH; however, during the late decomposition stage, these characteristics were not affected by pH level. The fungal component of the microbial community was conspicuous at lower pH levels and at the late decomposition stage. Conversely, the bacterial community was most evident during the initial decomposition phase and was especially dominant at higher pH levels. These changes in microbial community structure resulting from changes in microcosm acidity suggest that pH is an important aspect in the maintenance of the decomposition process. Litter decomposition exhibited a positive, linear relationship with both microbial respiration and microbial biomass. Fungal biomass exhibited a significant, positive relationship with $CO_2$ evolution from the decaying litter. Acid rain had a significant effect on microbial biomass and microbial community structure according to acid tolerance of each microbial species. Fungal biomass and decomposition activities were not only more important at a low pH than at a high pH but also fungal activity, such as $CO_2$ evolution, was closely related with litter decomposition rate.

• 동력기계공학회지
• /
• 제22권1호
• /
• pp.79-86
• /
• 2018

Many countries have conducted extensive studies for biomass co-firing to enhance the durability of reactor on high-temperature corrosion. However, due to the complicated mechanisms of biomass co-firing, there have been limitations in accurately determining the current state of corrosion and predicting the potential risk of corrosion of power plant. In order to solve this issue, this study introduced Lab-scale corrosion system to analyze the corrosion characteristics of the A213 T91 material under the biomass co-firing conditions. The corrosion status of the samples was characterized using SEM/EDS analysis and mass loss measurement according to various biomass co-firing conditions such as corrosion temperature, $SO_2$ concentration, and corrosion time. As a result, the corrosion severity of A213 T91 material was gradually increased with the increase of $SO_2$ concentration in the reactor. When $SO_2$ concentration was changed from 0 ppm to 500 ppm, both corrosion severity and oxide layer thickness were proportionally increased by 15% and 130%, respectively. The minimum corrosion was observed when the corrosion temperature was $450^{\circ}C$. As the temperature was increased up to $650^{\circ}C$, the faster corrosion behavior of A213 T91 was observed. A213 T91 was observed to be more severely corroded by the effect of chlorine, resulting in faster corrosion rate and thicker oxide layer. Interestingly, corrosion resistance of A213 T91 tended to gradually decrease rather than increases as the oxide layer was formed. The results of this study is expected to provide necessary research data on boiler corrosion in biomass co-firing power plants.