• Korean Journal of Environmental Agriculture
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• v.8 no.1
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• pp.55-59
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• 1989

To determine the accurate C/N ratio of compost, biodegradable carbon and nitrogen in compost must be analyzed. In biodegradable nitrogen analyzed by Kjeldahl Method, nitrate and nitrite which are available for microbes can not be detected at all. By means of $F{\"{o}}rster$ Method, nitrate and nitrite can be detected. Therefore, various nitrogens in compost were analyzed by Kjeldahl and $F{\"{o}}rster$ Method to investigate the seasonal changes of various C/N ratios of compost. C/N ratios in compost analyzed by Kjeldahl and $F{\"{o}}rster$ Method were decreased rapidly within 2 weeks after composting, then were not changed to 6 weeks, and thereafter were decreased slowly with the lapse of composting time. C/N ratios analyzed by Kjeldahl Method were higher than those analyzed by $F{\"{o}}rster$ Method. C/N ratios of total carbon/total nitrogen analyzed by Kjeldahl Method were higher(5 as C/N ratio or 36%) than those of biodegradable carbon/biodegradable nitrogen analyzed by $F{\"{o}}rster$ Method. Highly positive correlations were observed among C/N ratios of total carbon/total nitrogen analyzed by Kjeldahl Method total carbon/total nitrogen analyzed by $F{\"{o}}rster$ Method and biodegradable carbon/biodegradable nitrogen analyzed by $F{\"{o}}rster$ Method one another.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.304-305
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• 2009

시설재배지의 토양화학성 변화는 작물재배 기간 시비한 화학비료에서 유래된 무기성분 뿐만아니라, 가축분퇴비의 질소성분의 토양잔류량이 요소비료 보다 9.4배 많아 염류집적 주 요인이라는 보고('05 경기도)가 시사하는 봐와 같이 유기자원으로 시용하는 가축분 등의 부산물비료의 무기화에서 유래된 비료성분이 토양염류집적 및 토양환경악화에 더 큰 영향을 미칠 수 있다. 시설재배지의 유기물자원 시용기준이 토양의 특성에 관계 없이 작물에 따라 양적인 시험성적이 주로되어 있으며, 토양검정에 의한 시용기준도 유기물함량에 따라 볏짚, 우분, 돈분 및 계분으로 돠어 있다. 일반노지와 달리 시설재배지에서는 유기물함량이 토양의 비옥도 및 작물생육에 영향을 미치는 것 보다는 토양의 전기전도도(EC)가 더 중요한 작물생육 조건이 될 수 있다. 따라서 토양의 특성에 따라 물질순환에 의한 유기자원 시용기준으로 개선할 필요성이 있다. 시설재배지의 장기적인 토양관리를 위하여 유기물자원에 의한 토양환경 개선 효과를 구명하고자. 무처리, 가축분부산 물비료 관행 시용 기준 대비 볏짚 등 5개의 유기자원을 토양의 무기태질소 함량 대비 유기자원의 탄소함량을 C/N율 10 조절량을 시용하여 시험하였고, 또한 토양의 전기전도도(EC)가 상이한 3개( <2.0 dS/m, 2.0~6.0 dS/m, 6.0 dS/m<)토양에 유기물자원(우드칩)을 C/N율 10, 20, 30 조절하여 수박을 시험작물로 비닐하우스에서 재배하여 수행하였다. 시험 후 토양의 전기전도도(EC)는 시험 전에 비하여 시험 후 토양에서 가축분부산물비료는7% 증가되었으나 유기물자원 처리는 26~33% 경감되는 효과가 있었다. 수박의 과중은 무처리를 제외하고 처리간에 차이가 없었다. 유기물자원 C/N율 조절간에는 시험전 토양의 EC에 따라 차이가 있어 C/N 10 조절에서는 26~44%, C/N 20 조절에서는 30~51%, C/N 30 조절에서는 27~48% 경감효과가 있었으며, 3토양의 평균 토양EC 경감율은 C/N 10, 20, 30 조절에서 각각 34, 39 및 38 % 이었다. 수박의 생육 및 과중은 토양의 C/N율 조절간에는 차이가 없었으나, 토양의 EC 간에는 토양의 EC가 6.0dS/m 이상 토양에서 가장 낮았다. 따라서 탄소원의 유기자원을 C/N율 조절에 의한 시용기준 개선으로 토양의 무기태질소와 토양의 전기전도도(EC)를 경감시켜 친환경적 토양관리와 수박의 수량과 품질을 향상시킬 수 있을 것으로 평가되었다.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.124-129
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• 1996

This experiment has been conducted to find out a effective decomposition method of popped rice hulls which are hard to be decomposed in vitro. It was found that the C/N ratio of 35 was better than the C/N ratio of 20 for improving the decomposition ratio of popped rice hulls. The addition of rice bran accelerated the decomposition of popped rice hulls. The real decomposition rate of popped rice hulls for 10 days was merely 8 percent. This poor decomposition ratio seemed to be come from the chemical constituent of rice hull which has 20 percent of silica content. It was considered that the addition of rice bran speeded up only the decomposition of bran itself by increasing the number of microorganisms. It was also observed that color changes developed from the decomposition of rice hulls proved not to be a yardstick for the degree of decomposition.

• Journal of Bio-Environment Control
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• v.21 no.1
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• pp.20-27
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• 2012

This experiment was conducted to evaluate the long-term effect of the elevated temperature and $CO_2$ concentration on the plant biomass, C/N ratio, and proximate composition of radish. Elevated temperature by 2~2.5 higher than ambient temperature decreased plant biomass by 39% in the spring and 26% in the autumn, respectively. Elevated $CO_2$ concentration by $220{\sim}230{\mu}mol\;mol^{-1}$ higher than ambient $CO_2$ concentration increased plant biomass especially in root. The elevated $CO_2$ concentration, however, could not compensate for the negative effect of elevated temperature on the plant biomass entirely. Elevated temperature increased T/R ratio by 86% in the spring and 60% in the autumn, respectively. Elevated temperature lowered C/N ratio and raised crude protein, crude fat, and ash content in radish root. On the contrary, elevated $CO_2$ concentration raised C/N ratio and lowered the crude protein, crude fiber, and ash contents. These results indicate that climate change affect the biomass yield and internal materials of radish depending on the extent of temperature and $CO_2$ concentration rise in the future.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.382-389
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• 1997

To study the optimum conditions of composing with sewage sludge, the variations of temperature and $CO_2$ generation amount during composting periods were investigated. The conditions were that sewage sludge added to bulking agents such as sawdust and rice hull were used and differently treated with microorganism seeding or not, initial C/N ratio, air flow rate and initial moisture contents. The results were summarized as follows : Seeding of 5% microorganism was higher temperature than not seeding. And using rice hull as bulking agents, and adjusting 21${\sim}$22 of initial C/N ratio, $200ml/l\;{\cdot}\;min$. of air flow rate and 64${\sim}$65% of initial moisture contents were higher temperature than any other conditions. Seeding of 5% microorganism was more $CO_2$ generation amount than not seeding. And using saw dust was more $CO_2$ generation amount than using rice hull as bulking agents. In the case of initial C/N ratio, adjusting 21${\sim}$42 was also more $CO_2$ generation amount than adjusting 12${\sim}$14. Judging from the result, it should be considered that the optimum conditions of composting with sewage sludges were seeding of 5% microorganism and adjusting 21${\sim}$22 of initial C/N ratio, $200ml/l\;{\cdot}\;min$. of air flow rate and 64${\sim}$65% of initial moisture contents.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.183-188
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• 1998

Changes of chemical and physical properties of the butchery waste compost were assessed when the wastepaper was used as a bulking agent (BP). Temperature of compost, with frequent turnover, was increased up to $83^{\circ}C$ even during the winter. Canon exchange capacity of the compost was increased with composting time, but pH, water content, total carbon, total nitrogen, C/N ratio and salt concentration were decreased to the extents showing a convergency. Heavy metal contents of BP-192 were lower than the standard criteria. Germination rate of cucumber seed, when BP-34 and BP-96 composts were applied more than 15 g, was under 40%, but those of BP-143 and BP-192 were 100%, irrespective of the amounts of compost used. The C/N ratio of the matured compost was 8.6. Results indicated that wastepaper might be employed as a bulking agent for butchery wastes composting.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.4
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• pp.424-429
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• 2010

To solve the problems with excessive accumulation of soil inorganic N and resulting saline soils from overuse of nitrogen fertilizer, the effect of sucrose application on decrease of soil inorganic N content and electrical conductivity (EC) was studied. Sucrose treatment greatly reduced ${NH_4}^+$-N content in soil. The amount of reduction was greater as the amount of sucrose treatment was increased. When ${NH_4}^+$-N content was reached the lowest point (about 10 mg $kg^{-1}$or lower), the C/N ratio, which determines the amount of sucrose treatment, was around 10 regardless of initial ${NH_4}^+$-N content. For the rate of ${NH_4}^+$-N reduction 15~36 hours was required to reduce the initial ${NH_4}^+$-N content to half, and 36~69 hours to lower ${NH_4}^+$-N content to the lowest point (about 10 mg $kg^{-1}$or lower). In addition, sucrose treatment greatly lowered ${NO_3}^-$-N content. In case of C/N ratio above 10, initial ${NO_3}^-$-N content of 348 mg $kg^{-1}$ was reduced to the lowest of 14~21 mg $kg^{-1}$. As for the rate of ${NO_3}^-$-N reduction by sucrose treatment, it took 36~60 hours for ${NO_3}^-$-N content to reach the lowest point for C/N ratio of 10 or higher, and it took 3 weeks, comparably longer time, for C/N ratio of 5. Lowering soil EC from sucrose treatment showed the same trend as ${NO_3}^-$-N content. As an important energy and carbon source for humankind, sugar should not be wasted and must be carefully applied to soil. In principle, the best way of preventing salt accumulation in soil is to optimize the fertilizer input. However, when over-fertilization should be dealt with, the sucrose treatment would be a possible and effective counter-measure to reduce overdosed nitrogen sources in soil.

• Journal of Mushroom
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• v.13 no.1
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• pp.68-73
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• 2015

Hypocrea disease is the most severe disease of oyster mushroom cultivation in Korea. Physiological and ecological studies were performed on the pathogens (Hypocrea spp.) to obtain basic information for developing the integrated disease management system. Fourteen isolates of Hypocrea were collected from oyster mushroom house in five areas. Pathogenic fungi causing disease of oyster mushroom were identified as Hypocrea sp. based on morphological characteristics and pathogenicity. Two isolates (H-1, H-12) showed the fastest growth at $15^{\circ}C$ but four isolates (H-8, H-9, H-13, H-14) showed slower growth than those of other isolates at $20^{\circ}C$ and $25^{\circ}C$. Stroma with ascocarps and ascospore were produced on PDA under fluorescent light. The five isolates produced stroma with ascocarps and ascospores. Formation of fruiting body of strains H-14 of Hypocrea were the best out of all the strains on the potato dextrose agar (PDA). Also, fruiting bodies and ascospores were completely produced under fluorescent light. The growth of the isolates was correlated with total carbon content. The stroma of the isolates was formed mainly in histidine and asparagine treatment and especially in histidine-70 and asparagine-100 treatment. In the test of pathogenicity, after and before spawning showed very fast incidence of disease.

• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.51-55
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• 2002

Green peppers (Capsicum annuum L. cv, Soonjung) were grown under different combinations of $CO_2$ concentration and temperature levels and examined on the effect of elevated $CO_2$ and temeprature on plant growth, carbon and nitrogen concentrations. Plant height was stimulated by elevated $CO_2$ levels at 20.3 and 22.6$^{\circ}C$. Leaf area and fresh weight were remarkedly increased by high $CO_2$ concentration at 22.6$^{\circ}C$. Dry weights of leaf, stem, root, and whole plant were increased as temperature increased at 611 ppm $CO_2$, but those values decreased at 22.6$^{\circ}C$ in 397 ppm $CO_2$ concentration. Elevated $CO_2$ increased plant growth by 1.5 times at 20.5$^{\circ}C$ and 22.6$^{\circ}C$. C/N ratio increased with increasing temperature under elevated $CO_2$ levels.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.3
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• pp.223-227
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• 1983

This study was conducted to investigate the effect of supplement of Zeolite mineral whose C.E.C. is high, on the nutrients content in the compost and changes of compost status during its stacking period in 1982. The results obtained were summarized as follows : 1. By the supplement of Zeolite, the decomposing temperature in the compost was tended to be continued higher rather than that of nonsupplemented plot. 2. The contents of $NH_4-N$, $P_2O_5$, and $SiO_2$ in the compost were conspicuously increased by the supplement of Zeolite, poultry manure and urea etc, during the stacking period. It was considered that the supplement of Zeolite was much effective on the prevention of the waste of nutrients in the compost because the nutrients content was shown much high along with the progress of decomposition. 3. It was accepted to be the effect of Zeolite on shortening the period of compost decomposition and the prevention of the waste of nutrients content because the C/N ratio of the compost plots to supplement with the mixture of poultry manure, urea and Zeolite were 21.7 - 25.0 at 30 days after stacking but its of non-Zeolite treated plots were 21.3 - 24.8 at 60 days after stacking. 4. The C/N ratio in the compost and decrease rate of compost volume at 90 days after stacking was found to be significantly negative correlation.