• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.53-53
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• 2022

Modem agricultural production needs to provide sustainable management practices that are eco-friendly and low cost. Plant extracts are a cost-effective and environmentally friendly alternative to synthetic plant growth regulators. This study was therefore carried out to investigate the effects of various plant extracts produced using different extraction methods on the vegetative growth of rice under laboratory and greenhouse conditions. For this study, seventeen plant extracts were made from plant species such as leaves of M. arvense, C. asiatica, M. oleifera, V. radiata, V. unguiculate, P. guajava, A. vera, and A. tuberosum, aboveground plant parts of C. rotundus, M. sativa, and P. frutescens, roots of R. undulatum, tubers of A. sativum, leaves and stems of G. max (cv. Taegwang) as well as rice straw and hulls (cv. Hopyeong). As a test crop, we applied these extracts to rice plants. For the purpose of making our extracts, some plant materials and species were collected in fields and others were purchased from Chonnam Hanyaknonghyup Cooperation (South Korea). Leaves, roots, and aboveground plant parts of plant species were dried, ground, extracted (water, boiling water and ethanol) and fermented. Rice growth promotion effects were determined using plant extracts at 0, 0.05, 0.1, 0.5, and 1% concentrations under petri dish conditions. Seven selected plant extracts were applied to rice seeds with soil drench application or seedling at 3-4 leaf stages with soil and foliar applications under greenhouse conditions. For comparison with extracts, we used urea at 0.6%. Of the 17 water extracts used in this study, 10 extracts reduced rice growth, but the other 7 extracts (P. guajava, A. vera, A. tuberosum, M. sativa, A. sativum, and G. max) increased growth by 40-60% on compared to the control in Petri dish bioassay. Thus, these 7 extracts were selected for further study. Under greenhouse conditions, rice growth also increased by 20-40% when the same 7 extracts were applied to rice seeds using soil drench application. Furthermore, at the 3-4 leaf stage rice growth also increased 30-80% or 30-60% when the same 7 extracts were applied using soil and foliar applications. Overall, the 7 extracts produced higher rates of growth promotion when soil drench application was used than when foliar application was used. In the case of boiling water and ethanol extracts, rice growth increased only 20% in response to both soil drench and foliar application of the same 7 extracts. Rice growth promotion was greater when extracts were produced using water extraction method than boiling water and ethanol extraction methods. Most notably, the 7 water extracts used in this study produced higher rates of growth promotion than urea at 0.6% which is typically used for crop growth promotion. Overall, the 7 water extracts when applied using soil drenching method can be used as effective growth promotors of rice in organic agriculture.

• 한국응용과학기술학회지
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• 제19권3호
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• pp.213-221
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• 2002

Activated carbons with high surface area of 2,600 $m^{2}/g$ and high pore volume of 1.2 cc/g could be prepared by KOH activation of rice hulls at a KOH:char ratio of 4:1 and $850^{\circ}C$. In order to increase the adsorption capacity of hydrogen sulfide, which is one of the major malodorous component in the waste water treatment process, various contents of $Na_{2}CO_{3}$ and $KIO_{3}$ were impregnated to the rice-hull activated carbon. The impregnated activated carbon with 5 wt.% of $Na_{2}CO_{3}$ showed improved $H_{2}S$ adsorption capacity of 75 mg/g which is twice of that for the activated carbon without impregnation and the impregnated activated carbon with 2.4 wt.% of $KIO_{3}$ showed even higher $H_{2}S$ adsorption capacity of 97 mg/g. The improvement of $H_{2}S$ adsorption capacity by the introduction of those chemicals could be due to the $H_{2}S$ oxidation and chemical reaction with impregnated materials in addition to the physical adsorption of activated carbon.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권6호
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• pp.82-94
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• 2021

Facilities for low impact development (LID) or groundwater recharge have the high potential spreading groundwater nitrate contamination because of the rapid infiltration. This study was initiated to remove nitrate from the waters using agricultural byproducts as organic sources for denitrification during infiltration. As the first step of this purpose, we experimentally tested the denitrifying efficiency of 4 organic materials (pine tree woodchips, cherry leaves, rice straws, and rice hulls) and tried to identify the key factors controlling the efficiency. For this study, we precisely investigated the change of chemical reactions during the experiment by analyzing various geochemical parameters. The result shows that the denitrification efficiency is not simply linked to the availability of the easily decomposable contents in the organic matter. It is found that avoiding the severe pH decrease due to the CO₂ generation is the essence to derive the efficient denitrifying conditions when organic matters were used.

• Asian-Australasian Journal of Animal Sciences
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• 제33권8호
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• pp.1323-1331
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• 2020

Objective: Three types of dietary fiber were fed to sows during gestation and lactation stages to monitor their physiological and metabolic adaptations during the pre-partum period and to determine how these effects may influence the lactation period and sow performance. Methods: Soon after breeding, 54 sows were selected and were fed with 20% supplementation as fed of wheat bran (WB), soya hulls (SH), or rice hulls (RH) in diets during gestation and lactation. Sows were weighed, backfat thickness was measured ultrasonically and jugular blood samples were collected from all sows. The litter size was equalized to 10, by fostering piglets from sows on the same treatment. Results: Sows gained 22.0, 21.8, and 25.5 kg of net maternal body weight during gestation (for WB, SH, and RH sows, respectively; p = 0.007). There was no treatment effect on the body weight change during lactation (p = 0.158), however RH sows consumed an average of 133.66 kg of feed, WB sows took 121.29 kg and SH sows took 126.77 kg during lactation (p<0.001). The SH litters gained an average of 59.34 kg of weight during lactation, while other litters gained 51.58 and 49.98 kg (for WB and RH litters, respectively; p<0.001). Exception for aspartate aminotransferase and alanine aminotransferase, measured serum biochemical values were broadly in agreement with earlier reports. Despite the use of additional vegetable oil to balance the energy level, RH sows still had lower concentrations of serum triglycerides in late gestation. Conclusion: Different types of fibrous ingredients in the gestation diet influenced most of the investigated reference values for sows. The values of serum biochemical parameters were generally not affected by fiber type during the lactation stage. The SH supplementation for sows is an effective approach to give heavier litters at birth and weaning and to increase voluntary feed intake in early lactation.

• 한국농공학회지
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• 제41권2호
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• pp.55-60
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• 1999

퇴비호 과정중에 암모니아 휘산은 퇴비 내의 질소성분을 유출시키고 있는 동시에 악취를 발생한다는 측면에서 바람직하지 못하다. 아직까지 암모니아 휘산을 방지할 수 있는 방법은 개발되어 있지 않다. 본 연구에서는 퇴비화 과정에서 온도, 암모니아휘산및 엔탈피의 변화를 분석하였다. 퇴비화 온도가 높을 때는 암모니아 휘산도 많이 발생하였으나 퇴비화 15일 후 온도가 63$^{\circ}C$로 하강함에 따라 암모니아 휘산은 줄어들기 시작하여 온도가 6$0^{\circ}C$이하로 떨어지는 21일부터는 거의 발생하지 않았다. 퇴비화 온도에 의하여 진행과정과 암모니아 휘산의 추이를 추정할 수있었다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.431-434
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• 2001

This study was carried oui to investigate tile filtering performance of using fresh compost as a biofilter. Three biofilter vessels were made using fresh compost as a biofilter media. A mixtures of dairy manure, soy sludge, rice hulls and sawdust were composted in a pilot scale reactor of 605L to generate tile ammonia emission. The ammonia emission from the compost reactor was passed through three biofilters and collected in the boric acid trap to measure the ammonia emission. Filtering performance was influenced by the depth of biofilter media. Efficient filtering effect was acquired for the depth above 40 cm.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.685-691
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• 1996

Recent research in composting greenhouse has focused on some of the fundamental properties during the process such as temperature , carbon dioxide content and odors which change as the composting progresses. The composting greenhouse of cattle manure with rice hulls by a forced aeration method without turning is available for the practical proposition. The control of a predetermined temperature range(45-65$^{\circ}C$) is possible if intermittent aeration is used. The carbon dioxide concentration was maintained in the range from 400 to 2650 ppm by the intermittent aeration. The ammonia emission rose rapidly leading to a temperature increase of composting material up to more than 60$^{\circ}C$ for six days. Ammonia emission declined quickly and could hardly be detected after 10 days of running period.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.405-410
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• 1999

This study was performed to find the recycling performance and to provide design data during recycle solid composting system to reduce bulking agent cost, Dairy manure amended with rice hulls and recycled compost was composted in a laboratory -scale vessel by continuous aeration for 10 days. The temperature and ammonia emission variations according to the ratios of bulking agents during the primary aeration stage were surveyed. Also, the influence of fresh compost quality on the recycling performance were anlayzed. While recycled composting system were operatured. The temperature in compost was maintained in the range of 40∼60$^{\circ}C$ needed for biodegradation and death of pathogenic organisms, but the ammonia emission was different by the ratios of recycled compost. The ammonia emission increased due to the low C/N ratio(17.6), high pH value(8.1) of the recycled compost.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2001년도 가을 학술발표회 논문집
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• pp.303-305
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• 2001

Porous carbons have beef used as adsorbents, filters, catalyst supports, etc. due to well-development pore structure. Porous carbons can be prepared by two different activation processes i.e. physical activation by steam or CO$_2$, and chemical activation by KOH, H$_3$PO$_4$ etc. from various raw material. Recently, agricultural wastes such as rice hulls [1], coconut shell [2-31 and straws [4] are growing interest as precursors fur porous carbons due to its easy availability and cheapness. (omitted)

• 한국토양비료학회지
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• 제44권1호
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• pp.1-7
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• 2011

Application of biochar to soils is proposed as a significant, long-term, sink for atmospheric carbon dioxide in terrestrial ecosystems. In addition to reducing emissions and increasing the sequestration of carbon, production of biochar and its application to soils will contribute improve soil quality and crop productivity. Objectives were i) to evaluate biochar productivity from crop residues using a low-cost field scale mobile pyrolyzer and ii) to evaluate characteristics of feedstocks and biochars from locally collected crop residues. Pyrolysis experiments were performed in a reactor operated at $400-500^{\circ}C$ for 3-4 hours using biomass samples of post-harvest residues of corn (Zea mays L.), cotton (Gossypium spp.), rice (Oryza sativa L.), sorghum (Sorghum bicolor L.) and wheat (Triticum aestivum L.). Feedstocks differed, but average conversion to biochar was 23%. Carbon content of biomass feedstock and biochar samples were 445 g $kg^{-1}$ and 597 g $kg^{-1}$, respectively. Total carbon content of biochar samples was 34% higher than its feedstock samples. Significant increases were found in P, K, Ca, Mg, and micro-nutrients contents between feedstock and biochar samples. Biochar from corn stems and rice hulls can sequester by 60% and 49% of the initial carbon input into biochar respectively when biochar is incorporated into the soils. Pyrolysis conversion of corn and rice residues sequestered significant amounts of carbon as biochar which has further environmental and production benefits when applied to soils. Field experiment with crop residue biochar will be investigated the stability of biochars to show long-term carbon sequestration and environmental influences to the cropping systems.