• 한국초지조사료학회지
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• 제42권1호
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• pp.47-53
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• 2022

The objective of this study was to verify the effect of pig slurry application with acidification and biochar on feed value, nitrogen use efficiency (NUE) of maize forage, and ammonia (NH₃) emission. The four treatments were applied: 1) non-pig slurry (only water as a control, C), 2) only pig slurry application (P), 3) acidified pig slurry application (AP), 4) acidified pig slurry application with biochar (APB). The pig slurry and biochar were applied at a rate of 150 kg N ha^-1 and 300 kg ha^-1, respectively. The AP and APB treatments enhanced all feed values compared to C and P treatments. The NUE for plant N was significantly increased 92.1% by AP and APB treatment, respectively, compared to the P treatment. On the other hand, feed values were not significantly different between AP and APB treatments. The acidification treatment with/without biochar significantly mitigated NH₃ emission compared to the P treatment. The cumulative NH₃ emission throughout the period of measurement decreased by 71.4% and 74.8% in the AP and APB treatments. Also, APB treatment reduced ammonia emission by 11.9% compared to AP treatment. The present study clearly showed that acidification and biochar can reduce ammonia emission from pig slurry application, and pig slurry application with acidification and biochar exhibited potential effects in feed value, NUE, and reducing N losses from pig slurry application through reduction of NH₃ emission.

• 한국토양비료학회지
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• 제33권6호
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• pp.384-392
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• 2000

토양중 질산태 질소 함량이 $14{\sim}225mg\;kg^{-1}$의 범위를 갖는 시설재배지 9개 토양에서 배추를 공시작물로 하여 무비구, 3요소 표준시비량의 50%구, 100%구 및 150%구의 4개 시비수준에서 포트재배로 수량반응, 비료효과 및 시비효율 등을 검토하였다. 무비구 배추 건물중과 토양의 질산태 질소 함량은 유의성 있는 정의 상관을 나타냈고 시비구와 무비구의 건물중, 질소흡수량 및 질산태 질소흡수량의 차이로 평가한 비료효과 및 시비효율과는 유의성 있는 부의 상관을 보였다. 질산태 질소함량에 따른 시비수준별 건물중 반응의 관계로부터 표준시비량이 적용되는 질산태 질소의 하한기준은 $50mg\;kg^{-1}$ 미만으로 추정되었고, 질산태질소 함량과 비료효과 및 시비효율과의 회귀관계로부터 평가된 무비 재배를 위한 질산태 질소 함량은 $200mg\;kg^{-1}$ 이상으로 추정되었다. 따라서 시설재배지 토양중 질산태 질소 함량 $50mg\;kg^{-1}$에서 $200mg\;kg^{-1}$ 범위는 질소 표준시비량에 대한 비율로서 추천식은 $Y=-0.6667{\chi}+133.33$ 이었다 (Y:질소 표준시비량에 대한 %, ${\chi}$: 시험전 토양의 $NO_3-Nmg\;kg^{-1}$).

• 한국물환경학회지
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• 제36권5호
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• pp.405-422
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• 2020

Land use change by urbanization has significantly affected the hydrological process including the runoff characteristics. Due to this situation, it has been becoming more complicated to manage non-point source pollutions caused by rainfall. In order to effectively control non-point sources, it is necessary to identify the reduction efficiency of the various management method based on land use characteristics. Thus, the purpose of this study is to analyze the reduction efficiency of non-point source pollution management practices targeting three different watersheds with the different land use characteristics using the Soil and Water Assessment Tool (SWAT). To do this, the vulnerable subwatersheds to non-point source pollution occurrence within each watershed were selected based on the streamflow and water quality simulation results. Then, considering the land use, low impact development (LID) or best management practices (BMPs) were applied to the selected subwatersheds and the efficiency of each management was analyzed. As a result of analysis of the non-point source pollution reduction efficiency, when LID was applied to urban areas, the average reduction efficiencies of SS, NO₃-N, and TP were 5.92%, 4.62%, and 10.35%, respectively. When BMPs were applied to rural areas, the average reduction efficiencies of SS, TN and TP were 35.45%, 4.37%, and 10.16%, respectively. The results of this study can be used as a reference for determining appropriate management methods for non-point source pollution in urban, rural, and complex watersheds.

• 한국정밀공학회지
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• 제20권10호
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• pp.169-176
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• 2003

Genetic algorithm (GA), which has a powerful searching ability and is comparatively easy to use and also to apply, is in the spotlight in the field of the optimization for mechanical systems these days. However, it also contains some problems of slow convergence and low efficiency caused by a huge amount of repetitive computation. To improve the processing efficiency of repetitive computation, some papers have proposed paralleled GA these days. There are some cases that mention the use of gray code or suggest using gray code partially in GA to raise its slow convergence. Gray code is an encoding of numbers so that adjacent numbers have a single digit differing by 1. A binary gray code with n digits corresponds to a hamiltonian path on an n-dimensional hypercube (including direction reversals). The term gray code is open used to refer to a reflected code, or more specifically still, the binary reflected gray code. However, according to proposed reports, gray code GA has lower convergence about 10-20% comparing with binary code GA without presenting any results. This study proposes new Full gray code GA (FGGA) applying a gray code throughout all basic operation fields of GA, which has a good data processing ability to improve the slow convergence of binary code GA.

• 한국토양비료학회지
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• 제50권6호
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• pp.574-587
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• 2017

Excessive application of nitrogen (N) fertilizer to support switchgrass growth for bioenergy production may cause adverse environmental effects. The objective of this study was to determine optimum N application rate to increase biomass yield of switchgrass and to reduce adverse environmental effects related to N. Switchgrass was planted in May 2008 and biomass yield, N uses of switchgrass, nitrate ($NO_3$) leaching, and nitrous oxide ($N_2O$) emission were evaluated from 2010 through 2011. Total N removal significantly increased with N rate despite the fact that yield did not increased with above $56kg\;N\;ha^{-1}$ of N rate. Apparent nitrogen recoveries were 4.81 and 5.48% at 56 and $112kg\;N\;ha^{-1}$ of N rate, respectively. Nitrogen use efficiency decreased into half with increasing N rate from 56 to $112kg\;N\;ha^{-1}$. Nitrate leaching and $N_2O$ emission were related to N use of switchgrass. There was no significant difference of cumulative $NO_3$ leaching between 0 and $56kg\;N\;ha^{-1}$ but, it significantly increased at $112kg\;N\;ha^{-1}$. There was no significant difference of cumulative $N_2O$ emission among N rates in crest, but it significantly increased at $112kg\;N\;ha^{-1}$ in toe. Excessive N application rate (above $56kg\;N\;ha^{-1}$) beyond plant requirement could accelerate $NO_3$ leaching and $N_2O$ emission in switchgrass field. Overall, $56kg\;N\;ha^{-1}$ might be optimum N application rate in reducing economic waste on N fertilizer and adverse environmental impacts.

• 한국토양비료학회지
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• 제49권5호
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• pp.531-540
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• 2016

The adoption of legume cover crops in no-tillage system can contribute to improve soil fertility by providing several benefits, including reduction in soil erosion, suppression of weed growth and N supply to subsequent crops. We conducted a field study to investigate the effect of cover crops and nitrogen fertilization rates on yield and nitrogen use efficiency of waxy corn (Zea mays L.) in no-tillage upland field. Two legume cover crops, hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnuturn L.) were mechanically terminated with roller in early June. For each cover crop treatment, nitrogen (N) fertilizer was applied at three different rates (145, 72.5 and $0kg\;N\;ha^{-1}$). The growth and yield characteristics of corn were significantly affected by the N fertilization rates in crimson clover plots, which suggest N mineralization from the cover crop residue was not sufficient. In contrast, N fertilization rates had no significant effect on growth and yield of corn in hairy vetch plots, indicating that the amount of N released from the cover crop is large enough to meet most of the N requirement of corn. However, the application of N fertilizer in hairy vetch cover plots resulted in slight increase of crop yield, though not statically significant, and high levels of N concentration in corn plant tissue possibly due to luxury consumption of N. Organic residues on the soil surface in hairy vetch cover plots had substantial amounts of N after harvest, ranging from 100 to $116kg\;N\;ha^{-1}$, which is presumably retained during winter season and released by microbial mineralization in subsequent year. The highest nitrogen yield efficiency was achieved in the plot with hairy vetch cover and no N fertilizer application, followed by the plot with hairy vetch cover and $72.5kg\;N\;ha^{-1}$ fertilization rate. In conclusion, hairy vetch showed better performance in corn productivity as compared with crimson clover. In addition, it was concluded that the application of N fertilizer between 0 and $72.5kg\;N\;ha^{-1}$ in combination with hairy vetch cover crop might be most efficient for corn yield under no-tillage system with climatic and soil characteristics similar to those of the experimental site.

• Asian-Australasian Journal of Animal Sciences
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• 제13권7호
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• pp.995-1002
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• 2000

To evaluate energy efficiency and partition of nutrients, 32 piglets were weaned at 14 d of age and individually fed diets containing 15% fat from coconut oil (CO, medium chain saturated), high oleate sunflower oil (HOSO, n-9 series), soybean oil (SO, n-6 series), or linseed oil plus fish oil, (LF, n-3 series). After 4 weeks, the subjects were sacrificed to evaluate empty body composition and apparent ileal digestibility with the slaughter method. No statistical effect of dietary fat sources on growth was observed. The digestibility of fat from the coconut oil diet was higher than fats from the diets containing high levels of unsaturated fatty acids. The efficiency of use of metabolizable energy for growth averaged 63% and was not affected by the diet. Dietary fat composition was reflected strongly in backfat. Total body neutral and polar fatty acids were influenced too. For the whole body phospholipid fraction the ratio of n-6 to n-3 and the double bond index were 4.3, 5.8, 7.2, 0.78 and 69, 87, 89, 87 for CO, HOSO, SO, and LF respectively. These results show that for the coconut oil diet the degree of unsaturation of phospholipids in the body was lower and that, in the other diets, it did not differ, but double bond index was maintained with different n-6 to n-3 ratios in carcass fat. On the whole the data on body fat composition indicate that the dietary fat tended to be deposited in similar quantity in the body, whatever was the dietary fatty acid profile.

• 한국토양비료학회지
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• 제48권1호
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• pp.44-49
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• 2015

Urea has been the most useful N-source, due to lower cost per unit of N. But nitrogen use efficiency of urea may be reduced because of losses from agricultural system by volatilization of ammonia to atmosphere. This study was conducted to evaluate the nitrogen efficiency and growth of hot pepper (Capsicum annuum L.) by mixed treatment with nitrogen and zeolite. They were treated with N $161kg\;ha^{-1}$, N $230kg\;ha^{-1}$, nitrogenzeolite mixture (NZM) $161kg\;ha^{-1}$, NZM $230kg\;ha^{-1}$ and N $0kg\;ha^{-1}$, respectively. In the soil chemical properties after experiment, soil pH decreased but available $P_2O_5$, EC and total nitrogen increased in nitrogen-zeolite mixture treatment. $NO_3-N$ content in the soil showed the highest level in NZM $230kg\;ha^{-1}$. NZM $161kg\;ha^{-1}$ treatment increased growth and yield of hot pepper compared to urea alone. Nitrogen utilization efficiency of hot pepper plant was 47.15% at the treatment of NZM $161kg\;ha^{-1}$, while 36.74% at N $230kg\;ha^{-1}$. These results showed that application of mixture of nitrogen and zeolite had positive influence to improve the efficiency of nitrogen utilization and increase of red pepper yield.

• 한국토양비료학회지
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• 제32권2호
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• pp.140-146
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• 1999

본 연구(硏究)는 2년간('97~'98) 이상고온(異常高溫)해에 벼 어린모 기계이앙비재배시(機繼移秧秘栽培時) 완효성비료(緩效性肥料)(LCU)의 시용(施用)에 따른 시비질소(施肥室素)의 토양중(土壤中) $NH_4-N$ 발현량(發現量), 질소흡수량(室素吸收量) 및 이용율(利用率), 수량성(收量性) 변이(變異)를 조사하기 위하여 호남평야지(湖南平野地) 논토양의 대표토양(代表土壤)인 전북통(全北統)에서 시험한 결과로 다음과 같이 요약할 수 있다. 시비질소(施肥窒素)의 용출(溶出)은 완효성비료(緩效性肥料)의 기비전량(基肥全量) 전층시비시(全層施肥時) 이앙후(移秧後) 50일인 최고분벽기(最高分蘗期)에 거의 완료(完了)되었으며 최고발현기(最高發現期)는 무효분벽기(無效分蘗期)였다. 또 관행(慣行)의 표층시비(表層施肥)에서는 전기간 $NH_4-N$함량(含量)이 낮았다. 완효성비료(緩效性肥料) 시용구(施用區)의 출수기(出穗期) 비절현상(肥切現象)은 SPAD 31.6에서 나타났으며 경엽(莖葉)중 질소농도(窒素濃度)는 1.29%였다. 시비질소(施肥室素) 필요량(必要量)은 출수기(出穗期)~성숙기(成熟期)까지 관행(慣行)은 $2.9kg\;ha^{-1}$였으나 완효성비료(緩效性肥料)의 기비전량(基肥全量) 전층시비구(全層施肥區)에서는 $11.9kg\;ha^{-1}$로 많았다. 질소이용율(窒素利用率)은 관행(慣行)에 비하여 완효성비료(緩效性肥料) 시용구(施用區)에서 높았고 수비(穗肥)를 시용(施用)하므로서 12.7%가 더 증가(增加)되었다. 쌀수량(收量)은 완효성비료(緩效性肥料)를 기비(基肥)로만 시용(施用)한 것에 비하여 수비(穗肥)를 시용(施用)하므로서 13%의 증수(增收)를 보였다.

• Environmental Engineering Research
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• 제11권4호
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• pp.208-216
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• 2006

In order to create a single flocculant/dual flocculation system, polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride (TAEAC) polymers with varying molecular weights and structures were prepared for use of flocculants. The higher the cationic density of the polymer is higher, the higher was the conversion rate and the ratio of monomer. An acrylamide as nonionic monomer was less reactive than a TAEAC as cationic monomer. The branched polymer which was polymerized with a cross-linking agent, N, N-methylene bis-acrylamide had a higher stability and higher viscosity than a linear polymer but its dewatering efficiency was poor in a single flocculation system. In the case of single flocculant/dual flocculation, the branched polymer has better flocculation efficiency and the water content of the dewatered cakes was lower than the others, as the result of a re-flocculation effect. The optimum conditions for dual flocculation are a sequence in which the $1^{st}$ and $2^{nd}$ dosage are 75% and 25%/total dosage of a single flocculation system. The dewatering efficiency of a dual flocculation system is improved considerably from 10 to 25% under the experimental conditions used herein.