• Asian-Australasian Journal of Animal Sciences
• /
• 제30권5호
• /
• pp.660-665
• /
• 2017

Objective: The objective of the study was to determine the effects of increasing levels of metabolizable protein (MP) on lactation performance and nitrogen (N) efficiencies in lactating dairy cows. Methods: Nine multiparous cows in mid lactation [$113{\pm}25$ days in milk] received three treatments in a $3{\times}3$ Latin square design with a period length of 21 days. The treatments were three diets, designed to provide similar energy and increasing supply of MP (g/d) (2,371 [low], 2,561 [medium], and 2,711 [high] with corresponding crude protein levels [%]) 15.2, 18.4, and 20.9, respectively. Results: Increasing MP supplies did not modify dry matter intake, however, it increased milk protein, fat, and lactose yield linearly. Similarly, fat corrected milk increased linearly (9.3%) due to an increase in both milk yield (5.2%) and milk fat content (7.8%). No effects were observed on milk protein and lactose contents across the treatments. Milk nitrogen efficiency (MNE) decreased from 0.26 to 0.20; whereas, the metabolic efficiency of MP decreased from 0.70 to 0.60 in low to high MP supplies, respectively. The concentration of blood urea nitrogen (BUN) increased linearly in response to increasing MP supplies. Conclusion: Increasing MP supplies resulted in increased milk protein yield; however, a higher BUN and low MNE indicated an efficient utilization of dietary protein at low MP supplies.

• 한국환경보건학회지
• /
• 제23권1호
• /
• pp.95-104
• /
• 1997

The objectives of this study are to investigate the effect of media on the removal efficiency of nitrate-nitrogen and the biofilm thickness in the fluidized bed biofilm reactor(FBBR) used for the high rate denitrification of nitric acid wastewater. Granular activated carbon(GAC) of 1.274 mm diameter and sand of 0.455 mm diameter were used as the media in the FBBR of 0.05 m diameter and 1.5 m height. As the nitrate-nitrogen concentration of the influent was increased stepwise from 600 to 4800 mg/l, the nitrate- and nitrite-nitrogen concentration of the effluent, biofilm thickness and biofilm dry density were measured to study the effects of media on the denitrification efficiency. The biofilm thickness increased with the substrate loading rate, and the biofilm dry density decreased with the increase of the biofilm thickness. At the influent nitrate-nitrogen concentration of 2400 mg/l, the removal efficiency in the FBBR with GAC was 88%, while that in the FBBR with sand was 99.6%. The biofilm in the FBBR with GAC was so thick, 754.9 $\mu$m, as to increase the mass transfer resistance, compared to that, 143.7 $\mu$m, in the FBBR with sand. The maximum specific denitrification rate in the FBBR with GAC was 15.0 kg-N/m$^3\cdot$ day, while that in the FBBR with sand was 18.0 kg-N/m$^3\cdot$ day. The biomass concentration in the FBBR with sand exhibited the high value 37 kg/m$^3$.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권12호
• /
• pp.1777-1781
• /
• 2003

The lysine requirements of juvenile yellowtail flounder (Pleuronectes ferrugineus) having 19.5 g initial body weight were estimated by feeding six practical-type diets containing graded levels of lysine (1.21 to 2.69% of dry diet). Dietary amino acid profile simulated that of whole body of yellowtail flounder. Most of amino acids in the diets were provided by corn gluten meal, herring meal and gelatin. Protein efficiency ratio (PER) improved significantly until lysine level increased up to 2.1% (4.3% of protein). Same trend was observed in feed:gain ratio (FGR) which maintained constant in fish groups fed diets containing lysine above 2.1%. The highest nitrogen gain (0.34 g/fish) in whole body was found in fish fed 2.1% lysine, though the value was not different from those of fish fed above the level of lysine. Fish fed 2.1% lysine also showed the best nitrogen retention efficiency of 24.6%. The broken-line analysis of protein efficiency ratio and body nitrogen gain against dietary lysine level yielded an estimated lysine requirement of 2.2% (4.5% of protein) and 2.3% (4.7% of protein), respectively.

• 한국환경과학회지
• /
• 제6권4호
• /
• pp.409-415
• /
• 1997

In order to Investigate the possibility as a simple technique of wastewater treatment for recirculating aquaculture system, the experiment by a biofilter unfit was carried out. The high and stable removal efficiency of nitrogen could be obtained by selecting the optimum recycle ratio and DO concentration. It was found that the proper combination of nitrifacation and denitrfication step in the reactor would be required for increasing the removal efficiency. The extent of nitrogen removal gradually decreased UO the rise of re- cycle ratio since the depression of denitrificatlon by the lack of hydrogen donor. The depression of nitrogen removal was overcome by increasing the CIN ratio In the wastewater. The extent of phosphorus removal was increased slightly with the increase of DO concentration and recycle ratio, but high removal efficiency was not observed. However, the extent of COD removal was not affected by recycle ratio and DO concentration and showed the stable removal of above 90%.

• 한국농공학회지
• /
• 제44권2호
• /
• pp.161-173
• /
• 2002

Recently, absorbent biofilters, which are inexpensive and easy to manacle, have been supplied to the rural areas, but have limitations in removing the nutrients effectively. Accordingly, as an alternative plan. natural zeolites were arranged in front or at the rear of the absorbent biofilters, and their removal efficiency for nitrogen and, ultimately, their applicability to the on-site wastewater treatment system were studied. Furthermore, the same experiments were carried out on artificial zeolites, made from coal ashes at National Honam Agricultural Experiment Station, to compare natural zeolites with artificial ones. Treated wastewater through the Absorbent Biofilter showed 22.6% nitrogen removal efficiency, while 64.6% was attained when natural Zeolites were placed in front of the absorbent biofilters (Zeolite-Aerobic process). As an addition, phosphorus was also efficiently removed. On the other hand, Aerobic-Zeolite process, which arranged natural zeolites at the rear of the biofilters, did not have significantly higher nitrogen removal as compared to the treatment using only the absorbent biofilters. Furthermore, upon regeneration of the natural zeolite, the ion exchange rate was fecund to increase over 10% as compared to before regeneration. Our results show that natural zeolites, applied to the on-site wastewater treatment system through the Zeolite-Aerobic process, not only increase the removal efficiency of nutrients, but, by choosing the appropriate regeneration time, can also be cast-effective. Artificial zeolites, on the other hand, though more efficient in removing nutrients, cannot be regenerated and, therefore, are not cost-effective.

• 플랜트 저널
• /
• 제15권2호
• /
• pp.46-55
• /
• 2019

기존 메탄 & 질소 팽창 사이클의 효율 개선을 위해 2개의 메탄 팽창 공정 (cold composite curve에 변곡점을 하나 더 추가하기 위해 warm & cold 2개 공정으로 나눔)과 1개의 질소 팽창 공정을 사용한 천연가스 액화 사이클을 소개하기 위한 논문이다. 이전 질소 팽창 사이클 및 메탄 & 질소 사이클과 비교했을 때, 13.92 및 13.13에서 12.08 kW/ton/day로 효율이 8~15% 정도 개선되었다. 순 현재가치(NPV) 기준으로 한 수명 주기 비용 분석(LCC analysis) 또한 약간의 CAPEX 증가는 있지만 프로젝트 순 현재가치가 개선된 결과를 보여준다.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2004년도 춘계 학술대회지
• /
• pp.102-103
• /
• 2004

[ $\bigcirc$ ] In the growth simulation without changing of module with ORYZA2000, dry matter, LAI and leaf nitrogen content(FNLV) were estimated well under high nitrogen applicated condition, but overestimated under low nitrogen applicated condition. $\bigcirc$ Nitrogen stress factor on the SLA was introduced into ORYZA2000 because especially overestimated LAI under low nitrogen applicated condition was originated from SLA decrease with leaf nitrogen(FNLV) decrease. $\bigcirc$ In the growth simulation with modified SLA modified module, LAI was estimated well under even low nitrogen applicated condition, but dry matter was hardly changed compared with default. $\bigcirc$ Simulated plant nitrogen content and dry matter have no clear difference between modules, but compared with observed values, panicle weight(WSO) and rough rice yield(WRR14) were overestimated under high nitrogen applicated because of lodging, pest, disease and low nitrogen use efficiency.

• Weed & Turfgrass Science
• /
• 제3권2호
• /
• pp.137-142
• /
• 2014

본 연구는 규산질 비료와 질소 비료 혼용이 한국잔디의 생육과 질소비료 효율에 미치는 영향을 알아보기 위해 수행하였다. 한국잔디의 초장, 지상부, 포복경과 지하부의 생체중과 건물중, 지상부 개체수, 포복경 길이는 규산질 비료 400 kg/10a와 질소비료 24 kg/10a을 혼합시비 하였을 때 질소비료의 24 kg/10a 단용처리구보다 증가하였고, 규산질 비료와 질소비료 18 kg/10a은 질소비료의 24 kg/10a 단용 처리구와 유의성이 없었다. 규산질 비료와 질소비료를 혼합하여 시비했을 경우 질소비료 약 25-30% 절감효과가 있는 것으로 판단되었으며, 토양 내 유효 규산과 유기물의 함량은 규산질 비료 시비를 하지 않은 것보다 시비를 하였을 때 더 높게 나타나 규산질 비료가 한국잔디의 생장과 밀도를 높였으며 토양의 화학적 특성에 중요한 요소로 작용하였다.

• Journal of Applied Biological Chemistry
• /
• 제65권1호
• /
• pp.1-6
• /
• 2022

요소는 가장 보편적인 질소비료 중 하나인데 빠른 가수분해와 환경으로의 질소 손실로 인해 작물에 질소 이용효율이 낮다. 따라서 요소 비료에서 질소 방출을 제어하는 것이 중요하다. 본 연구에서는 토양의 요소가수분해효소를 억제하여 요소에서 과도한 질소 용출을 방지하기 위해 목초액을 처리하였다. 목초액의 유효성분은 목초액을 처리하지 않은 토양에 비해 암모늄태 질소의 추출량을 79.7% 감소시켜 토양에서 요소의 암모니아화를 억제한 것으로 나타났다. 목초액이 요소의 시비 효율에 미치는 영향을 평가하기 위해 요소와 목초액을 처리한 토양에서 배추(Brassica campestris var. Pekinensis)를 각각 포트와 포장에서 재배하였다. 목초액을 요소와 같이 처리했을 때 관행적으로 사용하는 요소량의 반을 사용하였으며 관행과 비교하여 유사한 배추 생체중을 보였다. 배추의 질소 함량은 목초액 처리구에서 낮아 배추가 질소를 효율적으로 사용한 것으로 판단된다. 따라서 요소를 목초액의 유효성분과 같이 처리하면 시비량과 시비 횟수를 감소시킬 수 있다.

• 한국토양비료학회지
• /
• 제39권6호
• /
• pp.345-350
• /
• 2006

본 시험은 벼 종이멀칭이앙 시 적정한 완효성비료의 시용량을 구명하고자 경기도 수원에 위치한 작물과학원 벼 연구 포장 강서통에서 대안벼를 2004년 5월 28일에 중묘를 멀칭기계 이앙하였다. 시험에 사용한 완효성비료는 LCU (Latex Coated Urea, 21-7-9) 복비를 시용하였다. 피복재료는 생분해성 폴리에스터 (PES $10{\mu}m$)+재생지를 이용하여 피복하였다. 처리내용은 관행질소시비량 ($110kg\;ha^{-1}$)을 기준으로 하여 완효성비료호 기준시비량의 60%, 80%구, 100%구와 관행 및 무질소구를 두고 시험을 수행하였다. 벼 멀칭이앙 시 모의 결주율은 무피복의 관행이앙과 차이가 없었다. 잡초발생 및 방제가는 시비량이 적을수록 잡초가 다양해지고 잡초방제가가 낮아지는 경향이었다. 벼 이앙 후 일수가 진전됨에 따라서 시비량이 많을수록 초장와 경수가 크거나 많아지는 경향이었고 완효성비료 80%구의 벼 생육이 관행시비구와 차이가 없는 경향이었다. 엽색도와 토양 중 $NH_4{^+}-N$도 유사한 경향을 보였다. 따라서 수량구성요소 중 $m^2$당 이삭수의 증가로 인하여 완효성비료 80%구가 관행과 수량 차이가 없었다. 농업적 질소이용 효율은 시비량이 적을수록 증가하였다. 벼 종이멀칭이앙 시 벼 수량 및 수량구성요소, 잡초발생 및 방제가, 시비효율 등을 종합적으로 고려하여 관행질소 시비량의 80%를 완효성비료로 이앙 전에 밑거름으로 전층시비 하는 것이 알맞을 것으로 생각된다.