• 한국농공학회지
• /
• 제40권4호
• /
• pp.85-93
• /
• 1998

In the 2nd year study of a 5 year project to evaluate the soil quality and develop the best management practices for mountaineous soils, 11 runoff plots were treated and monitored with respect to physical property of the soil, runoff and sediment discharge, and the following results were obtained. 1. Bulk density and porosity did not show any siginificant difference between experimental treatments. 2. Runoff was basically dependent on the soil's physical property and tillage. Up-and-down plots showed the highest runoff while contour plots the lowest runoff. 3. Sediment yield in the mountaineous soils was directly related to tillage and residue cover. Residue covered plots showed the lowest sediment yield and up-and-down plots the highest sediment yield. And it is recommended that the best management practices using till_age and residue cover for the mountaineous soils must be developed to protect soil quality and maintain agricultural productivity.

• 한국분무공학회지
• /
• 제12권2호
• /
• pp.94-100
• /
• 2007

The liquid phase LPG injection (LPLi) system (the third generation technology) has been considered as one of the next generation fuel supply systems for LPG vehicles, since it has a very strong potential to accomplish the higher power, higher efficiency, and lower emission characteristics than the mixer type (the second generation technology) fuel supply system. To investigate the characteristics of LPG residue in liquid phase LPG injection system, various rubbers in LPG fuel system were reacted with LPG fuels during 3 months. The experimental results showed that the residue of a cover rubber in a fuel pump after test increased 10 times higher than that before test. Furthermore, the amount of sulfur, nitrogen species which are considered as main sources in deposit formation in the LPLi fuel injector were also found to be higher than that in original LPG fuel. And rubber properties of fuel pump cover were decreased after reaction test compared with those of the original rubber. Therefore, the rubber for fuel pump cover is not suitable for a proper material in LPLi fuel system. And these results can provide more information if a motor company shares the data of core rubber parts in field test LPLi vehicles.

• Journal of Applied Biological Chemistry
• /
• 제50권1호
• /
• pp.22-28
• /
• 2007

Most of the uplands in alpine regions during off-season are left as bare soil and thus vulnerable to severe erosion due to the inherent topographical conditions. Appropriate management strategy to cope with this problem is urgently needed, yet few researches have been reported on the effects of winter cover crop and management on soil erosion. We assessed effects of ryegrass (Lolium multiflorum) as cover crop, green manure or mulching residue on soil erosion and quality through field and segment plot lysimeter experiments in alpine uplands. Ryegrass successfully adopted to winter in alpine region based on biomass, nutrient contents, and vigors of top and root systems. Incorporation of ryegrass into soil maintained soil fertility, nutrient uptake, and yield of cabbage exerting potential use as green manure. Cultivation of ryegrass suppressed occurrence of Chinese cabbage pests. Surface coverage by ryegrass as cover crop and mulching residue significantly reduced soil loss up to 96%, when combined with soil conservation management practices. Results revealed maintaining cover crop over winter was beneficial in reducing soil erosion, and sustaining soil quality and Chinese cabbage productivity. This study suggested winter cover crop, followed by green manure and mulching, and conservation tillage system could be one of the best management practices in alpine sloping uplands cultivating Chinese cabbage.

• 한국환경농학회지
• /
• 제19권3호
• /
• pp.201-205
• /
• 2000

강원도 고랭지 경사 농경지에서의 유사량을 최소화하기 위한 최적영농방법 제안을 위하여 대관령 부근의 고령지 농업시험장의 작물포장을 선정,설치하였다. 가로 25m 세로 60m로 장방형 면적에 유출시험포 11개를 설치하고 경운방법, 지표피복 및 시비방법을 달리하며 3년동안 유사량을 조사하였다. 무경운에 100% 지표 피복 처리된 옥수수 시험포와 비닐로 멀칭한 감자 시험포에서 가장 작은 유사가 발생하였다. 최대의 유사는 등고선과 직각방향으로 경운한 시험포에서 발생하였다. 무경운에 100% 지표피복 처리된 옥수수 시험포의 연유사량은 $0.1{\sim}2.2\;ton/ha/year$, 등고선에 평행으로 경운한 시험포는 $10{\sim}27\;ton/ha/year$, 그리고 등고선에 직각으로 경운한 시험포는 $11{\sim}33\;ton/ha/year$으로 나타났다. 감자 시험포의 연유사량은 비닐피복 시험포에서 $0.1{\sim}0.2\;ton/ha/year$, 등고선에 평행으로 경운한 시험보에서 $16{\sim}24\;ton/ha/year$, 그리고 등고선에 직각으로 경운한 시험포에서 $16{\sim}31\;ton/ha/year$으로 측정되었다. 파종이나 수확 후에 큰 비가 내리면 많은 양의 유사가 발생하였다. 감자는 수확 시 고랑과 이랑을 만들고 고랑에는 격벽을 설치하고 옥수수는 지면에서 일정한 높이 이상만 수확하여 유사의 양을 줄일 수 있는 방법이 제안되었다. 또한 동절기 풍식과 눈 녹은 물에 의한 수식을 최소화하기 위하여 동상방지대책의 개발이 필요한 것으로 나타났다. 고랭지 경사농경지의 최적관리방법으로 무경운 영농, 지표피복, 고랑격벽의 설치를 통한 이랑붕괴의 최소화, 승수로의 설치, 완충지의 설치, 동상방지방법의 개발, 겨울작물의 재배 등이 제안되었다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회B
• /
• pp.2904-2909
• /
• 2008

The liquid phase LPG injection (LPLi) system (the 3rd generation technology) has been considered as one of the more promising fuel supply systems for LPG vehicles. To investigate the characteristics of LPG residue in LPLi system, various rubbers were reacted with LPG fuels. The results showed that the residue of a cover rubber in a fuel pump after test increased 10 times higher than that before test. Furthermore, the amount of sulfur, nitrogen species which are considered as main sources in deposit formation in the LPLi fuel injector were also found to be higher than that in original LPG fuel. And these residues made the core parts of LPLi injector such as a neddle and a nozzle, partially worn, which eventually causes a leakage in LPLi injectors.

• 대한기계학회논문집B
• /
• 제33권4호
• /
• pp.272-277
• /
• 2009

The liquid phase LPG injection (LPLi) system (the 3rd generation technology) has been considered as one of the most promising fuel supply systems for LPG vehicles. To investigate the reaction characteristics of LPG with rubber parts in LPLi system, various rubbers were tested. The results showed that the amount of residue from the cover rubber of a fuel pump was increased about 10 times after testing. Furthermore, the amount of sulfur and nitrogen species which are considered as main sources of deposit formation in LPLi fuel injectors were also found to be higher than those in original LPG fuel. In addition, these residues made the core parts of LPLi injector such as needle and nozzle, partially worn, which eventually causes leakage in LPLi injectors.

• 한국잡초학회지
• /
• 제31권2호
• /
• pp.167-174
• /
• 2011

본 연구는 콩 재배시 동계 피복작물인 크림손클로버, 헤어리벳치, 호밀의 예취물 피복이 잡초발생과 콩생육 및 수량에 미치는 영향을 알아보고자 실시되었다. 연구 결과 크림손클로버, 호밀, 헤어리벳치 피복구에서 모두 이른 봄 잡초 억제율이 높았으며, 콩 정식 64일 후에도 헤어리벳치 피복구는 87.6%, 호밀 피복구는 72.0%로 콩의 초관이 형성될 때까지 높은 잡초억제율이 유지되었다. 그러나 크림손클로버 피복구는 시간에 흐름에 따라 잡초억제율 감소폭이 커서 여름잡초가 많이 발생한 콩 정식 64일 후에는 4.1%로 현저하게 감소되었다. 헤어리벳치 피복구는 월년생과 다년생잡초에 대한 억제율이 98.2%로 가장 높았고, 호밀 피복구는 광엽잡초 억제율이 57.6%인 반면, 화본과잡초 억제율은 93.8%로 광엽잡초 보다 화본과 잡초에 대한 억제 효과가 높았다. 크림손클로버 피복구에서는 다년생과 월년생잡초 억제효과가 거의 없었으며, 광엽잡초에 대한 억제효과도 없었다. 콩의 후기 영양생장기에 초장을 조사한 결과 무피복에 비해 크림손클로버, 헤어리벳치, 비닐 피복구에서 각각 6.9%, 20.2%, 22.0% 초장이 더 길었으나, 호밀 피복구는 오히려 초장이 짧았다. 콩의 입비대시에는 호밀 피복구의 콩 생육이 다소 회복이 되었으며, 수확기때 콩 수량은 헤어리벳치 피복구 ${\fallingdotseq}$ 비닐 피복구 > 크림손클로버 피복구 ${\fallingdotseq}$ 호밀 피복구 > 무피복구 순이었다.

• 한국토양비료학회지
• /
• 제49권5호
• /
• pp.531-540
• /
• 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
• /
• 제14권3호
• /
• pp.402-413
• /
• 2001

Food safety is a term broadly applied to food quality that may adversely affect human health. These include zoonotic diseases and acute and chronic effects of ingesting natural and human-made xenobiotics. There are two major areas of concern over the presence of residues of antibiotics in animal-derived foodstuffs with regard to human health. The first is allergic reactions. Some antibiotics, such as penicillins can evoke allergic reactions even though small amounts of them are ingested or exposed by parenteral routes. The second is development of antibiotic resistance in gut bacteria of human. Recently multi-resistant pneumococcal, glycopeptide-resistant enterococci and gram negative bacteria with extended-spectrum $\beta$-lactamases have spread all over the world, and are now a serious therapeutic problem in human. Although it is evident that drugs are required in the efficient production of meat, milk and eggs, their indiscriminate use should never be substituted for hygienic management of farm. Drug should be used only when they are required. In addition to veterinary drugs, environmental contaminants that were contaminated in feed, water and air can make residues in animal products. Mycotoxins, heavy metals, pesticides, herbicides and other chemicals derived from industries can be harmful both to animal and human health. Most of organic contaminants, such as dioxin, PCBs and DDT, and metals are persistent in environment and biological organisms and can be accumulated in fat and hard tissues. Some of them are suspected to have endocrine disrupting, carcinogenic, teratogenic, immunodepressive and nervous effects. The governmental agencies concerned make efforts to prevent residue problems; approval of drugs including withdrawal times of each preparation of drugs, establishment of tolerances, guidelines regarding drug use and sanitation enforcement of livestock products. National residue program is conducted to audit the status of the chemical residues in foods. Recently HACCP has been introduced to promote food safety from farm to table by reducing hazardous biological, chemical and physical factors. Animal Production Food Safety Program, Quality Assurance Programs, Food Animal Residue Avoidance Databank are para- or non-governmental activities ensuring food safety. This topic will cover classification and usage or sources of chemical residues, their adverse effects, and chemical residue status of some countries. Issues are expanded to residue detection methodologies, toxicological and pharmacokinetic backgrounds of MRL and withdrawal time establishments, and the importance of non-governmental activities with regard to reducing chemical residues in food.

• 한국환경농학회지
• /
• 제28권1호
• /
• pp.53-58
• /
• 2009

The propose of this study was to find out optimum conditions for no-tillage rice-winter cover crops cropping system. A field research was conducted to evaluate productivity and quality of rice cultivars (Dongjinbyeo and Junambybyeo) in rice-winter cover cropping systems at Doo-ryangmyeon., Sacheon, Gyeongsangnam-do, Korea from January 2005 to October 2006. The experimental soil was Juggog series (fine silty, mesic family of Fluvaquentic Eutrndepts). The rice cultivars were experimented under some different high residue farming systems, i.e. no-tillage no treatment (NTNT), no-tillage amended with rice straw (NTRS), no-tillage amended with rye (NTR), no-tillage amended with Chinese milkvetch (NTCMV), tillage no treatment (TNT), and conventional cropping system (Control). The miss-planted rate was 8.8% in 2005 and range of 10.8% to 13.3% in 2006 at NTR, and the other treatments were carried out at miss-planted rate ranging from 1.2% to 5.0%. Tiller numbers of Junambyeo, and Dongjinbyeo in both of years were the highest in Control, and decreased nearly in NTCMV, NTR, NTRS, NTNT, and TNT in that order. The lowest grain yield was observed in TNT both cultivars due to the lower tiller numbers per area, and spikelet numbers per panicle. Also, no-tillage treatments were lower grain yield than control. On the other hand, 1,000-grain weight was lowest in control due to higher tiller numbers per area, and spikelet numbers per panicle. Ripened grain ratio was a similar aspect in all treatments. The palatability score of milled rice was lowest in control while protein content of milled rice was highest in control. The NTCMV was considered an effective sustainable farming practice for rice yield and quality.