Winter hairy vetch (HV) can be used as green manure with conventional tillage system (CT), in which chemical N fertilizer required for cultivation of sub-sequent com could be fully saved, or as cover crop with no-tillage system (NT) in which soil could be protected from erosion, control of weed, and the reduction of N fertilizer application. This experiment was carried out to compare the enrichment of soil mineral nitrogen (SMN) at corn root zone, and the changes of com growth and N uptake according to HV amounts (winter fallow, above-ground HV removed, intact HV, and HV added from aboveground HV removed) under two tillage systems in the upland field of National Crop Experiment Station, Suwon, Korea in 1996. HV cultivation during winter decreased SMN a little at com planting. HV incorporation with CT increased SMN rapidly during early growth stage according to rapid decomposition of Hv. SMN by HV cover with NT was increased slowly and its increase was higher in the surface soil (soil layer 0-7.5cm) compared to deep soil layer 7.5-22cm. Com growth and N status at corn silking stage, com yield and N uptake at harvest were increased in proportion to aboveground HV amounts regardless of tillage system. Average hairy vetch nitrogen (HV-N) uptake efficiency by com was 10% higher with CT than with NT in which average HV-N uptake efficiency was 43 %. Corn yields were not different between two tillage systems, but corn N uptake was increased by 33 kgN/ha more with CT than with NT due to the increase of corn N concentration. The increase of SMN and com N uptake from HV cover with NT could not be disregarded though those with CT were higher than with NT

A field experiment was conducted to investigate the performance of three legume species in a zero-tillage, non-fertilized rice field in a temperate zone. Before the experiment for 5 years, from 1995 to 1999, plant growth patterns of three legume species grown as over-wintering (October-May) cover crops on a paddy field were maintained to study N balance and ~textrmN2 fixation. Decrease in plant density accelerated from after winter to flowering from 1,090, 320, and 5 to 732, 232, and 6 plants ~textrmm-2 in Chinese milk vetch (CMV), white clover (WC), and hairy vetch (HV), respectively. Total dry weights of plants above-ground level were 0.05, 0.11, and 2.43 g ~textrmplant-1 . in WC, CMV and HV respectively but steeply increased at ripening up to 0.77, 2.33, and 26 g ~textrmplant-1 . The root dry weight of HV and CMV rapidly increased while in WC, root dry weight increased slightly towards flowering. The highest nodule numbers were recorded in CMV to April thereafter WC produced the highest. Nodule size was distributed within 7mm in CMV but it was larger in HV varying from 1 to 10mm. Shoot N (g ~textrmm-2 ) greatly increased from over-wintering to flowering in CMV, HV and WC and it ranged from 1.66, 0.5 and 1.92 to 12.6, 3.1 and 13.02 g ~textrmm-2 , respectively. After wintering, the initial shoot N content (%) was more in CMV. Root N content (%) was constant or slightly decreased in HV and WC. Soil total N in the control plot (clean fallow) was the highest on Mar. 2 then decreased rapidly to flowering. Soil N content was constant in HV plots whereas it was low in WC plots for the entire growth period except just after winter. Maximum nitrogenase activities were 9, 37.8, and 131 mol ~textrmC2~textrmH4 ~textrmplant-1 ~textrmhour-1 . in CMV, HV, and WC, respectively. Nitrogenase activity showed a direct correlation with nodule number, size and fresh weight. As a cover crop preceding a rice crop, CMV is more suited to colder regions due to its earlier ripening characteristics. Hairy vetch and WC are recommended for regions with a mild winter and a long summer owing to their late ripening and great N fixation activity.

이 시험은 논을 무경운으로 15년간 관리한 상태에서 토양의 변화, 벼 수량구성요소와 수량 및 미질을 경운답에서의 그 것과 비교한 결과를 요약하면 다음과 같다. 1. 토층의 형성정도를 보면 11년간 무경운상태로 관리한 논은 토양 상층에 5cm정도의 유기물층이 형성되었으며, 이 층에 유기물을 비롯한 양이온과 인산이 집적되었다. 2. 무경운답의 작토층은 경운답의 작토층에 비하여 유기물함량은 높으나, pH와 양이온, 인산의 함량이 낮았으며, 가비중과 고상의 비율이 높은 반면 액상과 기상의 비율은 낮았다. 3. 경운답은 표토는 매우 부드러우나 토심 5cm정도부터 급격히 단단해 지는 것에 비해 무경운 1년답에서는 표토가 매우 단단하였으나, 무경운으로 관리하는 기간이 길어짐에 따라 표토는 물론이고 경반층 이하에서도 부드러워졌다. 4. 수량구성요소와 수량을 보면 입수, 등숙률, 천립중 다같이 경운방법간에 비슷하였으며, 수량은 유의적인 차이가 인정되지 않았다. 또한 무경운 연속재배에 따른 수량의 변화패턴은 일정한 경향을 볼 수 없었다. 5.쌀의 도정 및 품위특성을 보면 무경운답과 경운답에서 생산된 쌀간에 차이가 없었다.

No-tillage (NT) practice for corn production has advantages of reduction of soil erosion and energy conservation. Research on effects of NT for sweet corn or super sweet corn is very limited. Hybrids of sugary (su) and shrunken-2 (sh2) were tested under NT and conventional tillage (CT) practices to investigate plant characters, ear characters, fresh yield, and grain yield. Sugary hybrids were Golden Cross Bantam 70 (GCB70), Sprint, Geumdanok, and Danok3. Shrunken-2 hybrids were BSS9472, Cambella90, GSS9299, Jubilee, KS-Y-65, and Chodangok1. Emergence rates under NT were lower than those under CT for su, while there was no difference between tillage systems for sh2. There were no differences between CT and NT for days to tasseling and silking, plant height, and ear height for both su and sh2. Ear characters such as ear length, number of kernel rows, number of kernels per row, and t100-kernel weight under NT were not significantly different from those under CT. There were no differences between two tillage practice for fresh and grain yield, rather they showed trend of increases under NT practices. Results from this trial indicate that NT practice for both su and sh2 cultivation may be possible to recommend to farmers.

Selective catalytic reduction and selective non-catalytic reduction processes are mainly used to treat nitrogen oxidants generated from fossil-fuel combustion. Especially, the selective non-catalytic reduction process can be operated more economical and designed more simply than the selective catalytic reduction. For this reason, many researchers carried out to increase the removal efficiency of nitrogen oxidants in the condition of low oxygen concentration by using the selective non-catalytic reduction process. However, this study was flue gas contained high oxygen concentration of 20(v/v%) with ammonia as a reducing agent. Moreover, it carried out experiment with many factors that are reaction temperature, retention time, initial NO concentration, NSR(normalized stoichiometric ratio). It was determined optimal operating conditions to improve NO removal efficiency with SNCR process. The De-NOx efficiency was increasesd with NSR, initial NO concentration and retention time increasement. This study has NO removal efficiency over 80% in the high oxygen concentration as well as low oxygen concentration. The injection of reducing agent may be considered for SNCR process and facility operation in 850℃ of optimal condition.

호남평야지에서 건답직파재배와 무경운기계이앙 재배시 적정 연속재배 년수 및 윤환재배법을 구명하고자 '95년부터 '00년까지 호남농업시험장 수도포장인 전북통(미사질양토)에서 동진벼를 공시하여 시험한 결과를 요약하면 다음과 같다. 1. 무경운 기계이앙재배시 표층의 공극율이 건답직파에 비해 높았고 가비중은 무경운 재배시 가벼웠으며 무경운 재배를 계속할수록 표토는 볏짚의 환원에 따른 유기물 함량이 높아지고 물리성이 개선되나 심토는 경운 생략에 따른 물리성 악화와 유기물 함량의 감소로 벼 뿌리가 표층에 많이 분포하는 경향이었다. 2. m2 당 경수는 건답직파보다 무경운이앙에서 많았고 5년연속 건답직파시 275개로 경수의 감소가 현저하였으며 유효경비율은 재배양식간 큰 차이없이 60%내외였다. 3. 무경운재배를 계속 할 경우 잡초의 발생량이 크게 증가하였는데 1년생 잡초인 사마귀풀, 둑새풀이 많이 발생하였고, 다년생 잡초인 나도겨풀의 발생량이 많았으며 잡초성벼는 경운이앙재배에 비해 많이 발생하였지만 무경운 연속 재배년수에 관계없이 2-3%였다. 4. 건답직파를 3년 연속 했을 경우 잡초성벼 발생율은 3.7%가 되었으며 이듬해 담수직파로 윤환재배를 한 결과 2%로 감소하였지만 다시 건답직파재배를 했을 때 7.2%가 발생하여 윤환재배의 효과가 적었다. 5. 도복은 담수직파에서는 3으로 재배양식중 가장 심하였고 다음으로 무경운 기계이앙 순이었으며 건답직파와 경운이앙재배에서는 경미하였는데 도복 정도는 재배년차간 차이보다는 재배양식에 따라 발생정도가 다르게 나타났다. 6. 출수기는 무경운 이앙에서는 경운이앙과 비슷하였으나 건답직파와 담수직파에서는 년차간 변이가 심하였으며 쌀수량은 담수직파의 경우 년차간 큰 차이없이 경운이앙에 비해 약간 낮았고 무경운이앙에서는 5년연속 재배시 다소 감소되었으며 건답직파에서는 5년연속 재배시 62%로 크게 감소되었다.다.0일이었다.환경적응성이 낮은 경향이었다.은 모두 경운 유 ㆍ무에 관계없이 시비수준이 높을수록 높은 경향을 보였고, 10일에 최고수준을 보인 후 완만한 감소를 나타냈으며, K+, Ca2+에 비해 Mg2+이 보다 낮은 함량을 보였다.989년산 일반계를 10분도와 12분도로 도정하였을 때 도정도에 따른 밥맛의 차이는 없었다.X>CoOx는 Co3O4 로 존재하고, 반응 전의 경우에는 이와는 다른 chemical state를 보여주었다. XRD 및 XPS 결과를 바탕으로, 촉매표면에 존재하는 Co3O4 의 외부표면이 Co2TiO4 와 CoTiO3 같은 CoTiOx 로 encapsulation되어 있는 모델구조를 제안할 수 있고, 이는 반응시간의 함수로 나타나는 촉매활성에 있어서 전이영역의 존재를 잘 설명할 수 있을 뿐만 아니라, XRD와 XPS에서 얻어진 촉매의 물리화학적인 특성을 잘 반영할 수 있다. 나타냈고, 골격근과 눈 조직에서 피루브산에 대한 LDH의 친화력이 상당히 크므로 LDH가 혐기적 조건에서 효율적으로 기능을 하는 것으로 사료된다.5) and "Cleanliness of clothes ＆ features" (p ＜0.05) of VIP ward were significantly higher than those of a general ward.tive to apply.아울러 고려(考慮)해야 한다. 이것은 고무기술자(技術者)가 당면(當面)해야할 과제(課題)에 속(屬)하며 바람직 한것은 본장(本章)의 내용(內容)이 여러 상황하(狀況下)에서 당면(當面)한 문제(問題)에 대(對)해 어떻게 대처(對處)해 야 할지를 모르는 여러 기술자(技術者)

For the purpose of predicting air pollutants concentration in Pusan coastal urban, we used an Eulerian model of flow and dispersion/chemistry/deposition process considering SST effects which estimate through POM. The results of air quality model including emission from various sources show that the seasonal variation pattern of respective pollutants was affected by the seasonal SST fields and local circulation. Horizontal deviation of diurnal SST was 2.5∼4K, especially large gradients in coastal region. Through numerical simulation of wind fields we predicted that local circulation prevailed during daytime in summer and nighttime in winter. So high concentration distribution showed toward inland in spring and summer seasons, while high concentration distribution showed at inland near coast in autumn and winter.

Nitrogen applied as fertilizer for crop production is partly absorbed by plant, and the remaining nitrogen in soil might be leached out through complicated processes to the subsoil layer. Especially, NO₃　N in leachate causes environmental pollution. The purpose of this study was focused on understanding of uptake of nutrients by plants, the behaviors of nutrients in soil and the possibility of leaching loss when nitrogen fertilizer and completely decomposed compost were applied. Lysimeters(Volume 0.15㎥, Diameter 62㎝, Height 62.8㎝) were installed for collecting leachate in the Jeju volcanic ash soils. Lysimeter study consisted of thirteen treatments：fallow, fallow with weeding, cropping without fertilizer and compost, three N fertilizer soil surface applications(16, 32, 64㎏/10a), three N fertilizer and compost soil surface applications(16+800, 32+1600, 64+3200㎏/10a), two water dissolved N fertilizer applications(16, 32㎏/10a), and low and high plant densities. N fertilizer was applied as urea. The growth of corn(preceding crop) and potatoes(succeeding crop) and leaching loss were determined during the experimental period. The results obtained were summarized as follows； With increased N, pH of leachate tended to decrease and NO₃　N concentration of leachate increased. NO₃　N leaching loss was remarkably greater in soil from the bare plot without fertilization and the weed control than from plots with medium N rate and was least in the cropping plot without fertilization. NO₃　N concentration in leachates from the water dissolved N fertilizer application plots was 64% of that from the soil surface application plots. The concentration of Ca and K ions and the leaching loss of these ions were least from the cropping plot without fertilization and were greatest from bare plots(T1 and T2) without fertilization. The proportion of leaching and residual N in soil increased as N rate increased indicting that higher N rates increase the possibility of N leaching to subsoil layer. The proportion of N leaching losses was lower at the low N rate and the high plant density. In future, fertilization prescription which can maximize fertilizer use efficiency and minimize the pollution of ground water will be needed for conserving the environments.

해상교통법에서는 다른 선박을 피하여야 하는 의무를 가지는 서로 다른 두가지 그룹의 선박이 있다. 하나는 다른 선박의 진로를 피하여야 할 선박이고, 다른 하나는 통항을 방해하지 아니할 선박이다. 통항불방해의 무선박의 개념은 1972년 국제해상충돌방지규칙의 1987년 개정에서 제8조 (f)항을 채택함으로써 분명하여졌다. 그러나, 한국정부는 이러한 규정을 한국의 국내법에 현재까지 수용하지 아니하였다. 그리하여 통항불방해의무선박의 정의와 적용에 대하여는 학계에서조차도 크게 논의되지 않고 있다. 최근 대법원은 통항불방해의무선박이 관련된 충돌사건에 대한 판결을 내렸다. 필자는 외국 학자들의 논문과 국제해사기구의 문서를 참조하면서, 통항불방해의무선박에 대한 자신의 견해를 밝히면서 대법원의 판결을 비판하고 있다.

무경운 담수표면산파재배시 잡초성벼의 발생양상과 비선택성 및 토양처리제를 이용한 잡초성벼 방제 결과는 아래와 같다. 1. 무경운에 의해 토양표면에서 월동한 잡초성벼의 생존율은 92.7%였고 재배벼는 4.3%였다. 2.토양내의 잡초성벼 발생심도는 건답에서 6.8cm, 무논에서 3.0cm, 그리고 무경운답에서 1.5cm로, 무경운답의 잡초성벼 발생은 건답과 무논에 비하여 토양 표층부위에서 주로 발생하였다. 3. 4월 하순의 우리나라 중부지역 평균기온인 13℃ 에서 잡초성벼 발아에 소요되는 일수는 14-15일이었다. 4. 무경운상태에서 포장 표면위에 떨어져 있는 잡초성벼의 발아를 유도한 후 비선택성 제초제인 paraquat 처리한 결과 92.2%의 잡초성벼를 방제할 수 있었으며, 토양처리제 중 가장 높은 출아억제를 보인 제초제는 oxadiazon으로 53.3%의 방제 효과가 있었다. 5. Paraquat과 oxadiazon의 체계처리에 의해 96.4%의 잡초성벼를 방제할 수 있었다.

A field experiment was carried out to observe the weed control effects of vetch and to evaluate vetch characteristics on clay loam soil in no-till direct-sown rice-vetch cropping systems. The effects of weed control, forage productivity, and N content of vetch plants were investigated. With the progress of plant growth, density of Chinese milk vetch (Astragalus sinicus L.) gradually decreased, but densities of foxtail and other weeds decreased steeply due to the depression by the over-shaded vetch canopy in a no-till direct-sown rice-vetch cropping paddy field. The vetch density in tillage systems was lower than in notillage cropping systems. Lower vetch density occurred with an increase in foxtail density and other weeds. Weed control effect increased by the progress of vetch growth, which indicated that the vetch canopy over-shaded the weeds. Vetch straw was degraded rapidly submergence after with water at the time of wet sowing of rice. Early harvesting of vetch seed resulted in lower seed germination. To acquire enough seedlings without re-sowing, the harvesting of seed should be delayed at least 28 days after the flowering stage in order to ensure the vetch population is sustainable in a no-till direct-sown rice-vetch cropping system. In order to improve the survival of vetch plants, vetch seeds should germinate from the heading .stage to before the full-ripening stage of rice plants. To enhance the percent of over-wintering survival, vetch seeds should germinate no later than the end of October in southern Korea. The dry weight of vetch plants increased with the progress of vetch growth until the flowering stage but N content decreased for 30 days from before the flowering stage (2.9%) until the ripening stage (1.8%). We concluded that Chinese milk vetch could have an effect on weed control before the flowering stage, sustainability without re-sowing of seed annually, and effective green manure for rice pre-crop in no-till direct-sown rice-vetch relay cropping systems.

In rice-barley cropping systems, efficient utilization of barley straw is essential, both to improve the soil fertility and to conserve the environment. In order to identify the effects of barley straw mulch rates in rice cultivation, a rice cultivar, 'Gancheogbyeo', was directly seeded on a no-tillage field synchronized with barley harvesting with five barley straw mulch rates, i.e., 0, 2.5, 5.0, 7.5 and 10.0 ton h a-1 and agronomic characters of rice and soil nitrogen were determined. The increasing of barley straw mulch rates. Dominant weed species, chestnut, occurred in large amounts in no mulching or lower mulch rates than in higher mulch rates. The content of N H4 ＋ -N in soil applied with high barley straw mulch rates was lower during the month after seeding, and then it was higher at heading date, compared with lower mulch rates or no mulch plot. As the barley straw rate increased, maximum tillering stage was delayed, and plant height was reduced. Although the lodging of rice plants was seldom observed in all plots, the breaking strength of the culm was significantly higher in the mulch rate of 10.0 ton h a-1 . With an increase of barley straw mulch rate, the effective tillering rate and spikelet number m-2 decreased while ripened grain ratio increased. The rice grain yield was slightly decreased with an increase of barley straw mulch rate, although significant differences were not found all barley straw mulch rates. These results suggest that there is no significant yield loss although the total barley straw production, approximately 5.0 ton h a-l in the present study, apply in the paddy for the following rice cultivation by no-tillage direct seeding.ect seeding.

The concentration of air pollution in a large city such as Pusan has been increased every years due to the increase on fuel consumption at factories and by vehicles as well as the gravitation of the population. In this study, we have analyzed NO2 concentration data and various data of meteorological factors during 1994-1997 to investigate the characteristics of NO2 concentration and how the high NO2 concentration is generated under the meteorological condition. According to the study, NO2 peak concentration at most sites occurred about 1h later after the rush hour. In the characteristics of emissions in sites, sinpyeong- dong was highly contributed to point source while the other sites were highly contributed to line source. The high NO2 concentration had high generation probability when temperature contained typical seasonal characteristics and wind speed was low. Using the relationship between meteorological factors and the daily average NO2 concentration, correlation analysis was practiced. The seasonal variation of the daily average NO2 concentration was correlated with air temperature, solar radiation and wind speed, but the correlation coefficient between meteorological factors and the daily average NO2 concentration was not so much high. Thus we have known that the daily average NO2 concentration is partially explained by meteorological factors.

No-till direct seeding cultivation of rice has major advantages such as saving of labor and cost by eliminating tillage, preparation of seed bed and trans-planting procedure compared to the conventional transplanting cultivation. A field experiment was conducted to evaluate the effects of straw treatment and nitrogen levels on the rice growth in no-till direct-seeding cultivation. Rice straw, vetch straw, and the mixture of both of the straws were mulched on the surface of soil before seeding while 4 levels of nitrogen fertilizer, 0, 7, 9, and 11 kkg/10a respectively, were applied at 3 split times, 3-weeks after sowing, 5-weeks after sowing and the panicle initiation stage. Mulching of vetch straw significantly reduced seedling establishment of rice which may be attributed to low oxidation-reduction potential of soil by vetch mulching treatment. Vetch straw increased the concentration of soil ammonium leading to an extension of the greenish leaf to panicle initiation stage. Agronomic nitrogen use efficiency (AD EN ) in heavy-mixed straw mulching plots was lower than other treatments. Grain yield and AU EN in the vetch treatment were less affected by fertilized N levels. Conclusively, it is suggested that heavy straw mulching was not efficient for rice seedling establishment and nitrogen usage.e.