• 한국농공학회지
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• 제44권7호
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• pp.53-63
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• 2002

Runoff, sediments and nutrient losses were studied under different patterns of paddy field management: (1) fall and spring plowing (Plowing)i (2) fall plowing for half of plot and spring plowing (Semi-plowing); (3) no-till for fall and spring plowing (Un-plowing) during the non-cropping period in the southern Korea for two years. The runoff amount and initial abstract were significantly affected by plowing practices. Un-plowing plot showed the highest runoff amount among treatments. The concentrations of sediment from Plowing plot were much higher than those from Un-plowing plot, especially after (all plowing. Sediment losses from Plowing plot were 25% more than those from Un-plowing plot. There was significant difference in nutrient losses via runoff water and sediment according to plowing practice. Two-year average of losses of N from paddy field during non-cropping period were 9.42 kg ha$\^$-1/, 8.17kg ha$\^$-1/, and 7.76 kg ha$\^$-l/ for Un-plowing, Semi-plowing, and Plowing plot, respectively, while losses of P were 0.64 kg ha$\^$-1/, 0.58 kg ha$\^$-1/, and 0.58 kg ha$\^$-1/ for each tillage system. Losses of total-N, ammonia-N, nitrate-N, Total-P from Un-plowing plot was larger than those from Plowing and Semi-plowing plots during study period.

• Journal of Biosystems Engineering
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• 제29권3호
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• pp.207-216
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• 2004

This study was intended to investigate the characteristics of ride vibrations transmitted to tractor operator during rotary tillage and plowing operations. Seat accelerations of a 41 ps diesel tractor in rotary tillage and plowing were measured and evaluated as specified in the ISO 2631-1. Effects of working speed and tilling depth on ride vibration were investigated. The level of ride vibration was also evaluated in terms of health guidance caution zones. Some of the results of the study are as follows: 1. The level of ride vibration in plowing was about 4.3 times greater than in rotary tillage. 2. The effect of working speed in rotary tillage differs depending upon the tillage depth. The level of ride vibration was increased with the speed, but it decreased over a certain tillage depth. Fore and aft vibration was 2.2-2.7 times severer than horizontal and vertical vibrations. Dominant frequency band was 1-3.15 ㎐ in fore and aft, 1-3.15㎐ and 16-25㎐ in horizontal, and 16-25㎐ in vertical directions. 3. Plowing reduced the ride vibration by 42.8-50.2%. But its positive effect decreased as the plowing speed increased. In plowing operation, ride vibration was similar degrees in fore and aft, horizontal and vertical directions. The dominant frequency band in plowing operation was 1-2.5㎐ in fore and aft, 1-2.5㎐ in horizontal, and 1-8㎐ in vertical directions. 4. On a basis of daily work hours of 4, total level of ride vibrations in plowing operation is likely to be harmful to operator's health.

• 한국연초학회지
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• 제1권2호
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• pp.111-119
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• 1979

심경과 多肥栽培가 버어리種 담배의 收量 및 品質에 미치는 영향을 구명하고자 耕土깊이를 10,20,30cm로 하고 施肥水準을 標準施肥(138kg/10a), 20%增肥, 40%增肥로 하여 3년간(1976-1978) 實驗한 결과 收量 및 品質 공히 심경 다비할수록 증가하여 수량은 耕土깊이 30cm 구에서 5%, 40%增肥區에서 13%가 증가하였으며 품질은 심경과 다비로 각각 2%씩 증가하였다.

• 물과 미래
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• 제10권2호
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• pp.81-90
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• 1977

The research is conducted to study the effect of the soil physical properties in the direct sowing culture on the water requirement, growth, and yield of rice with Early-Tongil at the experimental paddy field of the Sangju agri. and seri. junior college in Keyngbuk province from 6th May to 15th September in 1977. The experimental plots are designed with the four plots which are non-irrigated standard (plowing to 15cm), non-irrigated deep lowed (plowing to 25cm), irrigated standard (plowing to 15cm), and irrigated deep plowing plot (plowing to 25cm) and also each plot is repreated four times by the split plot design. The results obtained are summarized as follows: 1) The soil sample was ML to 10cm depth from ground surface and those from 10cm to 20cm depth and from 20cm to 30cm were CL. Each specific gravity was 2. 6, 2. 6 and 2. 7. 2) The weather during culturing period was the sane as the normal year of mean temperature. The precipitation was little and the distribution of it was disordered comparing to normal year but the heavy sunshine gave good effect on ripening. 3) Percolation loss was increased more at the non-irrigated plot than at the irrigated plot, and that of deep-plowed plot was increased more. 4) Grain yield per 10a. of non-irrigated deep plowed plot was 898kg, it was greated than others but there wa no significance. 5) A significant difference in the number of spikelets per panicle was found between nonirrigated plot and irrigated plot, and the number of spiklelets per panicle at the nonirrigated plot was more than that of the irrigated plot. But there was no significance in the other yield components-number of panicle, fertility abd ripening ratio-at the irrigated plot, ut weight of 100 grains was higher at non-irrigated plot. 6) Yield and growth at the deep plowed plot were higher than those of standard plowed plot.

• 한국지반공학회논문집
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• 제16권3호
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• pp.89-89
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• 2000

The shear behavior of any interface is a function of the fundamental properties of both materials at the interface. This study aimed at investigating the effect of planar surface roughness on the stress-horizontal displacement curve at theinterfaces composed of various geomembrane textures and granular materials. In addition, the extent of surfacialscarring on smooth geomembranes against granular materials during shearing induced by plowing effect was studied. It wasobserved that the displacements required to achieve peak and residual interface resistance, and the stress-displacementcurve at the interface vary greatly with the surface roughness of geomembrane. Quantification of surface roughnessvariations on smooth geomembrane due to plowing effect showed that the surfacial scarring during shearing by the soilparticles is directly related to both the normal stress and the angularity of the soil particles at the interface. The findingsof this study can be used to provide the useful information for the design and selection of counterface materials.

• 한국토양비료학회지
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• 제35권6호
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• pp.352-360
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• 2002

자운영재배 논의 경운시기에 따른 질소시비량 절감 및 토양개선효과를 구명하기 위하여 자운영을 개화성기, 개화종기 및 결실기에 경운하고 기계이앙재배시 질소수준이 벼의 생육, 수량 및 토양의 이화학적특성에 미치는 영향을 검토한 결과를 요약하면 다음과 같다. 자운영 경운시기의 생초중은 각각 ha 당 22,500, 20,000, 12,500 kg이였고 건물중에 있어서 전질소함량은 2.95, 2.66, 2.47%이였으며 탄질율은 15.7, 18.0, 19.2이였다. 자운영 재배 및 시용후 토양중 전질소, 유기물함량은 높아지고 유효인산함량은 낮아져 화학성이 개량되었으며 용적밀도, 고상율은 낮아지고 공극율이 증대되어 물리성이 개선되었다. 경운 시기별 토양 중 $NH_4-N$ 함량은 개화성기 > 개화종기 > 결실기 순으로 분얼기에 가장 높았고 질소수준이 높을수록 많았으며 관행에 비하여 생육후기까지 높게 발현되었다. 자운영 후작벼 재배시 성숙기 수수 확보가 많아 유효경비율이 높고 수도체중 전질소함량은 질소수준이 높을수록 많아져 관행에 비하여 엽색수치가 높았다. 질소흡수량은 개화성기 > 개화종기 > 결실기 순으로, 질소수준이 높을수록 많았고 질소이용률은 $33kg\;ha^{-1}$ (70% 절감)시 높았다. 자운영을 개화성기 및 개화종기에 경운시 $m^2$당영화수 확보가 많았으며 개화종기 및 결실기 경운시 등숙비율이 높아졌다. 쌀 수량은 개화성기 및 개화종기 경운시 5,770, $5,580kg\;ha^{-1}$로 질소수준 $55kg\;ha^{-1}$(50%절감)에서 관행에 비하여 각각 9%, 8% 증수되었고 결실기 경운시 $5,120kg\;ha^{-1}$로 질소수준 $77kg\;ha^{-1}$(30% 절감)에서 1% 증수되었다.

• 한국정밀공학회지
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• 제12권12호
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• pp.72-80
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• 1995

Ultraprecision machining technology has been playing a rapidly increasing and important role in manufacturing. However, the physics of the micromachining process at very small depth of cut, which is typically 1 .mu. m or less is not well understool. Shear along the shear plane and friction at the rake face dominate in conventional machining range. But sliding along the flank face of the tool due to the elastic recovery of the workpiece material and the effects of plowing due to the large effective negative rake angle resultant from the tool edge radius may become important in micromachining range. This paper suggests an orthogonal cutting model considering the cutting edge radius and then quantifies the effect of plowing due to the large effective negative rake angle.

• 한국정밀공학회지
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• 제13권1호
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• pp.53-61
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• 1996

A clear understanding of the surface formation mechanism due to cutting is very important to help produce a good quality surface. Much of the roughness along the length of a bar being cut in a lathe can be explained in terms of macroscopic tool shape and feed rate. However, the roughness along the direction of cutting requires a different explanation. The formation of surface roughness is a problem in flow and fracture of materials in the vicinity of the tool edge. On a microscopic scale the cutting edge is rounded because it is impossible to grind a perfectly sharp cutting edge. Even if a perfectly sharp cutting edge were obtained it would soon become dull as a result of rapid breakdown and wear of the cutting edge. A research project is proposed in which in the main object is to model the surface formation mechanism due to cutting. The tool was assumed to be dull, that is, its edge has a finite radius. In order to study the effect of the radius of cutting edge on the surface formation, tools having different cutting edges were used. For orthogonal cutting experiment, cast iron and glass were chosen as brittle materials. Plowing forces acting in the cutting edge were estimated and its effect on the surface roughness was studied by observing the machined surface using optical microscope.

• 한국환경농학회지
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• 제21권1호
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• pp.1-6
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• 2002

우리나라의 시설참외 주산지인 성주지역의 시설참외 연작 대책으로 객토와 심경에 의한 토양 화학성분의 변화와 뿌리혹선충 억제효과를 조사한 결과는 다음과 같다. 시설참외 연작 대책으로 많은 양의 객토를 함으로 EC는 4.30 dS/m에서 1.80 dS/m 58%, 유효인산은 406 mg/kg에서 182 mg/kg으로 55% 감축되고 유기물 함량이 16 g/kg에서 11 g/kg으로 31% 줄어 퇴비 등 각종 거름 사용량을 증가해야 하며 뿌리혹선충 밀도 억제효과는 1년 차 89%, 3년 차 84%, 5년 차 69%로 되어 근본 대책이 되지 못하면서 영농비 가중 및 환경 파괴의 문제가 수반되었다. 심토반전 효과도 객토와 비슷하여 EC 4.30 dS/m에서 1.98 dS/m 54% 줄고 유효인산 406 mg/kg에서 329 mg/kg으로 19% 줄었으며 뿌리혹선충 밀도 억제 효과는 처리 후 1년 차 71%, 3년 차 67%, 5년 차 42%가 되므로 처리 3년 이후에는 다른 대책이 필요하였다.

• 한국토양비료학회지
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• 제39권6호
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• pp.334-338
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• 2006

호남평야지 논토양의 대표토양인 전북통에서 벼 담 수직파재배시 토양물리성 개선과 진단시비로 쌀 안정생산을 위한 토양관리기술을 확립하고자 관행, 진단시비, 진단시비+퇴비+규산, 진단시비(LCU 70%)+심경, 진단시비(LCU 70%)+심토파쇄, 무질소구 등 6처리를 하여 2년간(1999~2000) 시험한 결과를 요약하면 다음과 같다. 시험후 심토에서 물리성은 관행에 비하여 경도, 용적밀도, 고상이 낮아지고 공극률이 증가되었으며 그 정도는 심토파쇄>심경 순으로 양호하였다. 시험 후 토양의 화학성은 관행에 비하여 진단시비구, 완효성비료(LCU 70%) 시용 및 토양물리성 개선구에서 유기물함량, 규산함량 등이 증가하였다. 시비질소의 토양중 $NH_4-N$ 농도는 5엽기까지는 심경구에서 가장 높게 발현되었으며 관행 대비 LCU 70% 시용구에서 성숙기까지 발현량이 많았다. 시비질소의 흡수량은 관행에 비하여 진단시비(LCU 70%)+심경, 심토파쇄구에서 많았고 질소이용률도 높았다. 쌀수량은 관행($5.22Mg\;ha^{-1}$)대비 진단시비(LCU 70%)+심토파쇄구에서 8%, 진단시비(LCU 70%)+심경구에서 4% 증수되었으며, 증수요인은 $m^2$당 입수가 많고 등숙률이 높았던 것에 기인한 것으로 사료된다.