• Journal of Biosystems Engineering
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• 제33권1호
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• pp.7-13
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• 2008

The tillage depth control system is one of the most salient control system of tractor implements. A contact-type height sensor was developed to measure ground clearance for the tillage depth control. The height sensor was fabricated in this study, and its efficacy in a tillage depth control system was evaluated. Experiments were conducted in order to determine both static and dynamic detection characteristics of the height sensor using soil bin system on the sampled soil (sandy loam, sand, clay loam). The results of the static detection characteristics showed that in the case, sandy loam soil despite and clay loam soil at a wet basis moisture content of 30%, large measurement errors were observed a due to penetration of a plastic puck into the sampled soil. The results of the dynamic detection characteristics showed that the height sensor detected the distance from the ground of sandy loam soil despite the uneven nature of the ground surface and the changes in traveling speed $1km/h{\sim}5km/h$ at a wet basis moisture content of 10%.

• 한국토양비료학회지
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• 제50권6호
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• pp.634-643
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• 2017

No-tillage is an effective practice to save labor input and reduce methane emission from the paddy. Effects of tillage and cultivation methods on carbon accumulation and soil properties were investigated in the treatments of tillage-transplanting (T-T), tillage-wet hill seeding (T-WS), minimum tillage-dry seeding (MT-S) and no-tillage dry seeding (NT-S) of rice. Soil carbon was higher in NT-S and MT-S, compared to T-T and T-WS. In NT-S and MT-S, soil carbon contents were the highest in the top soil (5 cm depth) and decreased with soil depth. In T-T and T-WS, however soil carbon contents showed no significant difference up to soil depth of 15 cm from the top. Carbon content was the highest in the soil particle size under $106{\mu}m$ and decreased as the soil particle size increased. Contents of water-stable aggregates in NT-S and MT-S were higher than those of T-T and T-WS. In NT-S and MT-S, contents of water-stable aggregates were the highest in the top soil and significantly decreased with soil depth while no significant difference up to the soil depth of 15 cm in T-T and T-WS. Available $SiO_2$ contents in the top soil were the highest in NT-S and MT-S while the lowest in T-T and T-WS. It is concluded that minimum or no disturbance of soil in rice cultivation can increase carbon accumulation in the soil, especially in the top layer, and subsequently contribute to the formation of the water-stable soil aggregates.

• 한국토양비료학회지
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• 제49권5호
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• pp.564-571
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• 2016

As the amount of rice straw collected increases, green manure crops are used to provide the needed organic matter. However, as green manure crops generate methane in the process of decomposition, we tested with different tillage depths in order to reduce the emission. The atmosphere temperature of the chamber was $25{\sim}40^{\circ}C$ during the examination of methane and soil temperature was $2{\sim}10^{\circ}C$ lower than air temperature. The redox potential (Eh) of the soil drastically fell right before irrigated transplanting and showed -300~-400 mV during the cultivating period of rice (7~106 days after transplant). When hairy vetch was incorporated to soil and the field was not irrigated, the generation of methane did not occur from 12 to 4 days before transplanting rice and started after irrigation. Regarding the pattern of methane generation during the cultivation of rice, methane was generated 7 days after transplanting, reached the pinnacle at by 63~74 days after transplanting, rapidly decreased after 86~94 days past transplanting and stopped after 106 days past transplanting. When tested by different soil types, methane emission gradually increased in loam and clay loam during early transplant, whereas it sharply increased in sandy loam. The total amount of methane emitted was highest in sandy loam, followed by loam and clay loam. In all three soil types, methane emission significantly reduced when tillage depth was 20 cm compared to 10 cm. The rice growths and yield were not affected by tillage depth. Therefore, reduction of methane emission could be achieved when application hairy vetch to the soil with tillage depth of 20 cm in paddy soil.

• 한국토양비료학회지
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• 제47권1호
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• pp.8-15
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• 2014

In order to evaluating physiochemical properties of soil under minimum tillage and direct seeding cultivation on dry rice paddy, we conducted to analyze the soil physiochemical characteristics in treatment with 2-year minimum tillage and dry direct seeding (2MT), 3-year minimum tillage and dry direct seeding (3MT), and tillage transplanting cultivation (TT). As results of analyzing soil organic matter (OM) contents with 2 cm soil depth of interval from surface to 30 cm, OM contents with surface soil from 0 to 2MT and 3MT were higher than TT, recorded 34.6, 28.1 and $19.8gkg^{-1}$, respectively. But until 20cm in soil depth, it was not so large on the deviation of OM contents among the 3 treatments comparing with 2cm surface. Beneath 20 cm in soil depths, 2- and 3-year, OM contents in TT were distributed to be lower than 2MT and 3MT. The contents of total nitrogen in 2MT and 3MT were higher than the content in TT across the soil profile. Consequently, though minimum tillage and direct seeding farming is obviously the practice to saving of machinery work and labor, other practices such as continuously input OM should be needed to achieve carbon sequestration goal through minimum tillage and direct seeding on dry paddy.

• 드라이브 ㆍ 컨트롤
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• 제20권4호
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• pp.115-122
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• 2023

This study utilized a discrete element method (DEM) simulation, as one of the virtual field trials, to predict the impact of tillage depth on the rotary blade shaft during rotavator tilling. The virtual field for the simulation was generated according to soil properties observed in an actual field. Following the generation of particles for the virtual field, a sequence of calibration steps followed to align the mechanical properties more closely with those of real soil. Calibration was conducted with a focus on bulk density and shear torque, resulting in calibration errors of just 0.02% for bulk density and 0.52% for shear torque. The prediction of the load on a rotary tiller's blade shaft involved a three-pronged approach, considering shaft torque, draft force, and vertical force. In terms of shaft torque, the values exhibited significant increases of 42.34% and 36.91% for every 5-centimeter increment in tillage depth. Similarly, the vertical force saw substantial growth by 40.41% and 36.08% for every 5-centimeter increment. In contrast, the variation in draft force based on tillage depth was comparatively lower at 18.49% and 0.96%, indicating that the effect of tillage depth on draft force was less pronounced than its impact on shaft torque and vertical force. From a perspective of agricultural machinery research, this study provides valuable insights into the DEM soil modeling process, accounting for changes in soil properties with varying tillage depths. These findings are expected to be instrumental in future agricultural machinery design studies.

• Journal of Biosystems Engineering
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• 제38권2호
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• pp.73-80
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• 2013

Purpose: This study was conducted to compare tillage and loads characteristics of three types of rotavators in farmland working condition of Korea. Methods: Tillage operations using three types of rotavators, i.e. rotary-type, crank-type and plow-type, were carried out in a dry field of Korea. The same prime mover tractor was used for driving three types of rotavators, and under several operational conditions, tillage characteristics such as actual working speed, rotavating depth, rotavating width, actual field capacity, flow of tilled soil, soil inversion ratio, and pulverizing ratio were measured. In addition, loads characteristics like torque and required power of Power Take-Off (PTO) shaft were calculated. Results: The average rotavating depth was smaller than the nominal value for all rotavators, and the difference was the greatest in the plow-type rotavator. Nevertheless, the plow-type rotavator showed the largest rotavating depth. The rotavating width was the same as the nominal value of all rotavators. The flow of tilled soil at the same operational conditions was the greatest in the plow-type rotavator and was the smallest in the rotary-type rotavator. In the most commonly used gear conditions of L2 and L3, the average soil pulverizing ratio was the greatest in the rotary-type rotavator, and followed by crank-type and plow-type rotavators in order. In the gear L2 and L3, the plow-type rotavator also had the lowest average soil inversion ratio while the rotary-type and crank-type rotavators had the same soil inversion ratio each other. The average torque and power of PTO shaft in the gear L2 and L3 were the highest in the plow-type rotavator. The load spectra of PTO shaft applying rain flow counting method and Smith-Waston-Topper equation to the measured torque showed that the modified torque amplitude was the greatest in the crank-type rotavator. This may come from the large torque fluctuation of crank-type rotavator during tillage operations. Conclusions: The three types of rotavators had different tillage and loads characteristics. The plow-type rotavator had the deepest rotavating depth, the smallest soil inversion ratio, the largest soil pulverizing ratio and required PTO power. Also, the crank-type rotavator showed a large torque fluctuation because of their unique operational mechanism. This study will help the farmers choose a suitable type of rotavator for effective tillage operations.

• 한국토양비료학회지
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• 제43권6호
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• pp.798-803
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• 2010

노지 고추재배시 경운 깊이에 따른 유기물 함량을 구명하여 지속적 안전생산에 활용하고자 경운 깊이는 10, 30 및 50 cm로 하고 퇴비의 양을 1, 3 및 5 톤 $10a^{-1}$으로 처리하여 고추를 재배한 결과 다음과 같다. (1) 시험후 토양의 pH는 모든 처리에서 시험전 토양보다 낮아졌으며 EC를 비롯한 Av. $P_2O_5$, K, Ca, Mg, Na는 시험전보다 높았다. 퇴비 시용량 별로는 퇴비 1 톤 $10a^{-1}$ 및 3 톤 $10a^{-1}$ 처리에 비해 퇴비 5 톤 $10a^{-1}$에서 높았다. (2) 고추 생육은 퇴비 1 톤 $10a^{-1}$처리에 비하여 퇴비 3 톤 및 5 톤 $10a^{-1}$에서 좋았으며, 경운깊이 10 cm 및 30 cm에 비해 경운깊이 50 cm에서 좋았다. (3) 고추 수량은 경운깊이 10 cm에서는 퇴비 3 톤 $10a^{-1}$ 처리에서 5,880 kg $ha^{-1}$으로 가장 좋았고, 경운깊이 30 cm 에서는 퇴비 5 톤 $10a^{-1}$ 처리에서 5,610 kg $ha^{-1}$으로 가장 좋았다. (4) 고추식물체의 T-N 함량 및 흡수량은 퇴비 3 톤 $10a^{-1}$ 및 5 톤 $10a^{-1}$ 처리에서 1 톤 $10a^{-1}$처리에 비해 높았다.

• 한국유기농업학회지
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• 제23권4호
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• pp.781-796
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• 2015

시설채소 무경운 유기재배와 분할관수 효과를 구명하고자 시험을 수행한 결과 1회 전량 관수한 경운재배 토양의 수분함량은 30 cm 깊이까지 관수개시 후 급격하게 증가 후 다음 관수 직전까지 계속하여 감소되었다. 경운 토양의 수분함량 편차는 토양이 깊어질수록 감소되었다. 1회 전량 관수한 무경운 토양 표토와 지하 20 cm 깊이의 수분함량은 해가 뜨기 시작하면 증가되고 야간에는 감소되는 증발산에 의한 주기적인 일변화를 보였다. 그리고 2회 분할 관수한 경운 표토와 무경운 표토와 지하 20 cm 깊이까지의 수분함량은 증발산에 의한 주기적인 일변화를 나타내었다. 토양의 염류농도는 관수 후 증가되기 시작하여 다음 관수 직전까지 계속하여 감소되었으며, 토양이 깊어질수록 염류농도 증가 시간은 지연되었다. 무경운 표토의 염류농도 오전 11시부터 정오 12시 사이에 증가되기 시작하여 오후 2~6시경을 정점으로 1일 1회 증가와 감소되는 증발산작용에 의한 일변화를 보였다. 30 cm 깊이의 무경운 토양에서는 염류농도의 일변화가 측정되지 않았다. 토양수분 함량과 염류농도는 경운방법에 관계없이 정(+)의 상관관계를 나타내었다. 무경운 토양에서 재배된 고추의 생육은 경운 토양에서 재배된 고추에 비하여 생육이 억제되는 경향을 보였다. 경운방법에 관계없이 50%씩 2회 분할 관수한 토양에서 재배된 고추는 1회 전량관수에 비하여 주지의 길이와 경경 등 생육이 증가되는 경향을 보였다. 고추의 수확과수는 1회 전량관수에 비하여 2회 분할 관수가 경운과 무경운 처리에서 각각 49%와 47% 정도 현저하게 증가되었다. 고추 수량은 무경운 재배가 관행 경운재배에 비하여 8% 정도 증수되었다. 2회 분할관수의 고추 수량이 1회 전량관수에 비하여 수확과수의 증가로 경운 재배에서는 36%, 무경운 재배에서는 39% 정도 현저하게 증수되었다.

• 한국작물학회지
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• 제38권3호
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• pp.290-295
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• 1993

수도 무경기 기계이앙 재배시 수도수량과 토양특성 변화를 구명하기 위하여 무경운을 포함한 논토양 특성에 맞는 최소경운 방법을 확립코자 미사 질식토, 사양토, 미사질양토의 3개 포장에서 경운방법을 달리하여 화성벼를 재배하면서 수도 수량과 토양특성을 조사, 분석한 결과는 다음과 같다. 1. 무경기구의 수온과 지온은 제 일 낮았으나 처리간에 온도차이는 크지 않았다. 2. 토성별 평균감수심은 사양토에서 가장 많았고 미사질식토에서 가장 적었는데 무경윤구의 감수심이 다른 처리구보다 1.4～2.2mm/일 많았다. 3. 수확기때 수도체의 무기함량은 무경기시 다른 처리구에 비하여 미사질식토에서는 $Na_2$O 함량을 제외하고는 가장 높았다. 4. 무경운구의 수양감수는 경운기 경운+로타리구에 비하여 사양토에서 18%, 미사질식토에서 7%, 미사질양토에서 1%감수되었다.

• 한국작물학회지
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• 제60권2호
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• pp.167-173
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• 2015

농경지의 볏짚 수거량이 증가하면서 부족한 유기물을 공급하기 위하여 녹비작물을 이용하고 있다. 녹비작물은 유기물공급과 화학비료 대체가 가능한 우수한 유기물원이다. 그러나 농경지에서 분해되는 과정에 메탄을 발생시키기 때문에 메탄발생량을 줄이기 위한 노력이 요구된다. 따라서 논토양에서 녹비작물을 이용할 때 메탄발생량을 줄이기 위하여 경운깊이를 달리하여 시험하였다. 벼 생육기간 중 메탄 발생량은 이앙 후 63일, 74일에 가장 많았고 이앙 후 74일 이후부터 감소되었으며 이앙 후 106일에는 거의 발생되지 않았다. 녹비종류에 따른 메탄발생량은 보리환원구에서 가장 많았고, 그 다음은 헤어리베치, 화학비료 순이었다. 경운 깊이에 따른 메탄발생량은 10cm경운보다 20 cm로 경운함으로써 화학비료는 22.5%, 헤어리베치 환원구는 12.4%, 보리환원구는 11.7% 감소되었다. 벼 재배기간 동안 대기온도는 $30{\sim}40^{\circ}C$였고, 지온은 대기온도보다 약 $2{\sim}10^{\circ}C$정도 낮았다. 산화환원전위(Eh)는 이앙 전 관개를 시작하면서 급격히 토양이 환원되어 (-)값을 나타냈다. 작물 재배기간 동안 산화환원전위차는 -300~-500 mV으로 낮았으며 관개가 중단된 이앙 후 106일 이후에는 다시 급격하게 증가되었다. 쌀 수량은 경운깊이에 따른 차이는 없었으나 녹비작물중에서는 헤어리베치 환원구에서 가장 많았다. 논토양에서 헤어리베치를 이용할 때 20cm로 경운하여 메탄발생을 효과적으로 줄일 수 있었다.