• 한국환경농학회지
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• 제41권3호
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• pp.167-176
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• 2022

BACKGROUND: Nitrogen (N) is an important element for turfgrass (Zoysia matrella) growth; however, standard N application rate for turfgrass is not established yet. This study was conducted to evaluate the effect of N application rates on the growth and quality of turfgrass for establishment of standard N application rate. METHODS AND RESULTS: Treatments were as follows; control (0 N g/m²/month), 1N (1 N g/m²/month), 2N(2 N g/m²/month), 3N (3 N g/m²/month), 4N (4 N g/m²/month), and 5N (5 N g/m²/month). N application improved visual turfgrass quality. Compared with the control, clipping yield of all N treatments increased by 90~194%. The grass shoot weight of 3N, 4N, and 5N treatments increased by 52%, 43%, and 111%, respectively, and the stolon weight of 4N and 5N treatments increased by 412% and 201%, respectively, compared to the control. The N uptake amount and N recovery rate were estimated to be 4.10~6.28 g/m² and 14~58%, respectively. CONCLUSION(S): These results indicate that considering visual quality, clipping yield, N uptake amount, and N recovery, the application rate of 2~3 N g/m²/month was suggested to be suitable for Z. matrella production.

• Journal of Biosystems Engineering
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• 제42권2호
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• pp.98-103
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• 2017

Purpose: Precision agriculture includes determining the right amount of nitrogen for a specific location in the field. This work focused on developing and validating a model using variable rate nitrogen application based on the estimated SPAD value from the ground-based image sensor. Methods: A variable rate N application based on the decision making system was performed using a sensor-based variable rate nitrogen application system. To validate the nitrogen application decision making system based on the SPAD values, the developed N recommendation was compared with another conventional N recommendation. Results: Sensor-based variable rate nitrogen application was performed. The nitrogen deficiency level was measured using the image sensor system. Then, a variable rate application was run using the decision model and real-ti me control. Conclusions: These results would be useful for nitrogen management of corn in the field. The developed nitrogen application decision making system worked well, when considering the SPAD value estimation.

• 한국토양비료학회지
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• 제50권6호
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• pp.574-587
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• 2017

Excessive application of nitrogen (N) fertilizer to support switchgrass growth for bioenergy production may cause adverse environmental effects. The objective of this study was to determine optimum N application rate to increase biomass yield of switchgrass and to reduce adverse environmental effects related to N. Switchgrass was planted in May 2008 and biomass yield, N uses of switchgrass, nitrate ($NO_3$) leaching, and nitrous oxide ($N_2O$) emission were evaluated from 2010 through 2011. Total N removal significantly increased with N rate despite the fact that yield did not increased with above $56kg\;N\;ha^{-1}$ of N rate. Apparent nitrogen recoveries were 4.81 and 5.48% at 56 and $112kg\;N\;ha^{-1}$ of N rate, respectively. Nitrogen use efficiency decreased into half with increasing N rate from 56 to $112kg\;N\;ha^{-1}$. Nitrate leaching and $N_2O$ emission were related to N use of switchgrass. There was no significant difference of cumulative $NO_3$ leaching between 0 and $56kg\;N\;ha^{-1}$ but, it significantly increased at $112kg\;N\;ha^{-1}$. There was no significant difference of cumulative $N_2O$ emission among N rates in crest, but it significantly increased at $112kg\;N\;ha^{-1}$ in toe. Excessive N application rate (above $56kg\;N\;ha^{-1}$) beyond plant requirement could accelerate $NO_3$ leaching and $N_2O$ emission in switchgrass field. Overall, $56kg\;N\;ha^{-1}$ might be optimum N application rate in reducing economic waste on N fertilizer and adverse environmental impacts.

• 한국환경농학회지
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• 제30권2호
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• pp.99-104
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• 2011

BACKGROUND: Application of urea may increase $CO_2$ emission from soils due both to $CO_2$ generation from urea hydrolysis and fertilizer-induced decomposition of soil organic carbon (SOC). The objective of this study was to investigate the effects of increasing urea application on $CO_2$ emission from soil and mineralization kinetics of indigenous SOC. METHODS AND RESULTS: Emission of $CO_2$ from a soil amended with four different rates (0, 175, 350, and 700 mg N/kg soil) of urea was investigated in a laboratory incubation experiment for 110 days. Cumulative $CO_2$ emission ($C_{cum}$) was linearly increased with urea application rate due primarily to the contribution of urea-C through hydrolysis to total $CO_2$ emission. First-order kinetics parameters ($C_0$, mineralizable SOC pool size; k, mineralization rate) became greater with increasing urea application rate; $C_0$ increased from 665.1 to 780.3 mg C/kg and k from 0.024 to 0.069 $day^{-1}$, determinately showing fertilizer-induced SOC mineralization. The relationship of $C_0$ (non-linear) and k (linear) with urea-N application rate revealed different responses of $C_0$ and k to increasing rate of fertilizer N. CONCLUSION(s): The relationship of mineralizable SOC pool size and mineralization rate with urea-N application rate suggested that increasing N fertilization may accelerate decomposition of readily decomposable SOC; however, it may not always stimulate decomposition of non-readily decomposable SOC that is protected from microbial decomposition.

• Asian-Australasian Journal of Animal Sciences
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• 제29권8호
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• pp.1129-1135
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• 2016

Whole-crop wheat (Triticum aestivum L.) as forage has been extensively used in the world. In this study, the effects of N application rates on the yields, nutritive value and silage quality were investigated. The N application rates were 0, 75, 150, 225, and 300 kg/ha. The research results indicated that the dry matter yield of whole-crop wheat increased significantly with increasing N rate up to 150 kg/ha, and then leveled off. The crude protein content and in vitro dry matter digestibility of whole-crop wheat increased significantly with increasing N up to 225 kg/ha, while they no longer increased at N 300 kg/ha. On the contrary, the content of various fibers tended to decrease with the increase of N application. The content of lactic acid, acetic acid and propionic acid in silages increased with the increase of N rate (p<0.05). The ammonia-N content of silages with higher N application rates (${\geq}225kg/ha$) was significantly higher than that with lower N application rates (${\leq}150kg/ha$). Whole-crop wheat applied with high levels of N accumulated more nitrate-N. In conclusion, taking account of yields, nutritive value, silage quality and safety, the optimum N application to whole-crop wheat should be about 150 kg/ha at the present experiment conditions.

• 한국약용작물학회지
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• 제11권2호
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• pp.109-114
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• 2003

제주도에서 쇠무릎의 뿌리와 포과의 생산을 위한 적정질소시비량을 구명하고자 재식밀도(50, 100주/$m^2$, 1주 2본)와 질소시비량(0, 6, 12, 18, 24, 30 kg/10a)에 따른 생육, 건물수량, 지상부 질소 함량 및 수량 등을 조사하였던 바 그 결과를 요약하면 다음과 같다. 조사한 모든 형질에 대하여 재식밀도와 질소시비량 간에는 상호작용이 없었다. 100주/$m^2$ 재식구에 비하여 50주/$m^2$ 재식구에서 주근장 및 뿌리수는 각각 5%와 52%증가되었고 경엽의 질소함량은 다소 낮았으나 다른 형질에서는 차이가 없었다. 질소시비량은 주경직경, 주당 화서수, 화서당 포과수, 주근장, 주근직경, 포과 질소함량에 영향을 미치지 않았다. 질소시비량이 10a당 0 kg에서 30kg으로 증가함에 따라 SPAD 값은 35.0에서 40.5로, 경엽의 질소함량은 1.09%에서 1.38%로 직선적으로 증가되었다. 질소시비량은 초장, 주당 분지수, 포과 뿌리 건물수량, 주당 근수, 경엽질소수량에 대해서는 2차함수식으로, 주당 화서수에 대해서는 3차함수적인 관계로 분석되었다. 이러한 분석결과 포과 및 뿌리 건물수량이 최대가 되는 질소시비량은 21kg/10a로 추정되었다.

• Agricultural and Biosystems Engineering
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• 제7권1호
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• pp.18-26
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• 2006

In-field site-specific nitrogen (N) management increases crop yield, reduces N application to minimize the risk of nitrate contamination of ground water, and thus reduces farming cost. Real-time N sensing and fertilization is required for efficient N management. An 'on-the-go' site-specific N management system was developed and evaluated for the supplemental N application to com (Zea mays L.). This real-time N sensing and fertilization system monitored and assessed N fertilization needs using a vision-based spectral sensor and controlled the appropriate variable N rate according to N deficiency level estimated from spectral signature of crop canopies. Sensor inputs included ambient illumination, camera parameters, and image histogram of three spectral regions (red, green, and near-infrared). The real-time sensor-based supplemental N treatment improved crop N status and increased yield over most plots. The largest yield increase was achieved in plots with low initial N treatment combined with supplemental variable-rate application. Yield data for plots where N was applied the latest in the season resulted in a reduced impact on supplemental N. For plots with no supplemental N application, yield increased gradually with initial N treatment, but any N application more than 101 kg/ha had minimal impact on yield.

• 한국초지조사료학회지
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• 제22권1호
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• pp.37-44
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• 2002

본 연구는 가축분뇨의 시용수준과 이의 효과를 증진시키기 위한 추가적인 화학비료 시용수준이 사료작물의 생산성과 이에 의한 환경오염에 미치는 영향에 대한 것으로써, lysimeter에서 옥수수에 대한 액상발효우분 시용수준과 추가적인 요소N의 시용수준에 따라 질소의 이용효율과 함께 NO$_3$$^{-}$의 용탈에 의한 환경오염에 미치는 영향을 정확히 규명, 가축분뇨의 자원화는 물론 가축분뇨에 의한 환경오염 방지대책 수립을 하고자 수행하였는데 그 결과는 다음과 같다. 1. 옥수수의 건물수량은 액상발효우분 및 요소 시용수준이 증가함에 따라 비례적으로 증가하였다. 2. 옥수수 중의 전질소 함량은 액상발효우분 및 요소의 시용수준이 증가함에 따라 증가를 하였다. 3. 용탈수 중의 NO$_3$$^{-}$ 함량은 평균 7.58ppm (6.27~9.02ppm)으로 매우 낮았고 시용수준간에도 차이가 거의 없었다. 그러나 강우량이 높은 시기에 NO$_3$￣의 용탈 함량도 증가하였다.

• 한국작물학회지
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• 제38권3호
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• pp.235-239
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• 1993

모시풀 재배에 있어서의 적정 시비량을 알고자 휴지재식 초년부터 성원이된 4년째까지 시험조사한 결과를 요약하면 다음과 같다. 1. 모시풀의 경신장에는 비료 3요소중 질소, 칼리의 증시효과가 컸고, 석회도 경신장에 크게 작용하는 것으로 생각되었다. 2. 기준시비량 $P_2O_5$-$K_2$O=9-3-9kg/10a에 비하여 질소는 2～3배, 칼리는 2배비 시용에서 수량이 증대되었고, 그 중 10a당 질소 18kg, 인산 3kg, 칼리 18kg와 석회 200kg 시용의 경우 가장 유효경 비율도 높았으며 조섬유 수량에서도 33% 증수되었다.

• 한국토양비료학회지
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• 제16권3호
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• pp.274-279
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• 1983

미원유기질비료(味元有機質肥料)의 시용(施用)이 인삼(人蔘)의 발아(發芽)와 생육(生育) 및 토양(土壤)의 이화학성(理化學性)에 미치는 영향을 조사(調査)하여 연구(硏究) 검토(檢討)한 결과(結果)는 다음과 같다. 1. 인삼종자(人蔘種子)의 발아율(發芽率)은 대조구(對照區)에 비(比)하여 미원(味元) 유기질비료(有機質肥料)를 질소성분량(窒素成分量)으로 10a당(當) 2.5kg, 5kg, 10kg을 처리(處理)한 구(區) 순(順)으로 양호(良好)하였으며 15kg을 시용(施用)한 구(區)는 대조구(對照區)와 비슷하였다. 2. 묘삼(苗蔘)의 결주율(缺株率)은 질소성분량(窒素成分量)으로 10a당(當) 15kg 시용(施用)한 구(區)가 가장 높았고 또한 묘삼(苗蔘)의 생육(生育)도 불량(不良)하였다. 10kg구(區)는 대조구(對照區)와 비슷하였으며 2.5kg, 5kg의 순(順)으로 결주율(缺株率)이 낮아서 5kg/10a구(區)가 가장 양호(良好)하였다. 3. 묘삼(苗蔘)의 근중(根重)은 10kg구(區)와 5kg처리구(處理區)에서 비슷하게 가장 무거운 중량(重量)을 나타내어 다른 처리구(處理區)에 비(比)하여 유의성(有意性) 있는 증가(增加)를 보였으나 2.5kg, 대조구(對照區), 15kg처리구(處理區)의 순(順)으로 묘삼(苗蔘)의 중량(重量)이 가벼웠으며 수량(收量)도 적었다. 4. 미원유기질비료(味元有機質肥料)의 시용량(施用量)과 균삼채굴전(菌蔘採掘前) 후(後) 각(各) 처리구토양(處理區土壤)의 리화학적성질(理化學的性質)을 비교(比較) 검토(檢討)한 결과(結果) 다른 성질(性質)은 큰 변화(變化)가 없었으나 C.E.C. 및 유기물함량(有機物含量)은 증가(增加)하였다. 유기질비료(有機質肥料) 시용량(施用量)과 $NO_3-N$량(量)은 고도(高度)의 정상관(正相關)을 나타냈다. 5. 인삼(人蔘)의 발아율(發芽率)과 결주율(缺株率) 그리고 근중면(根重面)에서 고찰(考察)하여보면 산야초퇴비(山野草堆肥)의 양(量)을 질소성분량(窒素成分量)으로 20kg/10a 및 미원유기질비료(味元有機質肥料)를 성분량(成分量)으로 10kg/10a을 시용(施用)하는 것이 묘삼재배(苗蔘栽培)에 있어서 가장 좋은 것으로 생각된다.