• 한국작물학회지
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• 제50권4호
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• pp.238-246
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• 2005

Rice yield and protein content have been shown to be highly variable across paddy fields. In order to characterize this spatial variability of rice within a field, two-year experiments were conducted in 2002 and 2003 in a large-scale rice field of $6,600m^2$ In year 2004, an experiment was conducted to know if variable rate treatment (VRT) of N fertilizer, that was prescribed for site-specific management at panicle initiation stage, could reduce spatial variation in yield and protein content of rice while increasing yield compared to conventional uniform N topdressing (UN, 33kg N/ha at PIS) method. VRT nitrogen prescription for each grid was calculated based on the nitrogen (N) uptake (from panicle initiation to harvest) required for target rice protein content of $6.8\%$, natural soil N supply, and recovery of top-dressed N fertilizer. The required N uptake for target rice protein content was calculated from the equations to predict rice yield and protein content from plant growth parameters at panicle initiation stage (PIS) and N uptake from PIS to harvest. This model· equations were developed from the data obtained from the previous two-year experiments. The plant growth parameters for the calculation of the required N were predicted non-destructively by canopy reflectance measurement. Soil N supply for each grid was obtained from the experiment of year 2003, and N recovery was assumed to be $60\%$ according to the previous reports. The prescribed VRT N ranged from 0 to 110kg N/ha with an average of 57kg/ha that was higher than 33 kg/ha of UN. The results showed that VRT application successfully worked not only to reduce spatial variability of rice yield and protein content but also to increase rough rice yield by 960kg/ha. The coefficient of variation (CV) for rice yield and protein content was reduced significantly to $8.1\%$ and $7.1\%$ in VRT from $14.6\%$ and $13.0\%$ in UN, respectively. And also the average protein content of milled rice in VRT showed very similar value of target protein content of $6.8\%$. In conclusion the procedure used in this paper was believed to be reliable and promising method for reducing within-field spatial variability of rice yield and protein content. However, inexpensive, reliable, and fast estimation methods of natural N supply and plant growth and nutrition status should be prepared before this method could be practically used for site-specific crop management in large-scale rice field.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.303-303
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• 2017

Japanese agriculture has faced to several threats: aging and decrease of farmer population, global competition, and the risk of climate change as well as harsh and variable weather. On the other hands, the number of large scale farms is increasing, because farm lands have been being aggregated to fewer numbers of farms. Cost cutting, development of efficient ways to manage complicatedly scattered farm lands, maintaining yield and quality under variable weather conditions, are required to adapt to changing environments. Information and communications technology (ICT) would contribute to solve such problems and to create innovative technologies. Thus we have been developing an early warning and decision support system to reduce weather and climate risks for rice, wheat and soybean production in Japan. The concept and prototype of the system will be shown. The system consists of a weather data system (Agro-Meteorological Grid Square Data System, AMGSDS), decision support contents where information is automatically created by crop models and delivers information to users via internet. AMGSDS combines JMA's Automated Meteorological Data Acquisition System (AMeDAS) data, numerical weather forecast data and normal values, for all of Japan with about 1km Grid Square throughout years. Our climate-smart system provides information on the prediction of crop phenology, created with weather forecast data and crop phenology models, as an important function. The system also makes recommendations for crop management, such as nitrogen-topdressing, suitable harvest time, water control, pesticide spray. We are also developing methods to perform risk analysis on weather-related damage to crop production. For example, we have developed an algorism to determine the best transplanting date in rice under a given environment, using the results of multi-year simulation, in order to answer the question "when is the best transplanting date to minimize yield loss, to avoid low temperature damage and to avoid high temperature damage?".

• 한국토양비료학회지
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• 제30권2호
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• pp.114-121
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• 1997

본 연구(硏究)는 2년간 ('95~'96) 벼 무논골뿌림직파재배시(直播栽培時) 완효성비료(緩效性肥料) (LCU)의 시용량(施用量) 및 분시방법(分施方法)에 따른 시비질소(施肥窒素)의 토양중 $NH_4-N$발현량(發現量), 질소흡수량(窒素吸收量) 및 이용율(利用率)에 미치는 영향과 수량성(收量性) 변이(變異)를 조사하기 위하여 호남평야지(湖南平野地)의 대표토양(代表土壤)인 전북통(全北統)에서 시험한 결과로서 다음과 같이 요약할수 있다. 1. 완효성비료(緩效性肥料)는 생육초기(生育初期) 기온(氣溫)이 높으면 질소(窒素)가 조기(早期)에 용출(溶出)되었고, 최고분얼기(最高分蘖期)의 시비질소(施肥窒素) 이용율(利用率)은 절반으로 감소(減少)되었다. 2. 수도체(水稻體)의 질소흡수량(窒素吸收量)과 질소이용율(窒素利用率)은 관행시비량(慣行施肥量)의 완효성비료(緩效性肥料)를 전량기비(全量基肥)로 시용한것보다 관행시비량의 20%감비(減肥) 그중 60%를 완효성비료(緩效性肥料)로 기비(基肥)에 시용하고 요소(尿素) 40%를 수비(穗肥)로 시용(施用)한 구(區)에서 월등히 높았다. 3. 정조(正租)로의 질소(窒素) 전이율(轉移率)은 기온(氣溫)이 높은 해에 증가(增加)하였으나 단비(單肥)(요소(尿素))시용구(施用區)에서 완효성비료(緩效性肥料) 시용구(施用區)보다 높았다. 4. 완효성비료(緩效性肥料)를 전량(全量) 내지 20%감비(減肥)하여 80%를 전량기비(全量基肥)로 시용시(施用時) 기온(氣溫)이 높은 해는 유효분얼수(有效分蘖數)와 수수(穗數)가 감소(減少)되어 수량(收量)이 크게 감소(減少)되었다.

• 한국환경복원기술학회지
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• 제6권5호
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• pp.40-47
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• 2003

본 연구는 난지형 잔디인 버뮤다그래스와 한지형 잔디인 켄터키블루그래스 혹은 톨페스큐와의 혼식에 의한 내답압성의 향상효과를 검토하였다. 또한, 내답압성에 미치는 고무칩의 효과 및 한국잔디류(Zosia spp.)의 답압에 대한 품종간의 차이 등을 조사하였다. 여름철의 답압 실험에서는 버뮤다그래스 단식구보다 한지형잔디의 혼식구가 지상부의 녹엽면적율이 높게 유지하고 있었다. 또한 겨울철의 답압 실험에서는 버뮤다 단식구는 나지화가 크게 진행하였으나, 한지형 잔디와의 혼식구에서는 전혀 나지화 현상이 발생하지 않았다. 겨울철의 답압 처리 후 토양의 가비중을 조사한 결과, 버뮤다그래스 단식구에서는 증가하였지만, 한지형 잔디와의 혼식구에서는 증가하지 않았다. 이상의 결과로부터 난지형 잔디와 한지형 잔디를 혼식함으로써 연간을 통하여 잔디의 내답압성 향상 효과가 나타났다. 또한 잔디의 손상을 완화하는 물리적 보조수단인 고무칩을 지표면에 산포하는 방법도 내답압성을 향상시키고 있는 것으로 나타났다. 이처럼 단기간의 답압실험에서도 단식구와 혼식구, 품종 및 고무칩 산포에 의한 차이를 보이고 있어, 좀더 다양한 방법으로 장기간에 걸친 답압실험이 이루어져야할 것이다.

• 한국농림기상학회지
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• 제3권4호
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• pp.177-184
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• 2001

본 연구는 벼 휴립건답직파 절수재배에 알맞은 질소 수비량을 구명하고자 파종량을 6kg/10a과 10kg/10a으로 하고, 질소 수비 시비량을 10a당 4.8kg(표준구), 2.4kg, 7.2kg 및 9.6kg을 시비 처리하여 시험한 결과를 요약하면 다음과 같다. 가. 질소 수비량이 많을수록 엽면적지수와 지상부 건물중은 약간씩 증가하는 경향이었다. 나. 출수기 광합성능은 질소 수비량이 많을수록 높았으며, 파종량간에는 6 kg/10a 파종에서 높았다. 다. 질소의 흡수량은 질소 수비량이 많을수록 많았으며, 질소 이용율은 6kg/10a 파종에서는 질소 표준수비(4.8kg/10a) 보다 50% 증시에서 가장 높았고 10 kg/10a 파종에서는 별 차이가 없었다. 라. 단위 면적당 수수는 질소 수비량이 많을수록 많았고, 등숙비율과 현미 천립중은 비슷하여, 쌀 수량은 표준(6kg/10a 파종시 수비량 4.8kg/10a 시용) 보다 50%증시(7.2kg/ha)구에서 6kg/10a 파종에서는 6%, 10 kg/10a 파종에서는 13% 증수되었다.

• 한국작물학회지
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• 제50권1호
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• pp.16-21
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• 2005

This study was conducted to establish the elaborate nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy. The nitrogen uptake by rice plants was insignificant until 25 days after seeding, and increased gradually thereafter. During this early growth stage, rice plants absorbed only the $4\%$ of basal applied N, while the $45\%$ of N fertilizer remained in the paddy soil. The absorption of basal N by rice plants was almost completed at 46 days after application. Nitrogen top-dressed at 5-leaf stage was well matched to crop nutrient demand, so it could be absorbed so actively in 8days after application. As a result, we could cut down the amount of N fertilizer to $36\%$ of the basal N level without significant difference in yield. Plant recoveries of fertilizer $^{15}N$ applied with different application timings were $7.8\%$ for basal, $9.4\%$ for 5-leaf stage, $17.1\%$ for tillering stage, and $23.4\%$ for panicle initiation stage, respectively. When urea was applied with nitrogen fertilization practice based on basal incorporation (BN), plant recovery of $^{15}N$ at harvest was $31.0\%$, which was originated from $13.7\%$ for grain, and $21.3\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. Plant recovery of fertilizer $^{15}N$ applied with nitrogen fertilization practice based on topdressing at 5-leaf stage (TN), where N rate was reduced by $18\%$ compared with BN, was $35.1\%$ (grain $15.6\%$), and $19.9\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. TN showed a higher $^{15}N$ recovery than BN because it was to apply N fertilizer at a time to well meet the demand of rice plant direct-seeded on flooded paddy. We concluded that TN would be the nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2005년도 국제학술회의
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• pp.57-74
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• 2005

Rice yield and protein content have been shown to be highly variable across paddy fields. In order to characterize this spatial variability of rice within a field, the two-year experiments were conducted in 2002 and 2003 in a large-scale rice field of $6,600m^2$ In year 2004, an experiment was conducted to know if prescribed N for site-specific fertilizer management at panicle initiation stage (VRT) could reduce spatial variation in yield and protein content of rice while increasing yield compared to conventional uniform N topdressing (UN, ,33 kg N/ha at PIS) method. The trial field was subdivided into two parts and each part was subjected to UN and VRT treatment. Each part was schematically divided in $10\times10m$ grids for growth and yield measurement or VRT treatment. VRT nitrogen prescription for each grid was calculated based on the nitrogen (N) uptake (from panicle initiation to harvest) required for target rice protein content of $6.8\%$, natural soil N supply, and recovery of top-dressed N fertilizer. The required N uptake for target rice protein content was calculated from the equations to predict rice yield and protein content from plant growth parameters at panicle initiation stage (PIS) and N uptake from PIS to harvest. This model equations were developed from the data obtained from the previous two-year experiments. The plant growth parameters for this calculation were predicted non-destructively by canopy reflectance measurement. Soil N supply for each grid was obtained from the experiment of year 2003, and N recovery was assumed to be $60\%$ according to the previous reports. The prescribed VRT N ranged from 0 to 110kg N/ha with average of 57kg/ha that was higher than 33kg/ha of UN. The results showed that VRT application successfully worked not only to reduce spatial variability of rice yield and protein content but also to increase rough rice yield by 960kg/ha. The coefficient of variation (CV) for rice yield and protein content was reduced significantly to $8.1\%\;and\;7.1\%$ in VRT from $14.6\%\;and\;13.0\%$ in UN, respectively. And also the average protein content of milled rice in VRT showed very similar value of target protein content of $6.8\%$. Although N use efficiency of VRT compared to UN was not quantified due to lack of no N control treatment, the procedure used in this paper for VRT estimation was believed to be reliable and promising method for managing within-field spatial variability of yield and protein content. The method should be received further study before it could be practically used for site-specific crop management in large-scale rice field.

• 한국초지조사료학회지
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• 제25권1호
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• pp.1-6
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• 2005

With recent interest organic farming the use of legumes including vetch and clover to provide N to adjacent crops is increasing in Korea. In the present studies, we conducted a trial to investigate the effects of the application of N rate on nitrogen fixation and transfer from vetch to barley in mixed stands. The experiment was arranged in a randomized complete block design with three replications. Four different N rates(0, 75, 113 and 150/ha) was used and vetch+barley was broadcasted manually on 1.5 $\times$2 m plot in Oct. 2001. Half of urea and K$_{2}O, 200 Phosphate and 75 kg potash per ha were applied as basal dressing md half of N md 75 potash were used for topdressing to soil surface on MarctL 2002. The equivalent of 1kg ha$^{-1}$ at($^{15}$NH$_{4}$)$_{2}$SO$_{4}$ solution at 99.8 atom $\%$$^{15}$N excess was applied to the microplot in mid April. Forage was harvested from each plot at ground level and separated into barley and vetch. Total N content and It values of samples were determined using a continuous flow stable isotope ratio mass spectrometry(IsoPrime-EA. Micromass, UK.). The percentage of legume H fixed from atmospheric N2 were 95.0, 93.8, 94.4 and $84.8\%$ with increment of N levels. The percentage of N transfer from vetch to barley by N-difference method with increment of N fertilizer were from 58 to$49\%$ while 39 to $23\%$ in $^{15}$N-dilution method. The amount of transfer from vetch to barley were 87 to 68 kg/ ha with N level by N-difference moth여 and 58 to -56/ha with N application levels by $^{15}$N dilution method. The amount of nitrogen fixation per ha were from 150 kg / ha to 219 kg / ha by different method, but on the other side 49 to 105kg/ha by N$^{15}$-dilution.

• 유기물자원화
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• 제27권3호
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• pp.41-48
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• 2019

유기질 비료 중 혼합유박은 작물생산성과 토양의 비옥도를 높일수 있는 농자재중 하나이다. 그러나 배추 재배시 혼합유박의 적정시용량에 대한 연구는 미비한 실정이다. 이에 본 연구는 혼합유박의 밑거름 시용량에 따른 배추의 생육, 수량 및 토양특성 변화를 확인하고 이를 통해 혼합유박의 밑거름 적정 시용량을 제시하고자 하였다. 본 시험은 무처리, NPK처리구($N-P_2O_5-K_2O$ : $320-78-198kg\;ha^{-1}$), 혼합유박 처리구는 밑거름을 질소기준 $210kg\;ha^{-1}$을 50, 100 및 150% 수준으로 기비하고 추비는 시기에 맞게 시비하는 것으로 설정하였다. 배추의 생육은 무처리구를 제외하고는 통계적 유의성은 없었으나, 수량의 경우 NPK 처리구 > MEC 150% 처리구 > MEC 100% 처리구 > MEC 50% 처리구 > 무처리구 순이었다. 처리구에 따른 질소 이용 효율은 혼합유박 처리량이 증가할수록 증가하는 경향이었다. 토양 특성의 경우 pH, OM, $Av.P_2O_5$, $NH_4-N$ 및 Ex.K의 경우 유의적인 차이는 없었으나 EC 및 $NO_3-N$은 혼합유박의 밑거름 시용량이 증가할수록 약간 증가하는 추세였다. 이를 통해 수량을 위한 혼합유박 밑거름 적정시용량은 밑거름 150% 처리인 것으로 판단된다.

• 한국가금학회지
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• 제29권4호
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• pp.265-270
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• 2002

본 연구에서는 ALUM을 처리한 영향이 3주령과 6주령 병장아리 성장과 6주후 깔짚 중의 질소(N)함량이 어떻게 영향을 미치는지 비교시험을 하였다. 비교를 한2개 처리 구는 전부 단백질 수준을 같게 하고 한 처리구에서는 깔짚에 ALUM을 처리 하고(T$_1$) 다른 처리구에는 깔짚에 ALUM을 처리하지 않았다(T2). 이때 깔짚은 왕겨로 하였으며, ALUM 처리는 왕겨kg당 200 g을 topdressing 하였다. 사료섭취량은 22~42일령과 0~42일령에서 공히 T$_1$구가 T$_2$구보다 높았다(P<0.05). 그리고 체중증가량은 0~42일령에서 T$_1$구가 T$_2$구보다훨씬 높았으나(P<0.01) 사료효율에는 차이가 없었다. 왕겨로부터 발생되는 암모니아 농도는 처음 5주 동안은 T$_1$구가 T$_2$구보다 유의하게(P<0.05 나 P<0.01) 낮았으나 6주부터는 T$_1$구와 T$_2$구 간에는 차이가 없었다. 또 6주령에서 측정한 왕겨내의 pH는 T$_1$구가 T$_2$구보다 낮았으며P<0.05), 켈달 질소 함량(TKN)은 T$_1$구가 T$_2$구보다 높았다 (P<0.05). 그러나 왕겨내의 NH$_4$-N및 NO$_3$-N의 함량은 T$_1$과 T$_2$에서는 차이가 없었다. 본 연구 결과를 다시 정리하면 깔짚에 ALUM을 처리할 경우 6주령에서 육계의 생산성은 기대되며 암모니아 생성량의 감소는 기대하지 못하지만 깔짚은 질소비료로서의 성분은 유효함을 알 수 있다.