• Environmental and Resource Economics Review
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• v.8 no.1
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• pp.51-73
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• 1998

조건부가치측정법(CVM)의 지불의사 유도방법인 이중 양분선택형 질문법은 단일 양분선택형 질문 CV자료의 통계적 비효율성을 극복하기 위한 방법으로 제안되었다. 이 방법은 여러 가지 장점에도 불구하고 출발점 편의의 심리학적 근거인 정박효과 (anchoring effect)의 발생 가능성을 의심받고 있다. 그러므로 본 논문에서는 이중 양분선택형 질문 CV자료에서 정박효과를 검토할 수 있는 일반적 지불의사금액모형을 제시하고, 그 모형으로부터 정박효과를 검토할 수 있는 방법을 제안한다. 모형은, Cameron and Quiggin(1994)이 제안한 이변량 모형에 두 번째 내재 지불의사금액의 설명변수로서 처음 제시된 특정금액에 대한 양분선택적 응답결과를 포함시킨 형태이다. 이 모형에서 처음 제시된 특정금액에 대한 양분선택적 응답결과의 계수 부호가 음(-)이고 통계적으로 유의하다면 정박효과가 발생하는 것으로 볼 수 있다. 그러나 만약 이러한 계수 검토에서 정박효과 발생을 확인할 수 없는 경우, 두 번의 응답에서 두 지불의사금액 추정치들의 평균이 다르다고 볼 수 없다면 정박효과를 우려할 필요가 없다. 이 검토 모형 및 방법을 본 연구에서 한강 수질 개선에 대한 CV자료에 적용해 본 결과 정박효과를 우려할 필요가 없음을 확인할 수 있다.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.328-335
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• 2023

For appropriate nutrient management and enhanced plant growth, soil sensors which reflect soil nutrient levels are required. Because there is no available sensor for nutrient monitoring, electrical conductivity (EC) sensor can be used to evaluate soil nutrient levels. Soil nutrient management using EC sensors would be possible by understanding the relationship between sensor EC values and soil temperature, moisture, and nutrient content. However, the relationship between soil sensor EC values and plant available nutrients was not investigated. Therefore, the objectives of the study were to evaluate effect of different amount of urea on soil EC monitored by sensors during pepper and broccoli cultivation and to predict the plant available nutrient contents in soil. During the cultivation period, soil was collected periodically for analyzing pH and EC, and the available nutrient contents. The sensor EC value increased as the moisture content increased, and low fertilizer treated soil showed the lowest EC value. Principal component analysis was performed to determine the relationship between sensor EC and available nutrients in soil. Sensor EC showed a strong positive correlation with nitrate nitrogen and available Ca. In addition, sum of available nutrients such as Ca, Mg, K, P, S and N was positively related to the sensor EC values. Therefore, EC sensors in open field can be used to predict plant available nutrient levels for proper management of the soil.

• Journal of Korean Society of Forest Science
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• v.85 no.4
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• pp.656-666
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• 1996

Aspen demand has increased recently in the Great Lakes region in the United States. Since aspen has moved into the region in late 1800's, its growing stock has increased so as to change forestry industry of the Lake States. Intensive timber harvesting and biomass removal may cause nutrient depletion, especially on nutrient-poor sites. Forest nutrients and nutrient cycling were investigated in aspen stands of 7-10, 27-33, and 41-42 year-old growing on sandy soils in Minnesota. Nutrients added to the aspen stands by atmospheric deposition and soil weathering were efficiently absorbed and stored in the tree biomass. Aboveground biomass increased from $24.4t{\cdot}ha^{-1}$ at young stands to $139.2t{\cdot}ha^{-1}$ at mature stands. Nutrients accumulated in the tree biomass showed same magnitude of difference. Nutrients added to the site through atmospheric deposition were in the order of Ca, N, K, Mg, and P. Annual litterfall was greater in older stands. However, the amount of nutrients returned by litterfall was not significantly different among stand ages due to the greater nutrient contents in the litterfall of young stands. Litter decomposition and nutrient release rates were greater at young stands than at older stands. Likewise, nutrient availability was higher in young aspen stands and became lower as the stands grew older. Nutrient leaching loss was minimal at all stand ages. Soil N mineralization was greater at young stands than at older stands. Nutrient cycling process was facilitated in young aspen stands with an increased level of available nutrients, Based on the estimations of nutrient balance and nutrient removal by harvesting, Ca was the most critical element which was likely to be depleted if aspen stands are intensively harvested with short rotations.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.89-95
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• 2020

Livestock facilities in Korea are on their way of enlargement resulting in increment of livestock manure. When the livestock manure treated inappropriate way during application to the agricultural area, environmental damage can be occurred such as bad smell, water and air pollution. Therefore it is important to make a good management plan for livestock manure treatment. In order to effectively apply organic fertilizer made by livestock manure in terms of quantity and quality, the current status of nutrient in agricultural land should be calculated quantitatively by scientific way. The OECD suggest member countries to calculate the nutrient balance as an agricultural environment indicator which represents the difference between nutrient inputs and outputs of the amount of nutrients in various ways. In this paper, we calculated the nutrient balances according to three cities which have different characteristics such as urban or rural areas. To reduce the nutrient balance, we considered how to reduce the amount of chemical fertilizer by using organic fertilizer made by livestock manure. And public treatment facilities for livestock manure can be a good solution except civil complaints for location selection. Among the options, manure fertilizer application to the agricultural area for cultivation of forage crops was mainly considered to reduce the nutrient balance by decreasing input of chemical fertilizers and increasing output of crop production. Using the field monitoring data, it can be calculated that the daily nitrogen reductions by 116.5 kg/ha and the daily phosphorus increments by 2.7 kg/ha.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.307-307
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• 2009

우리나라에서 농가단위 경축순환농업 모델에 대한 조사와 농장내 순환구조에서 양분수지를 조사한 사례도는 미미한 실정이다. 이에 경축연계 자원순환 유기농업농가의 실천사례 발굴하고, 실천모델별 축산형태 및 경종형태를 조사하여 경종부분의 양분순환과 양분수지를 조사하고자 하였다. 발굴된 농가단위 경축순환농업 사례는 3가지 형태로 모두 한우를 11~21두 범위에서 사육하는 동시에 $15,510m^2$의 밭농사를 수행하는 농가, $8,019m^2$의 밭농사와 $8,250m^2$ 논농사를 동시에 수행하는 농가, $26,400m^2$의 논농사만 수행하는 농가들이었다. 각 모델에서 배합사료는 모두 외부에서 구입하고 있었으며 조사료의 자급율은 25 ~ 100%인 것으로 조사되었다. 특히, 한우 20두와 논농사 $26,400m^2$를 경영하는 농가에서 조사료(볏짚)의 100%를 자급하였고 동시에 한우사육과정에서 발생한 자급퇴비를 전량 논농사에 사용하여 유기농 벼농사를 유지하고 있었다. 밭농사를 함께 수행하는 농가에서는 자급퇴비 외에 외부로부터 유박비료 및 발효유기질비료를 구입하여 양분을 충당하고 있었다. 각 농가의 토양이화학성을 분석한 결과 pH는 5.49~7.61, 유기물 함량은 1.37~1.40%, 유효인산 함량 253.32~329.63 mg/kg, 칼륨 0.24~0.3, 칼슘 3.97~10.1, 마그네슘 0.89~1.77 $Cmol^+$/kg, CEC는 7.92~11 $Cmol^+$/kg 이었므며 토양내 잔류농약은 검출되지 않았다. 농가별로 발생한 우분퇴비의 성분 분석결과는 전질소 0.68 ~ 0.73%, 전인산 0.68 ~ 0.86%, 칼륨 0.70~0.78% 수준이었다. 각 사례농가별 투입한 실제시비량, 토양분석결과와 사용된 자재의 성분 분석결과를 이용한 시비처방법에 따른 시비량 및 표준시비법에 따른 시비량을 산출하여 3요소의 양분수지를 계산하였다. 이와 함께 유기질비료의 무기화율을 감안한 시비량도 산출하였다. 양분수지를 분석한 결과 3농가 모두 실제시비량은 3요소 모두 초과 되는 것으로 나타났으며, 특히 인산과 칼륨이 2배정도 초과되는 경향을 보였다. 그러나 투입된 자급퇴비 및 유기질비료의 무기화율을 감안한 시비량으로 환산할 경우에는 질소성분이 3농가 모두 부족한 것으로 산출되었으며, 인산과 가리 성분은 충분하거나 초과되는 것으로 계산되었다. 농장내 축산경영을 통해 발생하는 자급퇴비만을 이용할 경우에 경종부문의 양분수지를 산출한 결과를 보면 실제시비량 기준으로 질소는 56~186%, 인산은 90~346%, 칼륨은41~221%로 양분수지가 달라졌으며, 무기화를 감안한 기준으로는 질소는 16~53%, 인산은 52~197%, 칼륨은 41~221%로 양분수지가 달라졌다. 소규모 유기농가단위 경축연계 자원순환 모델 연구를 통해 유기경종농업이 유지될 수 있으나, 3요소별 양분수지의 불균형이 발생할 수 있는 것으로 조사되었으며, 유기질비료의 특성상 무기화율을 감안한 시비량을 적용할 경우에는 질소 성분의 부족과 동시에 인산, 칼륨 성분의 과다가 예측되었다. 따라서 이러한 성분의 불균형을 조정할 시비체계 연구가 필요한 것으로 판단되었다. 본 연구는 농촌진흥청의 "유기가축사양 및 유기 순환체계모델" 연구사업의 세부과제로 수행한 1년차 결과입니다.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.11a
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• pp.176-177
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• 2001

분화용 베고니아 유묘기의 양분흡수 특성을 구명하기 위하여 광강도와 배양액 농도 처리하에 실험을 진행하였다. 엽면적은 광에 의한 차이는 크게 나타나지 않았고 양액의 농도는 EC가 1.0 dSㆍm$^{-1}$처와 1.5 dSㆍm$^{-1}$에서 0.5 dSㆍm$^{-1}$보다 높게 나타났다. 초장은 광강도가 가장 낮은 처리구에서 길었고 약 38%와 60% 차광율 처리사이에는 큰 차이가 없었다. 또한 배양액의 농도에 따라서는 EC가 1.5 dSㆍm$^{-1}$인 처리구에서 EC가 1.0 dSㆍm$^{-1}$과 0.5 dSㆍm$^{-1}$인 처리구보다 초장이 길었다. 엽의 생체중도 처리에 따라 유의적인 차이가 나타났다. 광강도가 가장 낮은 처리구에서 생체중이 가장 높았으나 엽의 건물중은 처리간 차이가 나타나지 않았다. 배양액의 농도처리에 있어서 EC가 1.0 dSㆍm$^{-1}$과 1.5 dSㆍm$^{-1}$인 처리구에서 EC가 0.5 dSㆍm$^{-1}$인 처리구보다 엽의 생체중이 높게 나타났다. 그러나 배양액의 농도는 엽의 건물중에 영향을 주지 않았다. 줄기의 생체중과 건물중은 처리간 차이가 크게 나타나지 않았다. 다량원소의 흡수율을 조사한 결과 주로 배양액의 농도가 증가함에 따라 양분의 흡수율이 증가한다는 것을 알 수 있었다. 또한 광강도의 차이에 따라서 양분의 흡수율이 영향을 받는다는 것을 알 수 있었다. 광강도가 매우 낮은 처리구에서 양액의 흡수는 적었지만 높은 양분흡수율을 보였고 이러한 특성은 각 이온의 종류에 따라 약간의 차이를 보였다.

• The Korean Journal of Ecology
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• v.27 no.4
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• pp.199-210
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• 2004

Effects of nitrogen and phosphorus fertilization on seasonal changes of nutrient content in tree components, and retranslocation N and P in foliage and twig were determined in adjacent 41-year-old plantations of Pinus rigida Miller and Larix kaempferi Gordon on a similar soil in Yangpyeong, Gyeonggi Province. In general, foliage N and P concentrations of L kaempferi were significantly higher than current and 1-year-old foliages of P. rigida. N and P concentrations were higher in foliage than in twigs for both tree species. However, there were no significant differences in foliage and twig N and P concentrations with ages. Significant seasonal differences in foliage and twig N and P concentrations were observed for both tree species because of nutrient retranslocation. Foliage nutrient concentrations were highest in the mid-growing season and lowest in autumn, whereas twig nutrient concnetrations have gradually increased since July. These seasonal trends indicated nutrient retranslocation from foliage into twigs before foliage senescence. However, there were no significant changes in foliage and twig nutrient retranslocation, and no consistent patterns in foliage and twig nutrient retranslocation following N and P fertilizer additions. No significant changes in nutrient retranslocation between different foliage and twig ages were observed following fertilization.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.25-30
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• 1984

Rice seedlings were raised in seedling box for rice transplanter at the temperatures of 32$^{\circ}C$ (day/1$0^{\circ}C$(night) and $25^{\circ}C$/1$0^{\circ}C$ in a phytotron. The endosperm materials were consumed more rapidly at the high temperature (32/1$0^{\circ}C$) than at the low temperature (25/1$0^{\circ}C$) and thus the leaf development was proloted at the high temperature for 15 days from the sowing. But at 35 days after sowing more leaves were developed at the low temperature than the high temperature. The short cotyledon length(5mm) before sowing was more available for the leaf development than the long cotyledon(20mm) because the endosperm materials of the former were consumed slowly. The residual of 10% endsoperm materials, when seedling age was of 2.0 to 2.1, promoted the regrowth of seedlings after machine transplanting.

• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.95-101
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• 2014

Nonpoint pollution sources from agricultural activities are a major cause of water quality impairment. A nutrient management program utilizes farm practices that maintain efficient crop production systems and control agricultural nonpoint pollution sources. The objectives of present study were to identify appropriate best management practices (BMPs) according to changes of cropping system of main upland crop for reducing AGNPs loadings and to simulate the effects of the application of the several BMPs scenarios in Saemangeum watershed. The selected BMP scenarios were: 1) to convert naked barley and hulled barley to hairy vetch or chinese milk vetch, 2) to convert red pepper to soybean crop, and 3) to combine two scenarios, converting naked barley and hulled barley to hairy vetch or chinese milk vetch + converting red pepper to soybean crop. As a result of BMPs application, the crop requirement of nitrogen and phosphorus for upland crop reduced nitrogen by 41% and phosphorus by 47% in scenario 1, whereas scenario 2 reduced nitrogen by 30% and phosphorus by 23%. Overall, scenario 3 reduced nitrogen by 72% and phosphorus by 70% in agricultural non-point pollution sources associated with chemical fertilizer and livestock manure in Saemangeum watershed.

• Korean Journal of Organic Agriculture
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• v.25 no.1
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• pp.161-170
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• 2017

To investigate the influence of long-term organic cultivation on soil characteristics, chemical properties of 35 soils in the national scale organically managed over 10 years were analyzed. 57% of soils which were managed by the materials containing livestock manure have higher nutrient concentration than the materials not containing livestock manure. The decomposed composts (containing livestock manure) had higher amount of $P_2O_5$, CaO, $K_2O$ than organic fertilizers (not containing livestock manure). In the results, the nutrient concentration of soils in long-term organically managed was higher than optimum range of upland soil, especially pH 6.9, available phosphorus (Av. $P_2O_5$) 744 mg/kg, exchangeable calcium $9.4cmol_c/kg$, potassium 2.51 cmolc/kg. On the other hand, more than 50% of soils had lower concentration of exchangeable magnesium than optimum range (soil nutrient distribution was unbalanced). It is suggested that farmers have to be careful to apply organic materials, especially containing livestock manure.