• 한국토양비료학회지
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• 제49권5호
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• pp.531-540
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• 2016

The adoption of legume cover crops in no-tillage system can contribute to improve soil fertility by providing several benefits, including reduction in soil erosion, suppression of weed growth and N supply to subsequent crops. We conducted a field study to investigate the effect of cover crops and nitrogen fertilization rates on yield and nitrogen use efficiency of waxy corn (Zea mays L.) in no-tillage upland field. Two legume cover crops, hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnuturn L.) were mechanically terminated with roller in early June. For each cover crop treatment, nitrogen (N) fertilizer was applied at three different rates (145, 72.5 and $0kg\;N\;ha^{-1}$). The growth and yield characteristics of corn were significantly affected by the N fertilization rates in crimson clover plots, which suggest N mineralization from the cover crop residue was not sufficient. In contrast, N fertilization rates had no significant effect on growth and yield of corn in hairy vetch plots, indicating that the amount of N released from the cover crop is large enough to meet most of the N requirement of corn. However, the application of N fertilizer in hairy vetch cover plots resulted in slight increase of crop yield, though not statically significant, and high levels of N concentration in corn plant tissue possibly due to luxury consumption of N. Organic residues on the soil surface in hairy vetch cover plots had substantial amounts of N after harvest, ranging from 100 to $116kg\;N\;ha^{-1}$, which is presumably retained during winter season and released by microbial mineralization in subsequent year. The highest nitrogen yield efficiency was achieved in the plot with hairy vetch cover and no N fertilizer application, followed by the plot with hairy vetch cover and $72.5kg\;N\;ha^{-1}$ fertilization rate. In conclusion, hairy vetch showed better performance in corn productivity as compared with crimson clover. In addition, it was concluded that the application of N fertilizer between 0 and $72.5kg\;N\;ha^{-1}$ in combination with hairy vetch cover crop might be most efficient for corn yield under no-tillage system with climatic and soil characteristics similar to those of the experimental site.

• 한국인구학
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• 제8권1호
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• pp.47-65
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• 1985

Three stages of population growth during last forty years affected differently to the labor force and employment in Korea. The first impact of rapid population growth on the labor force occured after the end of World War II. Sudden growth of population due to repartriation and refugees directly increased the labor force. Deteriorating labor market conditions were caused not only by the explosive labor supply but also by the shortage of employment opportunities due to a lack of productive facilities. This severe excess supply of labor continued until the early 196Os. Population growth in the second stage which caused by high fertility during the post Korean War baby boom period induced an eventual increase in the labor supply with time lag of more than fifteen years. Younger persons born during baby boom period were flooded the labor market. Fortunately, job opportunities were expanded more rapidly than the labor force supply because high rates of economic growth and speedy industrialization were continued until the later half of 1970s. Unemployment, therefore, decreased dramatically during this period. The effect of third stage which is characterized as mitigated population growth due to birth control has appeared in the labor market since late 1970s. The growth rate of labor force has been going down and the proportion of younger workers was also been decreasing. From the early 1980s, furthermore, partial disharmony between supply of and demand for the younger workers is closing up. Less educated younger workers who works at low wage are lacking while more educated youngers who want to work at high wage are being excess, because a lot of younger prefer higher education rather than productive job. It is expected that the structural inharmony will be diversified in the future in Korea. The labor force will be changed to middleaged, highly educated and womenized till year 2000, and, after then, to old-aged. On the demand side, industries and jobs will transferred to be labor-saving and soft. These structural changes of labor supply and demand will not matching in time. Aggregate supply of labor force will be steadily increasing more rapidly than aggregate demand for labor until year 2000, and this trend will continue to the first one or two decades of the 2lth century because the persons born dufing the baby boom pariod are being eligible couples in recent. Therefore, conclusion is that appropriate manpower development policy as well as sustained birth control policy is necessary for harmonizing the structural unbalance and the disequilibrium between aggregate labor supply and demand in the future.

• 한국토양비료학회지
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• 제31권4호
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• pp.373-379
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• 1998

토양 유기물과 인산 함량이 보통수준이고 규산함량이 낮은 산성의 식양질 논에서 유연탄회와 무연탄회를 각각 0, 50, 100, $150Mg\;ha^{-1}$ 시용하여 벼를 맥주보리 후작으로 재배한 결과, 석탄회의 토양개량효과가 지속되면서 벼 생육이 향상되었다. 벼 수량성은 무연탄회시용구 보다 유연탄회시용구에서 우수하였으며, 시용량 별로는 유연탄회 100 > 150 > 50 > 무연탄회 50 > 100 > 석탄회 무시용 > 무연탄회 $150Mg\;ha^{-1}$ 시용구 순으로 높았다. 그리고, 쌀 증수효과는 유연탄회시용구의 경우 6.2($50Mg\;ha^{-1}$ 시용구)~14.4%($100Mg\;ha^{-1}$ 시용구), 무연탄회시용구에서는 -0.6($150Mg\;ha^{-1}$ 시용구)~6.6%($50Mg\;ha^{-1}$ 시용구) 이었으며, 최고수량은 각각 $5.084Mg\;ha^{-1}$과 $4.738Mg\;ha^{-1}$이었다. 벼의 수확기 도복율은 유연탄회시용구에서는 20($50Mg\;ha^{-1}$ 시용구)~40%($150Mg\;ha^{-1}$ 시용구) 범위로 시용량이 많을수록 현저히 증가되었으나 무연탄회시용구에서는 1.3($150Mg\;ha^{-1}$ 시용구)~15%($50Mg\;ha^{-1}$ 시용구)로 유연탄회시용구와 반대경향을 보였다. 또한, 벼 증수효과가 우수하였던 유연탄회시용구에서는 수확기 토양의 pH와 유효인산, 치환성 양이온, 유효규산 등이 대조구 보다 양호한 수준을 보이므로써 석탄회시용 3년차에서도 작물의 생육에 대한 잔효가 기대되어졌다.

• 한국물환경학회지
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• 제23권4호
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• pp.518-526
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• 2007

There have been serious soil erosion and water pollution problems caused by highland agriculture practices at Doam-dam watershed. Especially agricultural activities, chemical and organic fertilizer and pesticide applications, soil reconditioning to maintain soil fertility are known as primary causes of soil erosion and water qaulity degradation in the receiving water bodies. Among these, soil reconditioning can accelerate soil erosion rates. To develop soil erosion prevention practices, it is necessary to estimate the soil erosion from the watershed. Thus, the Universal Soil Loss Equation (USLE) model has been developed and utilized to assess soil erosion. However, the USLE model cannot be used at watershed scale because it does not consider sediment delivery ratio (SDR) for watershed application. For this reason, the Sediment Assessment Tool for Effective Erosion Control (SA TEEC) was developed to assess the sediment yield at any point in the watershed. The USLE-based SA TEEC system can estimate the SDR using area-based SDR and slope-based SDR module. In this study, the SATEEC system was used to estimate soil erosion and sediment yield at the Doam-dam watershed using the soil properties from reconditioned agricultural fields. Based on the soil sampling and analysis, the US LE K factor was calculated and used in the SA TEEC system to analyze the possible errors of previous USLE application studies using soil properties from the digital soil map, and compared with that using soil properties obtained in this study. The estimated soil erosion at the Doam-dam watershed without using soil properties obtained in the soil sampling and analysis is 1,791,400 ton/year (123 ton/ha/year), while the soil erosion amount is 2,429,900 ton/year (166.8 ton/ha/year) with the use of soil properties from the soil sampling and analysis. There is 35 % increase in estimated soil erosion and sediment yield with the use of soil properties from soil reconditioned agricultural fields. Since significant amount of soil erosion are known to be occurring from the agricultural fields, the soil erosion and sediment yield from only agricultural fields was assessed. The soil erosion rate is 45.9 ton/ha/year without considering soil properties from soil reconditioned agricultural fields, while 105.3 ton/ha/year after considering soil properties obtained in this study, increased in 129%. This study shows that it is very important to use correct soil properties to assess soil erosion and sediment yield simulation. It is recommended that further studies are needed to develop environment friendly soil reconditioning method should be developed and implemented to decrease the speed of soil erosion rates and water quality degradation.

• 한국가족복지학
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• 제55호
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• pp.129-156
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• 2017

본 연구는 최근 가족에 대한 여성의 가치관 변화 및 경제적인 이유로 인해 의도적으로 자녀를낳지 않는 부부가 늘어나는 상황에서 직장기혼여성 중 특히 무자녀인 여성들을 대상으로 향후이들의 출산계획에 미치는 요인을 규명하고, 이를 토대로 출산율의 회복을 위한 정책적 함의를 제시하는데 그 목적을 두고 있다. 이를 위해 여성가족패널의 1-5차 데이터를 이용하여 현재 직장에 종사하고 있는 가임 가능기(27-49세) 기혼 무자녀 여성(1,020명)을 대상으로 근로조건 및 출산장려제도가 첫 자녀 출산 의사에 미치는 영향을 교차분석 및 로지스틱 회귀분석을통해 분석하였다. 교차분석결과 근로 및 제도적 요인 변수 중 정규직 여부, 산전후휴가 제공여부, 육아휴직 제공여부, 출산장려금 제공여부와 이러한 제도에 대한 직장 여성들의 인식 정도가 첫 자녀 출산의사와 어느 정도 상관관계가 있음을 알 수 있었다. 반면 로지스틱 회귀분석의 결과 현재 진행되고 있는 다양한 정부주도형 출산장려정책들이 아직까지는 여성의 출산의사에 큰 영향을 미칠 정도로 실효성을 담보하지는 않고 있는 것으로 드러났다. 또한 무자녀기혼 직장여성들의 출산장려제도에 대한 높은 인지가 반드시 출산의사의 제고로 이어지지 않는다는 사실도 확인 할 수 있었다. 이러한 연구 결과를 바탕으로 일-가정 양립제도의 보편적확산, 첫 자녀 출산에 대한 지원 확대 및 근로시간의 단축, 출산 후 여성의 직장안정성 보장등을 본 연구의 함의로 제시하였다.

• 한국토양비료학회지
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• 제39권6호
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• pp.403-408
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• 2006

시험에 사용한 팽화왕겨퇴비는 T-N 1.173%, 질소무기화율 33.5%, C/N율 35.4로써 높은 C/N율을 가졌다. 본시험은 전북통의 토양에서 동진 1호를 재배하였으며 2년간 팽화왕겨퇴비를 시용하였다. 팽화왕겨퇴비의 시용은 유기물 및 치환성 칼륨 함량을 증가시켰으며 시용량이 증가할수록 용적밀도 및 공극률이 향상 되는 효과를 나타내었다. 토양 중 $NH_4-N$ 용출양상은 최고분얼기 이전까지는 표준시비구에서 높았다. 시비질소 흡수량은 생육초기 표준시비구에서 많았으나 성숙기에는 팽화왕겨퇴비 시용구에서 다소 많았으며, 팽화왕겨퇴비 시용구들 간을 비교해 볼 때 생육전반에 걸쳐 50% 대체구에서 흡수량이 가장 많았다. 질소 이용률은 팽화왕겨퇴비 시용구에서 전반적으로 높은 이용률을 보였다. 쌀수량은 표준시비에 비해 모든 팽화왕겨퇴비 시용구에서 낮았으나 팽화왕겨퇴비 40% 시용구에서는 표준시비와 거의 비슷한 수준의 수량을 보였다.

• 한국토양비료학회지
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• 제48권4호
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• pp.295-304
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• 2015

To develop a technique for efficient management of fertility for cucumber in greenhouse, a quick test method to quantify nitrate ($NO_3{^-}$) content in soil solution and leaf petiole juice using a simple instrument that are easy to use for farmers was investigated. N fertilizer (urea) was applied at 0, 50, 100 and 200% levels of the recommended application rate from 30 days after transplanting to harvest by soil fertigation treatments. Stable results were obtained from analysis of nitrate ($NO_3{^-}$) using top $10^{th}$ or $11^{th}$ leaf petioles collected between 10 to 11 am in the morning. Under the semiforcing culture, $NO_3{^-}$ content of leaf petiole juice was highest at 60 days after transplanting (DAT) at all fertigation treatments. Appropriate $NO_3{^-}$content of leaf petiole juice was $2,418{\pm}78{\sim}2,668{\pm}118$ at 45 DAT, $3,032{\pm}90{\sim}3,332{\pm}63$ at 60 DAT, $2,709{\pm}50{\sim}3,158{\pm}155$ at 75 DAT, $2,535{\pm}49{\sim}2,907{\pm}83$ at 90 DAT, and $2,242{\pm}48mg\;L^{-1}$ at 105 DAT. In addition, appropriate $NO_3{^-}$ content of soil solution was $167{\pm}9{\sim}212{\pm}15$ at 45 DAT, $83{\pm}10{\sim}112{\pm}12$ at 60 DAT, $49{\pm}3{\sim}92{\pm}6$ at 75 DAT, $71{\pm}9{\sim}103{\pm}9$ at 90 DAT, and $73{\pm}9mg\;L^{-1}$ at 105 DAT. The cucumber yield at 100% N level of fertigation was $7,770kg\;10a^{-1}$ and no difference in yield was found at 200% N level of fertigation. However, there was 12% decrease in yield at 50% N fertigation and, 17% decrease at 0% N fertigation. Under retarding culture, $NO_3{^-}$ concentration of leaf petiole juice was highest at 55 days after transplanting (DAT) at all fertigation treatments. Appropriate $NO_3{^-}$ content of leaf petiole juice was $2,464{\pm}102{\sim}2,651{\pm}33$ at 45 DAT, $3,025{\pm}71{\sim}3,314{\pm}84$ at 55 DAT and $2,488{\pm}92mg\;L^{-1}$ at 65 DAT, respectively. Appropriate $NO_3{^-}$ content of soil solution was $111{\pm}10{\sim}155{\pm}14$ at 45 DAT, $93{\pm}7{\sim}147{\pm}14$ at 55 DAT, $67{\pm}4mg\;L^{-1}$at 65 DAT, respectively. The cucumber yield at 50% N fertigation was not different from $1,697kg\;10a^{-1}$ of 100% N fertigation level and even with that of the 200% N fertigation. However, there was 21% decrease in yield at 0% N fertigation.

• 한국토양비료학회지
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• 제48권1호
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• pp.22-29
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• 2015

The objectives of this study were to monitor the changes in soil solution nutrients and to evaluate their effect on rice uptake and yield. The changes of chemical characteristics of paddy soil solution were examined from the 58th fertilization experiment in which the continuous rice cropping experiment started in 1954 at the National Academy of Agricultural Science. The treatments were no fertilization (No fert.), inorganic fertilization (NPK), inorganic fertilizer plus rice straw compost (NPKC) and inorganic fertilizer plus silicate and lime fertilizer as a soil amendment (NPKCLS). The fertilizers were added at rates of standard fertilizer application rate in which nitrogen (N), phosphate ($P_2O_5$), potassium ($K_2O$), and sililcate ($SiO_2$) were applied at rates of $75{\sim}150kg\;ha^{-1}$, $70{\sim}86kg\;ha^{-1}$, $75{\sim}86kg\;ha^{-1}$, and $7.5Mg\;ha^{-1}$ respectively and lime was applied to neutralize soil acidity until 6.5. Average Electrical Conductivity (EC) of soil solution in NPKCLS and NPKC ranged from 1.16 to $2.00dS\;m^{-1}$. The $NH{_4}^+$ and $K^+$ levels in NPKCLS and NPKC were higher than that of the other treatments, due to high supply power of rice straw compost. The content of $H_3SiO{_4}^-$ was higher in NPKCLS because of silicate application. The dominant ions in soil solution were $Ca^{2+}$, $Mg^{2+}$ and $Na^+$ among cations and $HCO{_3}^-$, $SO{_4}^{2-}$, and $Cl^-$ among anions in all treatments. The continuous application of inorganic fertilizers plus rice straw compost (NPKC) and silicate fertilizer (NPKCLS) led to the changes of various chemical composition in soil solutions. Also, they had a significant impact on the improvement of rice inorganic uptake and grain yield. Especially, inorganic uptake by rice in NPKC and NPKCLS significantly increased than those in NPK plot; 14~46% for T-N, 32~36% for P, 43~57% for K, and 45~77% for Si. Therefore, the combined application of inorganic fertilizers with organic compost as a soil amendment is considered as the best fertilization practice in the continuous rice cropping for the improvement of crop productivity and soil fertility.

• 한국의료윤리학회지
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• 제21권4호
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• pp.301-315
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• 2018

여성은 신체적 특징과 더불어 사회적으로 부과된 '모성'에 의해 임신과 출산, 그리고 양육의 과정에서 책임자로 위임되어 왔다. 특히 임신, 출산과 더불어 낙태 또한 자신의 몸에서 직접 체험하며, 그것으로 인해 삶에 가장 영향을 받는 대상도 여성이다. 그러나 정작 여성은 자신의 몸에 대한 자기결정권을 제대로 갖지 못하고 있다. 이른바 '생명옹호론 대 선택옹호론(pro-life vs. pro-choice)'의 낙태담론 구도 속에서 여성의 자기결정권이란 애초에 '생명존중'에 비해 하위의 것으로 치부되어 왔다. 더욱이 최근 우리사회에서 저출산 위기론이 대두되면서 낙태 처벌이 강화되고 여성의 자율적 결정이나 권리 행사는 더욱 억압되는 상황으로 치닫고 있다. 그런데 일련의 이러한 과정에서 비장애여성과 장애여성 사이에 이중 잣대의 부당함마저 존재한다. 즉 여성들 사이에서 몸의 차등화가 이루어지고 있다. 본 연구는 낙태에서 여성, 특히 장애여성의 자기결정권 문제를 센의 역량 접근 관점에서 고찰한다. 낙태는 개인적이면서도 동시에 사회적인 문제로서 단순히 낙태 허용 여부만이 아니라 임신과 출산, 양육 등과 함께 총체적인 관점에서 조망되어야 하기 때문이다. 결론적으로 낙태에서 장애여성의 자기결정권에 관한 역량 접근은 다음과 같은 윤리적 함의를 기대할 수 있다. 첫째, 장애여성이 처한 다양한 상황적 변수들을 자기결정권 개념 안에 함께 구성하도록 요청한다. 둘째, 장애여성의 실질적 자기결정권의 행사를 위해 개인과 공동체의 연대적 관계를 지향한다. 셋째, 포괄적인 장애여성의 권리로서 '재생산 권리'의 담론으로 확장시킨다.

• 한국동물생명공학회지
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• 제36권2호
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• pp.106-115
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• 2021

Sperm cryopreservation is an important method of assisted reproductive techniques and storing genetic resources. It plays a vital role in genetic improvement, livestock industrial preservation of endangered species, and clinical practice. Consequently, the cryopreservation technique is well organized through various studies, especially on Korean native cattle (Hanwoo). However, the cryopreservation technique of Korean native brindled cattle, which is one of the native cattle species in Korea, is not well organized. Therefore, it is necessary to develop a Supplementary Table technique for the cryopreservation of Korean native brindled cattle. For this purpose, it is important to first evaluate the quality of the currently produced cryopreserved sperm of Korean native brindled cattle. In this study, we randomly selected 72 individual Korean native brindled cattle semen samples collected from 8 different region research centers and used them to evaluate sperm functions. We focused on the quality evaluation of cryopreserved Korean native brindled cattle semen following the measurement of motion kinematics, capacitation status, intracellular ATP level, sperm motility, and cell viability. Then, the values of each of the eight groups were derived from various sperm parameters of nine individual samples, including sperm motility, kinematics, cellular motility, and intracellular ATP levels, which were used to compare and evaluate sperm function. Overall, differences in various sperm parameters were observed between most of the research centers. Particularly, the deviations of motility and motion kinematics were high according to the sample. Therefore, we suggest that it is necessary to develop a standard method for the cryopreservation of Korean native brindled cattle semen. We also suggest the need for sperm quality evaluation of the cryopreserved semen of Korean native brindled cattle before using artificial insemination to attain a high fertility rate.