• 한국환경농학회지
• /
• 제19권5호
• /
• pp.394-400
• /
• 2000

${\gamma}-Radiation$ at very low doses frequently has a stimulating or hormetic effect on the growth of organism. Effects of low dose ${\gamma}-ray$ irradiation on the root growth of soybean cultivars were investigated and hormetic effects by environmental conditions were compared with the occurrence of increased economic yield, seeds of cultivars were irradiated with the dose of $0.5{\sim}20Gy$ and cultivated in growth chamber controling temperature, humidity, light, greenhouse and field respectively. To understand hormetic effect on root growth of cultivars and the difference of hormetic effect by cultivation environment, harvested root of soybean cultivars were scanned with image file, and root surface area, root length, root average diameter etc. were examined by WinRhizo program. Also, dry weight of cultivars was examined. Root growth and dry weight of soybean cultivars showed apparently hormetic effect at cultivation of growth chamber condition. In field experiment executed for whole life cycle, yields of pea were not different significantly in each ${\gamma}-ray$ irradiated cultivars but weight of one hundred peas increased in whole ${\gamma}-ray$ irradiated cultivars. Increment of yield was assumed to be induced through shortening of maturing stage caused by ${\gamma}-ray$ hormesis in early growth stage.

• 한국작물학회지
• /
• 제49권1호
• /
• pp.7-11
• /
• 2004

Alfalfa (Medicago sativa L.) plants have been reported to be autotoxic as well as allelopathic. Laboratory and greenhouse experiments through petri-dish and pot test were conducted to determine autotoxic effects of alfalfa leaf and soil extracts on the germination or early seedling growth of alfalfa, and to evaluate allelopathic effects of alfalfa leaf residues on alfalfa, barnyard grass, com, eclipta and soybean. Alfalfa seed germination was delayed depending on aqueous extract concentration, with no difference in final germination after 48 hours. Alfalfa root length was more sensitive to the autotoxic chemicals from leaf extracts than was germination or shoot length. Root growth of alfalfa was significantly inhibited at extract concentration of more than 1 g dry tissue/L (g $\textrm{L}^{-1}$). Hypocotyl growth, however, was not affected by all the concentrations of leaf extracts. Soil extracts from 4-yr-old alfalfa stand significantly reduced alfalfa root length by 66%, while soil extracts from 0,1, and 3yr-old stand stimulated root length up to 14-32% over the control. Residue incorporation with dry matters of alfalfa leaf at 100 g $\textrm{kg}^{-1}$ reduced seedling length of several crop and weed species, ranging from 53 to 87% inhibition. Addition of nutrient solution into alfalfa leaf extracts alleviated alfalfa autotoxic effect. This result indicates alfalfa leaf and soil extracts or residues could exert autotoxic as well as allelopathic substances into soil environments during and after establishment.

• 한국유기농업학회지
• /
• 제19권spc호
• /
• pp.222-224
• /
• 2011

The effects of seawater on growth of lettuce(Lactuca sativa L.), leaf perilla(Perilla frutescens var. japonica Hara), red pepper(Capsicum annuum L.) and cucumber(Cucumis sativus L.) seedlings were investigated in the glass greenhouse. These effects were studied on seedlings, and diluted seawater (1%, 5%, 10%, 20%, 50%, 100% v/v) was sprayed enough on leaves. The tested four vegetable crops have well grown up to 10% diluted seawater, but the tested vegetable crops were damaged from increasing salt levels. Of these, lettuce was provided salt-tolerant vegetable crop and red pepper was considered salt-sensitive vegetable crop. The salt tolerance of vegetable crops is different between crops and complicated because of additional detrimental effects caused by accumulated ions or specific ion toxicities in their leaves. These results show that agricultural use of seawater may be benefit crop cultivation in organic farming system as well as in conventional farming system.

• 한국환경교육학회지:환경교육
• /
• 제13권1호
• /
• pp.44-52
• /
• 2000

In this study, the effects of structured controversy strategy, individual learning, and traditional learning on the learning of environmental unit in ‘General Science’ were compared. One hundred and forty-three 10th-graders had been taught about environmental issues-self purification, biological concentration, acid rain, greenhouse effect, noise, and radioactivity-for 6 class hours. Prior to the instructions, environmental attitudes test and self-esteem test were administered. After the instructions, their achievements, critical thinking, environmental attitudes. self-esteem, and views on Science-Technology-Society were examined. The results of 2-way ANCOVA and/or Kruskal-Wallis test revealed that there were no significant main effects in the scores of the achievement test and the critical thinking test. The environmental attitudes test scores tended to be highest in the structured controversy group, and lowest in the traditional learning group. Self-esteem scores of the structured controversy group and the individual learning group were higher than those of the traditional learning group. Significant differences by students' prior achievement level in students' critical thinking, environmental attitudes, and views on Science-Technology-Society were also found.

• Journal of Animal Science and Technology
• /
• 제63권3호
• /
• pp.510-519
• /
• 2021

One of the most pressing issues facing the dairy industry is drought. In areas where annual precipitation is low, irrigation for growing feed presents the greatest water-utilization challenge for dairy producers. Here, we investigated the effects of cultivar and harvest days after planting (DAP) on dry matter (DM) yield and nutritive value of teff (Eragrostis tef), a warm-season annual grass native to Ethiopia that is well adapted to drought conditions. Eighty pots were blocked by location in a greenhouse and randomly assigned to four teff cultivars (Tiffany, Moxie, Corvallis, and Dessie) and to five harvest times (40, 45, 50, 55, or 60 DAP). Cultivars had no effect on DM yield and nutritive value. As harvest time increased from 40 to 60 DAP, DM yield and ash-free neutral detergent fiber (aNDFom) concentrations increased, while crude protein (CP) concentrations and in vitro NDF digestibility decreased. To assess carryover effects of time of harvest on yield and nutritive value, two additional cuttings were taken from each pot. Increasing first-cutting harvest time decreased CP concentrations in the second cutting and reduced DM yields in the second and third cutting. Harvesting teff between 45 and 50 DAP best optimized forage yield and nutritive value in the first and subsequent cuttings.

• 한국가스학회지
• /
• 제20권6호
• /
• pp.102-114
• /
• 2016

파리 기후변화협약에 따라 온실가스 감축의 대안으로 도시가스가 각광받고 있다. 본 논문은 한국과 일본 도시가스산업의 경제적 파급효과를 한국은행의 산업연관표(2013)와 일본 경제산업성의 산업연관표(2011)를 활용하여 비교분석하였다. 분석의 결과, 생산유발효과, 부가가치유발효과, 취업유발효과 등은 모두 한국이 일본보다 크게 나타났다. 그러나 공급지장효과와 물가파급효과 역시 한국이 일본보다 크게 나타나는 것으로 분석되었다. 이에 따라 한국의 도시가스산업을 활성화하기 위해 생산유발, 부가가치유발 및 취업유발효과 등을 확대하고, 공급지장과 물가파급효과 등을 예측하여 국민경제를 안정화할 수 있는 정책이 함께 마련되어야 할 것으로 판단된다.

• 생물환경조절학회지
• /
• 제16권4호
• /
• pp.291-296
• /
• 2007

이 연구는 순환팬에 의해 만들어지는 수평적인 공기흐름이 환경요인들의 수평 및 수직분포에 미치는 영향을 조사하기 위해 수행하였다. 순환팬 가동 유무에 따라 기류 속도, 기온, 상대습도 및 $CO_2$농도의 3차원 분포를 측정하였다. 온실내 기상인자 분포의 균일성은 외기온이 낮아짐에 따라 감소하였다. 무처리시 기온 편차는 4.7, 습도 편차는 19%이었는데 팬을 가동한 경우 그 편차들은 각각 2.2, 6.3%로 감소하였다. 팬 용량이 증가할수록 측점간 기온 편차가 줄어들었는데, 온실 바닥면적당 $0.0104m^3{\cdot}s^{-1}$ 용량의 팬으로 온실내 적정한 공기 유동을 만들 수 있었다. 기온 및 $CO_2$ 농도의 수직분포는 높이나 팬 용량에 관계없이 상당히 균일한 것으로 나타났다. 폭 방향의 기온 편차를 줄일 수 있는 팬 배치와 소용량의 팬을 다수 설치했을 때의 효과에 대한 연구가 더 필요할 것으로 생각된다.

• 한국토양비료학회지
• /
• 제46권6호
• /
• pp.652-658
• /
• 2013

A huge number of greenhouse soils in Korea have accumulated mineral elements which induce many nutritional and pathological problems. The present study was performed to the effects of the reduced fertilization on plant growth, and uptake and partitioning of minerals (N, P, K) and soluble carbohydrates using highly minerals-accumulated farmer's greenhouse soil. On the basis of the recommended application for tomato crop, the application rates of N, P and K were 110(50%)-5.2(5%)-41.5(35%)kg $ha^{-1}$, respectively, using Hoagland's nutrient solution. Tomato growth rates during the whole experiment were not significant between treatments, but it was found that a decrease in daily growth represented after 60 days of treatment (DAT). The reduced application led to a drastic decrease in the concentration of N, P and K in fruits, and, thus, this resulted in lower uptake after 40 DAT. The lower phloem export and utilization of soluble carbohydrates caused an accumulation of extra-carbohydrates in leaves, stems and fruits in the reduced application. The reduced fertilization induced the capture of N, P and K in leaves and of soluble carbohydrates in stems compared to the conventional application. In this study, we suggest that it is possible to delay the first fertigation time in minerals-accumulated soils without an adverse impact on crop growth, but it is necessary to regularly monitor mineral status in soil to ensure a balanced uptake, synthesis and partitioning of minerals and carbohydrates.

• 농업과학연구
• /
• 제44권4호
• /
• pp.604-612
• /
• 2017

In this study, the effects of planting density on the growth of chrysanthemum in a greenhouse were evaluated on two popular varieties (i.e., Sinma and Moonlight). Planting density treatments were as follows: 1) $12cm{\times}12cm$, 2) $6cm{\times}12cm$, 3) $6cm{\times}12cm$ with one-cell vacant, and 4) $6cm{\times}12cm$ with two-cell vacant. Size of each treatments indicate one chrysanthemum was planted in that sized cell that was rectangular shaped field and these treatments were located in a line. Moreover, "one and two-cell vacant" means that it makes middle point of the field empty, offers beside chrysanthemum larger spaces to grow. For the Sinma variety, the results of growth and flowering characteristics at the harvesting stage showed that leaf number, leaf length, flower length, and leaf area were highest when the crop was planted at the $12cm{\times}12cm$ density, and the next preferable density was $6cm{\times}12cm$ with one-cell vacant. For the Moonlight variety, the results showed that stalk height and diameter, leaf number and length, flower length, leaf area, and flower number were highest at the $12cm{\times}12cm$ planting density. For Sinma, ratios of marketable production were 87.5% and 83.3% for the $12cm{\times}12cm$ and $6cm{\times}12cm$ with two-cell vacant, respectively. For Moonlight, ratios were 88.0% and 84.3% for the $12cm{\times}12cm$ and $6cm{\times}12cm$ with two-cell vacant.

• 한국잡초학회지
• /
• 제11권3호
• /
• pp.211-218
• /
• 1991

본(本) 실험(實驗)은 농경지(農耕地)에서 발생(發生)하는 주요(主要) 잡초(雜草)들의 allelopathic effect를 조사하기 위해서 잡초(雜草)들의 수용성(水溶性) 물질(物質)과 건조(乾燥)시킨 잡초(雜草)의 조직(組織)을 여러 농도(濃度)로 처리하여 지표식물(地表植物)의 발아(發芽)의 초기생육(初期生育)을 조사(調査)하였다. 실험(實驗)에 쓰인 여러가지 잡초종중(雜草種中)에 에서 쇠비름과 명아주의 allelopathic effect가 가장 크게 나타났다. 명아주의 증유수(蒸溜水) 추출액(抽出液)은 지표(指標)가되는 식물(植物)의 발아속도(發芽速度)를 대조구(對照區)와 비교할때 감소(減少)시켰으나 쇠비름의 경우는 4.7% 증가(增加)시켰다. 온실(溫室) 실험(實驗)에서 쇠비름은 대맥(大麥), 대두(大豆), 무우, 옥수수 유묘(幼苗)의 출현속도(出現速度)를 대조구(對照區)의 30, 49, 36, 68%로 감소시켰다. 쇠비름과 명아주의 토양내(土壤內) 첨가물(添加物)은 지표식물(地表植物)의 초장(草長)과 건물중(乾物重)을 감소(減少)시켰다.