• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.253-259
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• 2010

This experiment was conducted to evaluate water use efficiency of barley, wheat, and millet as a substitution crop for rice of fallow paddy field. Dry weight (DW), evapotranspiration, and transpiration of crop grown on the lysimeters controlled with 5 levels of groundwater table (GWT), 0, 25, 50, 75, and 100 cm were evaluated for optimum GWT and water use efficiency. All the lysimeters randomized with four replication arrangements were filled up sandy loam and were adjusted to the constant bulk density treated with twice water infiltration from bottom side to upper side of lysimeter. DW of barley, wheat, and millet in the plot of 0cm GWT that is saturated soil showed 34.9%, 44.7%, and 37.1% of that in the plot of 100 cm GWT, respectively showing a serious obstacle in crop growth. Evapotranspiration ratios calculated by evapotranspiration volume (mL) per DW were 166~605 mL for barley, 136~481 mL for wheat, and 81~418 mL for millet showing the order of barley > wheat > millet. Evapotranspiration ratio was increased with decrease of groundwater table that is the condition of moisture saturation. Estimation of GWT for maximum DW of wheat was 76 cm, and those of barley and millet were 100 cm below. The volumetric moisture content of lysimeter soil with cropping was markedly decreased as increase of crop growth because moisture supplying capability by capillary rise of water was less than amount of moisture required by crop.

• Journal of Industrial Convergence
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• v.20 no.11
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• pp.35-39
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• 2022

The purpose of this study was to investigate the effect of sea salt on the growth and moisture content of sweet basil, soil moisture content, and salt stress. As a research method, sweet basil was treated with sea salt at 0, 5, 50, 100, and 200 mM concentration of sea salt was investigated to determine the growth and stress time of sweet basil. As a result of the study, it was confirmed that the leaf width increased by 11% when treated with 5 mM, 49% when treated with 50 mM, and 44% when treated with 100 mM. Leaf length was confirmed to grow by 16% at 5 mM, 59% at 50 mM, and 82% at 100 mM treatment. As a future study, based on the effect of sea salt on the leaf and length growth of sweet basil by concentration, it was considered that more research is needed on the beneficial effects of sea salt on edible, medicinal, and aromatic plants. In addition, although salt has only been studied on stress in crops, we intend to contribute to providing basic data for research on ingredients more beneficial to the environment by finding various edible, medicinal, and aromatic plants using the sun-dried salt used in this study.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.401-411
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• 2015

Drought stress has detrimental effects on the seedling development, vegetative/ reproductive growth, photosynthesis, root proliferation, anthesis, anthesis-silking interval (ASI), pollination and grain yield in maize. Typically, two weeks before silking through pollination are an important time in maize life. Here we reviewed the effects of drought stress on growth, physiological/ molecular researches for drought tolerance, and breeding to genomics in maize. Drought stress during kernel development increases leaf dying and lodging, decreases grain filling period and grain yield. Physiological factors of drought stress/ effects are water content, water deficits, and water potential. Nowdays molecular marker assisted breeding method is becoming increasingly useful in the improvement of new germplasm with drought stress tolerance.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.4
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• pp.232-242
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• 2002

To investigate the effects of arbuscular mycorrhizal (AM) fungus (Glomus intraradices) colonization on drought-stress tolerance, leaf water potential, chlorophyll concentration, P content and carbohydrate composition were examined in perennial ryegrass (Lolium perenne L.) plants exposed to drought-stressed or well-watered conditions. Drought stress significantly decreased leaf water potential, P content and leaf growth. These drought-induced damages were moderated by mycorrhizal colonization. Drought stress decreased the concentration of soluble sugars in shoots. AM plants had a higher foliar soluble sugar than non-AM plants under drought stress condition. Drought stress depressed the accumulation of starch and fructan in shoots, but stimulated in roots. Under drought-stressed condition, starch concentration in roots was higher in non-AM plants than in AM plants. Fructan was the largest pool of carbohydrates, showing the highest initial concentration and the highest net increase for 28 days of treatment. Drought stress slightly decreased fructan concentration in shoots, but remarkably increased in roots. Under drought-stressed condition, fructan concentrations in non-AM and AM shoots at day 28 were 18.7% and 13.3% lower than the corresponding values measured at well-watered plants. However, in the roots, fructan accumulation caused by drought was lessen 13.6% by mycorrhizal colonization. The results obtained suggest that mycorrhizal colonization improves drought tolerance of the host plants by maintaining higher leaf water status and P status, and by retaining more foliar soluble sugars.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.205-214
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• 2020

In this study, we performed to evaluate the water balance during the cultivation of Chinese cabbage and maize according to the soil type and water management method using weighable lysimeters, and to estimate the crop water stress coefficient and minimal water requirement by considering crop productivity and water deficiency. In 2018, Chinese cabbage cultivation period was not irrigated due to frequent rainfall two weeks after planting, so there was no difference in irrigation amount between the non-irrigated and the irrigated and little difference in crop yield. Excluding the Chinese cabbage cultivation in 2018, in the cultivation of Chinese cabbage and maize, the crop yield of irrigated plots was higher than that of non-irrigated plots. The evapotranspiration of irrigated plots was also generally higher than non-irrigated plots. Crop yield and evapotranspiration are closely related, and transpiration is active as biomass increases. The crop water stress coefficients in the middle and the late stage were 0.8 and 0.8 for Chinese cabbage and 0.8 and 0.5 for maize, respectively. The minimal water requirements for Chinese cabbage and maize were 82.0% and 68.8%, respectively, compared to the optimal water requirements (239.4 mm for Chinese cabbage and 466.9 mm for maize). These results can be used as basic data for water management for crop cultivation by securing the minimum amount of irrigation in case of water deficiency.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.2
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• pp.189-195
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• 1997

To cope with increasing importance of water stress in food crop production, characteristics and cultivar differences in physiological responses of winter barley plants to water stress during seedling stage were studied employing three covered-barley, Milyang 12, Durubori, and Olbori, one naked-barley, Baekdong, and one two-row beer-barley, Hyangmaeg. Water stress was given to barley plants by withholding watering in soil-culture pots or by adding P.E.G. (polyethylene glycol, M. W. 4,000) to the nutrient culture solution. When water stress was imposed by withholding watering for 10 days to the seedlings grown in pot-soil for 10 days after emergence, leaf water potential of 5 cultivars was decreased almost to the same degree, from control -3.5 bar to the water stressed -26.6 bar. However, growth and some physiological responses were differently affected by cultivars: The plant height was decreased by 16-26％ : seedling dry weight by 25∼42％ ; chlorophyll content by 21∼39％ ; second leaf survival rate by 8∼18％ ; and free proline content per gram of leaf dry weight was increased from control 0.2∼0.5mg to the water stressed 5.8∼13.2mg. Drought resistances of 5 barley cultivars, based on the leaf survival rate and the decreased rate in seedling dry weight at the end of stress treatment, were high in the order of 3 covered-barley＞naked-barley＞two-row barley.

• Journal of Bio-Environment Control
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• v.11 no.3
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• pp.133-138
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• 2002

This study was conducted to investigate the effece of NaCl concentrations on the growth, photosynthetic rate and mineral uptake of tomato, red pepper, and egg Plant in Pot culture. The growth such as plant height, plant fresh and dry weight, root fresh and dry weight and dried matter rate was decreased as NaCl concentrations were increased. Specially, the growth inhibition of tomato and egg plant was shown at over 40 mM NaCl, and that of red pepper at 20 mM NaCl. Yield of tomato and egg Plant was reduced at over 20 U NaCl, that of red pepper at over 10 mM NaCl. Yield reduction was affected by the number of fruit at low concentration and by mean weight and number of fruit at high concentration. Photosynthetic rate, water potential and stomatal conductance were decreased as NaCl concentrations were increased. The higher the concentration of NaCl, the lower the mineral uptake such as T-N, P, K, Ca and Mg, however, the higher the content of Na and Cl.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.4
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• pp.390-398
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• 2018

Miscanthus is a perennial energy plant that reproduces via rhizomes and has C4 metabolism. The flowering pattern of a wild type M. sacchariflorus (WTM) is affected by environmental conditions such as photoperiod and soil water status. Geodae-Uksae 1 (Geodea), which is a new M. sacchariflorus cultivar, has a lower heading rate than WMS; however the mechanism with why this happens is unknown. To confirm the effects of drought or waterlogging stresses on the growth of WTM and Geodea at the reproductive stage, we investigated variations in morphological characteristics and nutrient contents of the two Miscanthus species after four months of three water treatments. Morphological traits of the two Miscanthus species under the drought condition were similar to those under the control condition. But, the height of Geodea increased by 30% in response to the waterlogging stress. In WTM, the heading rate under the drought condition was lowest, while there was no significant difference between the waterlogging and control conditions. In the two Miscanthus species, nutrient contents, such as sucrose, total N, $P_2O_5$, K and Mg, were the highest under the drought condition, wherea Ca and Mg contents under the waterlogging condition were more than three times lower than those under the drought condition. The current study results showed that drought stress accelerated senescence and then inhibited nutrient mobilization in WTM, while waterlogging stress promoted the growth. This study is the first report to confirm that waterlogging stress promotes flowering of M. sacchariflorus.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.46-46
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• 2023

돌발가뭄 (Flash drought)은 일반적인 가뭄과 달리 기후변화에 따른 기상 이상으로 인해 단기간 급속하게 발생하는 가뭄이다. 짧은 기간에 식생 스트레스가 증가하며, 작물생산량의 감소로 인해 농업 생태계에 피해를 야기하며, 과도한 증발 수요 및 급격한 토양수분의 감소는 수문학적 영향을 미치게 된다. 본 연구에서는 최근 개발된 Flash Drought Intenisty Index (FDII, 2021)를 활용하여 2014년부터 2018년까지 5년간 발생한 돌발가뭄에 분석하였다. FDII는 가뭄 심화속도, 평균 심각도의 두 가지 요소를 곱하여 나타내며, 일반적으로 가뭄 및 비가뭄에 대한 정도를 나타내는 아노말리 (Anomaly) 대신 백분위수 (Percentile)를 활용한다. 국내 돌발가뭄 분석을 위하여 Gravity Recovery and Climate Experiment (GRACE) 위성영상 기반 근역층 토양수분 자료를 활용하였다. 2014년부터 2018년까지 전국 8도 (경기, 강원, 충남, 충북, 전남, 전북, 경남, 경북)를 대상으로 돌발가뭄 사상에 대하여 토양수분 백분위수의 월별 공간분포 및 FDII를 산정하여 국내 돌발가뭄의 강도를 정량화하였다. 지역 및 시기별로 다르게 발생하는 돌발가뭄을 대상으로 FDII를 활용하여 돌발가뭄의 초기 발생, 가뭄 전이 현상 등 시공간적 특성을 분석하고자 한다. 향후 대상 지역의 세분화 및 장기적인 관점에서의 FDII 적용으로 신뢰성 높은 국내 돌발가뭄 모니터링 및 분석 기술로 활용할 수 있을 것으로 기대된다.

• Journal of Biosystems Engineering
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• v.24 no.5
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• pp.439-444
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• 1999

Automated greenhouse production systems often require crop growth monitoring involving accurate quantification of plant physiological properties. Conventional methods are usually burdensome, inaccurate, and harmful to crops. A thermal image analysis system can accomplish rapid and accurate measurements of physiological-property changes of stressed crops. In this research a thermal imaging system was used to measure the leaf-temperature changes of several crops according to water deficit. Thermal images were obtained from lettuce, cucumber, pepper, and chinese cabbage plants. Results showed that there were significant differences in the temperature of stressed plants and non-stressed plants. The temperature differences between these two group of plants were 0.7 to 3$^{\circ}C$ according to species.