At a time when world population and food supply are in a delicate balance, it is essential that we look at factors to improve this balance. We can alter the environment to better fit the plant's needs, or we can alter the plant to better fit the environment. Improved technology has allowed us to increase the yield level. For moderately detrimental weather events technology has generally decreased the yield variation, yet for major weather disasters the variation has increased. We have raised the upper level, but zero is still the bottom level. As we concentrate the production of particular crops into limited areas where the environment is closest to optimum, we may be increasing the risk of a major weather related disaster. We need to evaluate the degree of variability of different crops, and how weather and technology can interact to affect it. The natural limits of crop production are imposed by important ecological factors. Production is a function of the climate, the soil, and the crop and all activities related to them. In looking at the environment of a crop we must recognize these are individuals, populations and ecosystems. Under intensive agriculture we try to limit the competition to one desired species. The environment is made up of a complex of factors; radiation, moisture, temperature and wind, among others. Plant response to the environment is due to the interaction of all of these factors, yet in attempting to understand them we often examine each factor individually. Variation in crop yields is primarily a function of limiting environmental parameters. Various weather parameters will be discussed, with emphasis placed on how they impact on crop production. Although solar radiation is a driving force in crop production, it often shows little relationship to yield variation. Water may enter into crop production as both a limiting and excessive factor. The effects of moisture deficiency have received much more attention than moisture excess. In many areas of the world, a very significant portion of yield variation is due to variation in the moisture factor. Temperature imposes limits on where crops can be grown, and the type of crop that can be grown in an area. High temperature effects are often combined with deficient moisture effects. Cool temperatures determine the limits in which crops can be grown. Growing degree units, or heat accumulations, have often been used as a means of explaining many temperature effects. Methods for explaining chilling effects are more limited.
Choi Heh Ran;Lim Jeong Hyun;Kim Jung Gon;Choi Kyeong-Gu;Yun Song Joong
KOREAN JOURNAL OF CROP SCIENCE
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v.49
no.6
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pp.522-527
/
2004
Barley growing in paddy fields often suffers from wet-injury due to oxygen deficiency in rhizospere caused by excessive water in the soil. This study was conducted to investigate responsiveness of growth, development and anaerobic glycolysis enzymes to acute hypoxia in barley seedlings. Barley seedlings at the third leaf stage were subjected to hypoxia (1 ppm dissolved oxygen) by sparging the culture solution with nitrogen gas for up to seven days. Length and fresh weights of the shoot and root were affected little by hypoxia for up to 5 days. But root dry weight was slightly decreased by hypoxia for 7 days. In the root, alcohol dehydrogenase and lactate dehydrogenase activities increased drastically under hypoxia, reaching at their maximum levels in 3 to 5 days of hypoxia and decreasing slightly thereafter. However, the activities of both enzymes changed little in the shoot. Increases of their activities in the root were contributed by all the isozymes found in barley. These results suggest that barley seedlings first adapt to hypoxia by rapidly activating fermentative glycolysis to stabilize cellular pH and to increase energy production for the following morphological adaptative changes.
The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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v.4
no.4
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pp.371-382
/
1999
This paper presents the results of recent nutrients measurement and analysis in relation to other environmental parameters such as temperature, salinity, AOU and pH in the South Sea, Korea. In summer, temperature showed stronger correlation with nutrients than salinity and also did the parameters related to biological activities such as pH and AOU. Implications of above results exemplify that primary producers in the vicinity of salt front actively consumed nutrients so that nutrients-salinity correlation is strongly modified in the salt front. Nutrient in winter showed significant correlation only with temperature. Nutrient distribution seems governed by the location of thermal front between vertically mixed cold water in northern area and warm waters flowing north. Due to weak biological activity in winter pH-nutrients correlation, which was strongest in summer ($R^2$ >0.6) dropped sharply in winter ($R^2$ <0.5). Depth integrated nitrate+nitrite, phosphate and silicate values are 321 $mmol{\cdot}m^{-2}$, 23 $mmol{\cdot}m^{-2}$, 637 $mmol{\cdot}m^{-2}$ in summer and 261 $mmol{\cdot}m^{-2}$, 31 $mmol{\cdot}m^{-2}$, 742 $mmol{\cdot}m^{-2}$ in winter, respectively. NIP values in summer exhibit phosphorus deficiency, however, winter situation is reversed for nitrogen. Nitrogen input via precipitation and riverine discharge in wet season seems potentially critical for maintaining the South Sea ecosystem.
Lee, Sang Gyu;Lee, Hee Ju;Kim, Sung Kyeom;Mun, Bo heum;Lee, Jin Hyoung;Lee, Hee Su;Do, Kyung Ran
Journal of Environmental Science International
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v.27
no.4
/
pp.251-259
/
2018
This study was conducted to determine the effects of combination of air temperature and soil water content on the growth, physiological disorder rate, and yield of hot peppers. The study was carried out in a typical plastic house (open on one side and with ventilation fans on the other side), which was maintained with gradient air temperature (maximum difference in air temperature: $6^{\circ}C$). The deficit irrigation (DI) treatment commenced 65 days after transplanting. The height of plant and fresh and dry weights of the stem increased at high air temperature (ambient + $6^{\circ}C$, extreme high temperature; EHT). Furthermore, the leaf area decreased significantly with the DI treatment. There were no significant differences in the stem diameter, number of branches, and fresh and dry weights of the leaves among all the treatments. The net photosynthesis rate of the full irrigation (FI) treatment was higher than that of the DI treatment. The photosynthesis rate at ambient air temperature was $19.7{\mu}mol\;CO_2m^{-2}{\cdot}s^{-1}$, the highest among all the treatments; however, the photosynthesis rate of the EHT treatment decreased by 60% ($12.3{\mu}mol\;CO_2m^{-2}{\cdot}s^{-1}$). Additionally, the formation of guard cells in the leaf was abnormal with the EHT treatment, and there was a decrease in translocation efficiency. The effects of air temperature treatment were more pronounced on the physiological disorder rate and yield. The physiological disorder rate of the EHT treatment was the highest under the DI treatment condition. The yield of the AFI (ambient air temperature with full irrigation) treatment was 3,771 kg/10a, the highest among all the treatments; however, the yield of the EHT treatment with DI and FI was 1,282 and 1,327 kg/10a, respectively. These results indicate that growth and physiological disorder rate improved with the EHT treatment; however, there was a decrease in yield. Furthermore, the formation of guard cells was abnormal and malfunctional.
Types of agricultural policy can be catagorized into two general cases: price and income supports. Income supports are any government program designed to provide farmers with higher incomes than they would receive otherwise. These direct cash payments to farmers are known as "deficiency payment" or "direct payment" because they compensate the farmer for the failure of the market to provide farmers with adequate prices. The direct payment to environment-friendly agriculture is a form of income supports for the agriculture production using less pesticides and chemical fertilizers. Because no significant regulation exists on the use of fertilizers substituting chemical fertilizers for crop, the role of the payment on reducing environmental impacts of agriculture is not entirely clear. This uncertainty is likely to be particularly severe in the case that farmers with low-quality land showing greater demand for fertiliser have an incentive to transition to environment-friendly agriculture. The paper shows the case of the current payment system in Korea.
This study was designed to identify premenstrual syndrome (PMS) and to investigate the correlation between premenstrual syndrome and nutritional intakes. The subjects of this study were 138 college women residing in Busan Metropolitan City. The subjects were asked to complete Menstrual Discomfort Questionnaire (MDQ) regarding PMS, food intake frequencies and nutritional intake. We studied the correlation between PMS symptoms and nutritional intake. The average height and weight of anemic subjects were 161.42 $\pm$ 3.50 cm and 51.87 $\pm$ 5.42 kg. The average BMI (body mass index, kg/$m^2$) was 19.92 $\pm$ 2.14 and PIBW (percent ideal body weight) were 93.02 $\pm$ 9.75%. Except for phosphorous, vitamin A and vitamin C intakes, the intake levels of all other nutrients were below the Korean RDA. The average calorie intake of the subjects was 1645.65 $\pm$ 352.63 kcal (82.2% of the Korean RDA) and iron intake of the subject was 11.06 $\pm$4.03 mg (69.1% of the Korean RDA) . The calcium and vitamin $B_6$ intakes were 512.26 $\pm$ 183.12 mg (73.1% of the Korean RDA) and 1.12 $\pm$ 0.14 mg (80.0% of the Korean RDA), respectively. With regard to their menstrual state, 45.9% subjects responded that their menstrual cycles were irregular. The frequency of PMS of the subjects was 30.2% (over 3 points) on 5 point scale (1 : no. 5 severe). The common symptoms of PMS of the subjects were pain (2.32 $\pm$ 1.01), negative effects (2.27 $\pm$ 0.87), behavioral changes (2.26 $\pm$ 0.85), water retention (2.07 $\pm$ 0.78) , arousal (1.79 $\pm$ 0.84) , autonomic reactions (1.77 $\pm$ 0.87) , lack of control (1.69 $\pm$ 0.75) and decreased concentration (1.68 $\pm$ 0.75) . There was significant correlation between all the PMS symptoms and calcium (p < 0.01) , vitamin E (p < 0.05) , carbohydrate (p < 0.05) . This suggests that PMS represents the clinical manifestation of nutrient deficiency states especially calcium. Therefore we concluded that calcium supplementation is likely to be of benefit in relieving PMS symptoms.
In postmenopausal women, estrogen deficiency can be associated with metabolic diseases, such as obesity, diabetes, and cardiovascular diseases. The purpose of this study was to investigate factors related to lipid, glucose and antioxidnat metabolism. Sprague-Dawley female rats were subjected to either bilateral ovariectomy or sham operation and randomly divided into 3 dietary groups, (n=8) sham-operated fed with normal diet (SHAM), ovariectomized fed with normal diet (OVX), and ovariectomized fed with normal diet supplemented with Eucommia ulmoides extract (OVX-EU). The OVX-EU group showed significantly lower body weight, triacylglycerol, and total cholesterol than that showed by the OVX group. In addition, the OVX-EU group showed improved lipogenesis, glucose-regulating enzyme activities, adipokine and antioxidant enzyme activities. These findings demonstrate that extracts from E. ulmoides extract can be used as a functional food.
Park Myoung Ryoul;Lim Jeong Hyun;Yoo Nam Hee;Kwon In Sook;Kim Jung Gon;Choi Kyung Gu;Yun Song Joong
KOREAN JOURNAL OF CROP SCIENCE
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v.50
no.6
/
pp.400-405
/
2005
Wet-injury often occurs in upland cereals growing in the paddy field due to oxygen deficiency in the rhizosphere caused by excessive water in the soil. Under hypoxia, energy metabolism is diminished causing nonreversible damage to root cells. This study was conducted to investigate effects of hypoxia on root growth and enzymes involved in the fermentative energy metabolism in upland cereals including barley, wheat, rye and triticale. Young seedlings were subject to hypoxia for up to 7 days. Root fresh weight and dry weight were decreased significantly by hypoxia for 5 to 7 days in all cereal seedlings. Root growth retardation under hypoxia was lowest in barley. Hypoxia-induced increases in activity and isozyme expression of alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) were commonly observed in roots of all cereal seedlings. The inherent ADH activity levels were higher in barley but the hypoxia-induced increases in ADH activities were lowest in barley than other cereals. The inherent LDH activity levels were lower in barley and the hypoxia-induced increases in LDH activities were lower in barley than other cereals. The results suggest the importance of the rapid enhancement of fermentative enzyme systems for increased tolerance to hypoxia.
The loss of Residual Heat Removal System (RHRS) event during reduced inventory operation for the Korean Standard Nuclear Power Plants (KSNPPS) is simulated by RELAP5/MOD3 and RELAP5/MOD3.1 Tn cases are considered : Base case for an intact Reactor Coolant System (RCS) with no tent and a vent case for an open system. Comparative simulations of base case are peformed by RELAP5/MOD3 and RELAP5/MOD3. 1 computer codes. The results of too simulations are generally in good qualitative and quantitative agreement. However, since the results of RELAP5/MOD3 simulation reveals the deficiency of RELAP5/MOD3 wall heat model, the RELAP5/AOD3.1 computer code is used for the simulation of the vent case. The analysis result of base case show that two steam generators are insufficient to remove decay heat at one day after shutdown, where the RCS is closed. The RCS pressure increased continuously and reached the RCS temporary boundaries design pressure of 0.24 MPa around 4,000 seconds. In the vent case with a flow capacity equivalent to three times the capacity of Pressurizer Safety Valve (PSV), it is shown that the RCS Pressure does not reach 0.24 MPa and core uncovery does not occur until 10,000 seconds. The detailed discussions on the results of this study suggest the feasibility of RELAP5/AOD3.1 as an analysis tool for the simulation of the loss of RHRS event at reduced inventory operation. The results of this study also provide insight for the determination of proper vent capacity.
Kim, Hea-Tae;Shon, Sang-Jin;Kim, Myoung-Ho;Choi, Mi-Ran;Baek, Wook-Jin
Resources Recycling
/
v.16
no.5
/
pp.19-24
/
2007
Reefs are the marine structure that can give resting, inhabiting, feeding and nursing spaces for a variety of fishes. Usually artificial reefs are made of cement and steels respectively in Japan as well as in Korea. However since resources deficiency has been getting serious, other materials are taken into consideration for the basic bodies of artificial reefs. About 300 thousand tons of waste agricultural plastic films are generated every yew in Korea, but no effective recycling techniques have been developed. In this sense, artificial reefs made of waste agricultural plastic films are the most representative symbol of the recycled products in the Resource Recycling Era. In particular, since these reefs could be made of the semi-cleaned waste agricultural plastic films that still contain high portion of soil, it is very environmentally friendly not only in manufacturing process but also in using under water. Furthermore they have some evident advantages as follows; 1) high fish swarming effect 2) good initial attachment of the marine growths 3) extremely low corrosion to brine 4) easy adjustment of the gravity 5) economical manufacture, transportation and jettison 6) excellent safety to ecosystem caused by lower elution of toxic substances 7) good recyclable property after application and so on.
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