• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.2
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• pp.127-135
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• 1985

The effects of morphological development and environmental temperature on synthesis and accumulation behavior of cell-wall constituents were studied in maize cv. Blizzard and sorghum cv. Sioux and Pioneer 931 at Muenchen Technical University from 1979 to 1981. Various growth stages of maize and sorghum plants were grown on field and phytotron at 4 temperature regimes of 30/25, 25/20, 28/18 and 18/8 degree C and mid-summer sunlight over 13-hour days. The results are summarized as follow: 1. Cell-wall constituents in sorghum and maize plants were shown to have a great synthesis rates at early growth stage from growing point differentiation to final leaf visible. The highest concentration of cell wall contents were found at heading stage with 52-54% and 64-68% of neutral detergence fiber, and 30% and 45% of acid detergence fiber foe maize and sorghum, respectively. 2. The structural carbohydrates, cellulose and hemicellulose, were found as a main components of cell-wall constituents. Cellulose were mainly accumulated in stalks, while hemicellulose were an important cell wall components in leaves and panicle. 3. Synthesis rates of cell-wall constituents and non-strnctural carbohydrates were associated with increasing of temperature. Reserved carbohydrates such as fructosan, mono - and dissaccharose in plant were, however, declined when the temperature exceeded 30 deg C, during the accumulation of cellulose, hemicellulose and lignin were increased continuously. 4. Cell-wall constituents lowered digestibility and net energy accumulation in sorghum and maize plants. In a in vitro and in vivo trial, it was found a negative correlation between digestion dry matter and cell wall constituents, especially cellulose and lignin.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.4
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• pp.339-346
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• 1999

This experiment was carried out to determine harvest date and cultivar effects on the agronomic characteristics, forage yield, and quality of fall sown oat (Avena sativa L.) at the forage experimental field, College of Agriculture and Life Sciences, Seoul National University, Suweon from August to November 1993. The experiment was arranged in a split plot design with three replications. The main plots were consisted of the harvesting dates, suchas early (11 October), mid(21 October), and late(1 November), the subplots were consisted of different maturities of oat cultivars, such as 'West', 'Cayuse' and 'Magnum'. The first heading date of an early maturing culivar, West, was observed on 10 October, and the heading increased up to 30% at the late harvesting date. The average dry matter (DM) content of oat cultivars increased significantly from 12.8 to 15.9% as the growing stage progressed(p<0.01). The average dry matter percentage of West, Cayuse, and Magnum was 15.4, 13.4, and 13.5%, respectively. The crude protein (CP) content of oat cultivars decreased significantly from 20.1 to 13.3% as the harvesting date was delayed(p<0.01), and the CP contents of midseason and late maturing cultivars, Cayuse and Magnum, respectively, were significantly higher than that of an early maturing cultivar West (p<0.01). The mid harvesting date showed the highest acid detergent fiber(ADF) and neutral detergent fiber (NDF) contents than the other harvesting dates, and an early maturing cultivar West had higher ADF and NDF contents than the midseason and late maturing cultivars, Cayuse and Magnum, respectively. The in vitro dry matter digestibility(IVDMD) of oat cultivar West decreased as the harvesting date was delayed, but that of Cayuse and Magnum decreased only by the mid harvesting date. Cayuse and Magnum showed 3~4% higher digestibility than West. The correlation coefficient between IVDMD and ADF content was -0.86. The average dry matter yield of oat cultivars increased from 2,901 to 5,901kg/ha as the harvesting date was delayed(p<0.01), but no significant difference was found among oat cultivars. The corrdelation coefficient between DM yield and gorwing degree days(GDD) was +0.86. The results of this study indicate that a delay in harvesting date would be recommendable for the increase of dry matter yield when fall-sown oat is grown. Especially, the DM yield of the midseason and late maturing cultivars, Cayuse and Magnum, respectively, can be increased without much change of forage quality although the harvesting date are delayed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.729-738
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• 1997

To estimate the change in rice productivity around lake Juam due to construction of artificial lake, growth, yield components and yield of rice were measured at different locations around lake Juam for three years from 1994 to 1996. Automated weather stations(AWS) were installed nearby the experimental paddy fields, and daily maximum, average and minimum temperature, solar radiation, relative humidity, and precipitation were measured for the whole growing period of rice. Plant height, number of tillers, leaf area and shoot dry weight per hill were observed from 8 to 10 times in the interval of 7 days after transplanting. Yield and yield components of rice were observed at the harvest time. Simulation model of rice productivity used in the study was SIMRIW developed by Horie. The observed data of rice at 5 locations in 1994, 3 locations in 1995 and 4 locations in 1996 were inputted in the model to estimate the unknown parameters. Comparisons between observed and predicted values of shoot dry weights, leaf area indices, and rough rice yield were fairly well, so that SIMRIW appeared to predict relatively well the variations in productivity due to variations of climatic factors in the habitat. Climatic elements prior to as well as posterior to dam construction were generated at six locatons around lake Juam for thirty years by the method of Pickering et al. Climatic elements simulated in the study were daily maximum and minimum temperature, and amount of daily solar radiation. The change in rice productivity around lake Juam due to dam construction were estimated by inputting the generated climatic elements into SIMRIW. Average daily maximum temperature after dam construction appeared to be more or less lower than that before dam construction, while average daily minimum temperature became higher after dam construction. Average amount of daily solar radiation became lower with 0.9 MJ $d^{-1}$ after dam construction. As a result of simulation, the average productivity of habitats around lake Juam decreased about 5.6% by the construction of dam.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.126-133
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• 2019

In recent years, the deterioration of fruit quality caused by poor coloration and sunburn disorder has become serious problems in apple market, which is a result of the increase of surface temperature due to the abnormal temperature increase during summer season. This study was conducted to investigate the effect of wind net shading and fine water spray using sprinkler on fruit coloration, sunburn damage and overall fruit quality of 'Fuji' and 'Hongro' apples. Fifteen sprinklers (7L/hr) were installed at the orchard of the Chungcheongnam-do Agricultural Research and Extension Services, located in Sinam-myeon Chungcheongnam-do Korea, at a height of 3m above the apple tree of $1.5m{\times}3.5m$ north-south direction. Fine water spraying treatment was divided into day time spray (10:00 am to 6:00 pm) and all day spray (10:00 am to 10:00 pm) from early July to 10 days before harvest in 2017 and 2018 season, respectively. Temperature of the surface of apple fruit, characteristic of fruit, and degree of sunburn damage were investigated. In 'Fuji', the fruit surface temperature checked at 2 pm on August 10 was decreased considerably in the day time spray ($35.6^{\circ}C$) and wind net ($39.0^{\circ}C$) when compared with the untreated control ($44.4^{\circ}C$). Similarly, the fruit surface temperature also decreased considerably in the all day spray ($35.1^{\circ}C$) and wind net ($36.9^{\circ}C$) treatments when compared with the untreated control ($46.5^{\circ}C$) in 'Hongro' apples. The incidence of sunburn disorder was significantly decreased with day time spray (5.0%), all day spray (5.8%) and wind net (7.0%) when compared with untreated control (23.4%) in 'Fuji' apples. As a results, the treatment of fine water spray and wind net consequently showed 26% and 34% increase of redness ($a^*$) value in the skin color difference, respectively, in 'Fuji' apples.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.3
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• pp.172-179
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• 2022

Sweet potato varieties with high fiber content in the storage root have poor texture when steamed or roasted. This study investigates the difference in fiber content among sweet potato varieties by soil and climate. The average fiber content of 'Hogammi', 'Sodammi', 'Pungwonmi', 'Danjami', and 'Jinyulmi' cultivars from the samples collected at farms in Haenam, Muan, and Unbong, Korea were 95.71, 66.73, 44.55, 40.55, and 38.53 mg/100g FW, respectively. There was no significant difference between site-specific conditions and varieties. Based on the degree of visual fibrousness, 'Hogammi' has an average of 3.6-4.0 with many thick stringy fibers. The fiber content of the 'Hogammi' cultivar was measured across 19 sites representing the main sweet potato growing regions of Korea. The fiber content was between 115.82 and 114.6 mg/100g in Haenam 2 and Boryeong 1, and 87.46 mg/100g in Hamyang. However, the fiber content at the remaining 16 sites was within the range of 94.63-108.52 mg/100g, although there were some site-level differences. The fiber content of the sweet potato storage roots were positively correlated with soil phosphorus (R² = 0.58^**), organic matter (R² = 0.52^*), and pH (R² = 0.51^*), which had a significance of 1% and 5%. The fiber content of sweet potato storage roots was found to have increased with increasing phosphorus content, organic matter and pH in the soil. However, there was no correlation with the amount of precipitation, days of precipitation and hours of sunshine with the fiber content of sweet potato at the selected sites.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.53-59
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• 2014

This study aimed to determine an appropriate cooling timing in the root zone for lowering substrate temperature and its effect on physiological response of sweet pepper (Capsicum annum L. 'Orange glory') grown on coir substrate in summer, from the July 16 to October 15, 2012. Daily temperature of substrate, root activity, leaf water potential, first flowering date, and the number of fruits were measured by circulating cool water through a XL pipe in the root zone during either all day (all-day) or only night time (5 p.m. to 3 a.m.; night) from the July 23 to September 23, 2012. For comparison, no cooling (control) was also applied. Between the $23^{rd}$ of July and $31^{st}$ of August (hot temperature period), daily average temperatures in substrates were $25.6^{\circ}C$, $26.1^{\circ}C$, and $29.1^{\circ}C$ for the all-day and night treatment, and control respectively. About 1.8 to $5^{\circ}C$ lower substrate temperature was observed in both treatments compared to that of control. In sunny day ($600-700 W{\cdot}m^{-2}{\cdot}s^{-1}$), the highest temperature of substrate was measured between 4 p.m. and 5 p.m. under both the all-day and night treatments, whereas it was measured between 7 p.m. and 8 p.m. under the control. Substrate temperatures during the day (6 a.m. to 8 p.m.) and night (8 p.m. to 6 a.m.) differed depending on the treatments. During the day and night, averaged substrate temperature was lower about $3.3^{\circ}C$ and $4.0^{\circ}C$ for the all-day, and $2.1^{\circ}C$ and $3.4^{\circ}C$ for the night treatment, compared to that of control. In the all-day and night treatment, the TD [TD = temperature of (control)] was greater in bottom than that of other regions of the substrate. Between the day and night, no different TD values were observed under the all-day treatment, whereas under the night treatment there was difference with the greatest degree in the bottom of the substrate. During the hot temperature period, total numbers of days when substrate temperature was over $25^{\circ}C$ were 40, 23 and 27 days for the control, all-day, and night treatment, respectively, and the effect of lowering substrate temperature was therefore 42.5% and 32.5% for the all-day and night treatment, respectively, compared to that for the control. Root activity and leaf water potential of plants grown under the all-day treatment were significantly higher than those under the night treatment. The first flowering date in the all-day treatment was similar to that in the night treatment, but 4-5 day faster than in the control. Also, the number of fruits in both treatments was significantly higher than that in the control. However, there was no effect of root zone cooling on eliminating delay in fruiting caused by excessively higher air temperature (> $30^{\circ}C$), although the substrate temperature was reduced $18^{\circ}C$ to $5^{\circ}C$. These results suggest that the method of cooling root zone temperature need to be incorporated into the lowering growing temperature for growth and fruit set of health paprika.

• The Korean Journal of Mycology
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• v.7 no.1
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• pp.13-73
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• 1979

These studies were conducted to investigate nutrient sources and supplementary materials of synthetic compost media for Agaricus bisporus culture. Investigation were carried out to establish the optimum composition for compost of Agaricus bisporus methods of out-door fermentation and peakheating with rice straw as the main substrate of the media. The incidence and flora of harmful organisms in rice straw compost and their control were also studied. 1. When rice straw was used as the main substrate in synthetic compost as a carbon source. yields were remarkably high. Fermentation was more rapid than that of barley straw or wheat straw, and the total nitrogen content was high in rice straw compost. 2. Since the morphological and physico-chemical nature of Japonica and Indica types of rice straw are greatly dissimilar. there were apparent differences in the process of compost fermentation. Fermentation of Indica type straw proceeded more rapidly with a shortening the compost period, reducing the water supply, and required adding of supplementary materials for producing stable physical conditions. 3. Use of barley straw compost resulted in a smaller crop compared with rice straw. but when a 50%, barley straw and 50% rice straw mixture was used, the yield was almost the same as that using only rice straw. 4. There were extremely high positive correlations between yield of Agaricus bisporus and the total nitrogen, organic nitrogen, amino acids, amides and amino sugar nitrogen content of compost. The mycerial growth and fruit body formation were severely inhibited by ammonium nitrogen. 5. When rice straw was used as the main substrate for compost media, urea was the most suitable source of nitrogen. Poor results were obtained with calcium cyanamide and ammonium sulfate. When urea was applied three separate times, nitrogen loss during composting was decreased and the total nitrogen content of compost was increased. 6. The supplementation of organic nutrient activated compost fermentation and increased yield of Agaricus bisporus. The best sources of organic nutrients were: perilla meal, sesame meal, wheat bran and poultry manure, etc. 7. Soybean meal, tobacco powder and glutamic acid fermentation by-products which were industrial wastes, could be substituted for perilla meal, sesame meal and wheat bran as organic nutrient sources for compost media. B. When gypsum and zeolite were added to rice straw. physical deterioration of compost due to excess moisture and caramelization was observed. The Indica type of straw was more remarkable in increase of yield of Agricus bisporus by addition of supplementing materials than Japonica straw. 9. For preparing rice straw compost, the best mixture was prepared by 10% poultry manure, 5% perilla meal, 1. 2 to 1. 5% urea and 1% gypsum. At spring cropping, it was good to add rice bran to accelerate heat generation of the compost heap. 10. There was significantly high positive correlation (r=0.97) between accumulated temperature and the decomposition degree of compost during outdoor composting. The yield was highest at accumulated temperatures between 900 and $1,000^{\circ}C$. 11. Prolonging the composting period brought about an increase in decomposition degree and total nitrogen content, but a decrease in ammonium nitrogen. In the spring the suitable period of composting was 20 to 25 days. and about 15 days in autumn. For those periods, the degree of decomposition was 19 to 24%. 12. Compactness of wet compost at filling caused an increase in the residual ammonium nitrogen. methane and organic acid during peak heating. There was negative correlation between methane content and yield (r=0.76)and the same was true between volatile organic acid and yield (r=0.73). 13. In compost with a moisture content range between 69 to 80% at filling. the higher the moisture content, the lower the yield (r=0.78). This result was attributed to a reduction in the porosity of compost at filling the beds. The optimum porosity for good fermentation was between 41 and 53%. 14. Peak heating of the compost was essential for the prevention of harmful microorganisms and insect pests. and for the removal of excess ammonia. It was necessary to continue fer mentatiion for four days after peak heating. 15. Ten species of fungi which are harmful or competitive to Agaricus bisporus were identified from the rice compost, including Diehliomyces microsporus, Trichoderma sp. and Stysanus stemoites. The frequency of occurrance was notably high with serious damage to Agaricus bisporus. 16. Diehliomyces microsporus could be controlled by temperature adjustment of the growing room and by fumigating the compost and the house with Basamid and Vapam. Trichoderma was prevented by the use of Bavistin and Benomyl. 17. Four species of nematodes and five species of mites occured in compost during out-door composting. These orgnanisms could be controlled through peakheating compost for 6 hours at $60^{\circ}C$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.407-428
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• 1991

The eastern coastal area having variability of climate is located within Taebaek mountain range and the east coast of Korea. It is therefore ease to cause the wind damages in paddy field during rice growing season. The wind damages to rice plant in this area were mainly caused by the Fohn wind (dry and hot wind) blowing over the Taebaek mountain range and the cold humid wind from the coast. The dry wind cause such as the white head, broken leaves, cut-leaves, dried leaves, shattering of grain, glume discolouration and lodging, On the other hand the cold humid wind derived from Ootsuku air mass in summer cause such symptom as the poor rice growth, degeneration of rachis brenches and poor ripening. To minimize the wind damages and utilize as a preparatory data for wind injury of rice in future, several experiments such as the selection of wind resistant variety to wind damage, determination of optimum transplanting date, improvement of fertilizer application methods, improvement of soils and effect of wind break net were carried out for 8 years from 1982 to 1989 in the eastern coastal area. The results obtained are summarized as follows. 1. According to available statisical data from Korean meteorological services (1954-1989) it is apperent that cold humid winds frequently cause damage to rice fields from August 10th to September 10th, it is therefore advisable to plan rice cultivation in such a way that the heading date should not be later than August 10th. 2. During the rice production season, two winds cause severe damage to the rice fields in eastern coastal area of Korea. One is the Fohn winds blowing over the Taebaek mountain range and the other is the cold humid wind form the coast. The frequency of occurrence of each wind was 25%. 3. To avoid damage caused by typhoon winds three different varieties of rice were planted at various areas. 4. In the eastern coastal area of Korea, the optimum ripening temperature for rice was about 22.2$^{\circ}C$ and the optimum heading date wad August 10th. The optimum transplanting time for the earily maturity variety was June 10th., medium maturity variety was May 20th and that of late maturity was May 10th by means of growing days degree (GDD) from transplanting date to heading date. 5.38% of this coastal area is sandy loamy soil while 28% is high humus soil. These soil types are very poor for rice cultivation. In this coastal area, the water table is high, the drainage is poor and the water temperature is low. The low water temperature makes it difficult for urea to dissolve, as a result rice growth was delayed, and the rice plant became sterile. But over application of urea resulted in blast disease in rice plants. It is therefore advise that Ammonium sulphate is used in this area instead of urea. 6. The low temperature of the soil inhibits activities of microorganism for phosphorus utilization so the rice plant could not easily absorb the phosphorus in the soil. Therefore phosphorus should be applied in splits from transplanting to panicle initiation rather than based application. 7. Wind damage was severe in the sandy loamy soil as compared to clay soils. With the application of silicate. compost and soil from mointain area. the sand loamy soil was improved for rice grain colour and ripening. 8. The use of wind break nets created a mocro-climate such as increased air. soil and water temperature as well as the reduction of wind velocity by 30%. This hastened rice growth, reduced white head and glume discolouration. improved rice quality and increased yield. 9. Two meter high wind break net was used around the rice experimental fields and the top of it. The material was polyethylene sheets. The optimum spacing was 0.5Cm x 0.5Cm. and that of setting up the wind break net was before panicle initiation. With this set up, the field was avoided off th cold humid wind and the Fohn. The yield in the treatment was 20% higher than the control. 10. After typhoon, paddy field was irrigated deeply and water was sprayed to reduce white head, glume discolouration, so rice yield was increased because of increasing ripening ratio and 1, 000 grain weight.