• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.84-84
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• 2022

The limit of crop cultivation is moving northward due to the temperature rise by climate change. There is a problem with crop growth if early sowing is performed at a time when the temperature is low. It is difficult to secure crop productivity and cultivation stability due to the low temperature and short cultivation period. Therefore, this study was conducted to analyze the change in growth characteristics and yield of corn for grain when early sowing is performed in central region of South Korea. This experiment was conducted at experimental field of Suwon in 2021. Three varieties of corn for grain such as Kwangpyeongok, Sinhwangok, and Hwangdaok were sown at intervals of 5 days from 20 March to 15 April. The planting density at this time was sown with a row interval of 70 cm and a plant interval of 25 cm. Nitrogen, phosphoric acid, and potassium fertilizers were applied at 17.4 kg, 3.0 kg, and 6.9 kg per 10a, respectively. Phosphoric acid and potassium fertilizers were all applied before sowing and nitrogen fertilizer was applied 50% before sowing and 50% in the fifth leaf period. The corn growth characteristics and yield components were investigated. The seedling establishment rate by sowing date was in the range of 68.5~88.5%, and it showed a difference depending on the variety. The range of days from sowing to tassel and silk emergence by sowing date was 79.9~98.4 and 81.0~98.9 days, respectively. As the sowing date was delayed, the days from sowing to tassel and silk emergence decreased. The growth characteristics and yield of corn by sowing date are as follows. Plant height was the highest at 241.3 cm at the sowing on 25 March, and Stalk diameter was the thickest at 25.6 mm at the sowing on 31 March. The fresh weight per plant was the highest at 728 g at the sowing on 25 March, and the dry weight per plant was the highest at 185 g at the sowing on 31 March. Corn growth characteristics did not show a certain trend depending on the sowing date, and corn growth was more vigorous at the sowing on March 25 and 31 than the others. In the case of ear weight, it was the heaviest with 344 g at the sowing on 25 March, and filled ear length ratio showed a tendency to decrease as the sowing time was delayed. The weight of 100 grains and grain yield per 10a of maize were the highest at 36.0g and 878.7kg/10a, respectively at the sowing on 25 March. Although the growth and yield of corn for grain were good during early sowing in the central region of South Korea, it is necessary to investigate the limit temperature for early sowing of corn by examining the annual variation according to weather conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.2
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• pp.197-211
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• 2015

In order to investigate optimum and marginal sowing date of foxtail millet, proso millet and sorghum in middle area (Anseong, Gyeonggi province) of korea, four levels of sowing date [(May 15(1st), June 6(2th), June 26(3th), July 13(4th)] with mulching and non-mulching were treated in this experiment. We used three crops of foxtail millet, proso millet and sorghum with four varieties of Samdachal, Samdamae, Kyeongkwan1, Hwanggeumjo in foxtail millet, Leebaekchal, Manhongchal, Hwangsilchal, Hwanggeumgijang in proso millet and Nampungchal, Hwanggeumchal, DS202, Moktaksusu in sorghum achieved from RDA. In culm length, sowing date of June 26 was the highest in all varieties of foxtail millet, proso millet and sorghum. Sowing date of May 15 showed the highest ear length in foxtail and proso millet, whereas the highest ear length was obtained from sowing date of June 26 in sorghum. In numbers of leaf, sowing date of May 15 showed the highest in all three crops of foxtail millet, proso millet and sorghum. Days from sowing to heading date were reduced in Samdamae, Kyeongkwan1 and Samdachal as sowing date was late. In Hwanggeumjo it was reduced from the sowing date from May 15 to June 26, but it was same days was taken between June 26 and July 13 sowing date. Days from sowing to heading date of four varieties in proso millet were reduced as sowing date was late. Days from sowing to heading date in sorghum were reduced as sowing date was late, whereas it was increased the $4^{th}$ sowing date of July 13. There were no significant differences in growth and yield characteristics between mulching and non-mulching in four varieties of foxtail millet, proso millet and sorghum with four varieties. The highest grain numbers per panicle, 1000 grain weight and yield per 10a were obtained from sowing date of June 26 in four varieties of foxtail millet, proso millet and sorghum. In sowing date of July 13, all varieties of foxtail millet, proso millet and sorghum were not able to be ripened because of late sowing except Hwnaggeumjo, Manhongchal and Hwanggeumgijang.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.1
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• pp.24-30
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• 2010

Comprehensive studies on seedling production and transplanting cultivation of waxy corn are necessary to fulfill the comsumer's preference for the high quality whole ear waxy corn and its year-round supply for higher price, and to escape marketing in a short period at harvest season. Two waxy corn hybrids (cv. Chalok# 1 and Chalok# 4) were used to study the effects of seeding date, nursery days and plug cell size on growth and yield of waxy corn, and to clarify the reliable transplanting date at the Experimental Field of the National Institute of Crop Science in 2007. The number of days from seeding to silking was increased as nursery days were extended, but the number of days from transplanting to silking was shortened comparing to the direct seeding. Number of days from seeding to silking was shorter by 9~12 days for Chalok# 1 than for Chalok# 4, while the number of days from seeding to silking was shorter by 12~15 days in the second cropping than in the first cropping. Culm length of transplanted waxy corns was decreased as the nursery days were extended. Culm length of seeded Chaok# 1 and Chaok# 4 were decreased by 17% and 24%, respectively, in the second cropping compared to those in the first cropping. Ear length was somewhat decreased as the nursery days were extended. Chalok# 1 in the second cropping the degree of decrease was much higher in second cropping than in first cropping of Chalok# 1. Comparing to the first cropping, number of marketable ears per 10a of Chalok# 1 decreased as high as 64%, while that of seeded Chalok# 4 decreased mere 12% in the second cropping.

• Korean Journal of Environmental Biology
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• v.35 no.3
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• pp.389-397
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• 2017

The purpose of this study was to investigate the characteristics of species by comparing the external shape traits and skull size of Tscherskia triton in Jeju Island from May 2014 to November 2016. Body weight, head-body length, ear length, and hind-foot length were not statistically significant (p>0.05), but tail length was statistically significant in females compared to males (p=0.003). To examine the secondary sexual dimorphism characteristics of the collected T. triton, B_HR, T_HR, E_HR, and H_HR were calculated based on the head-body length, and only T_HR was statistically significant (p=0.003). Because of comparing male and female averages, among the 21 traits, the greatest length of skull (GLS; p=0.020) and occipitonasal length (ONL; p=0.014) were statistically significant and length of incisive foramen (LIF) was statistically significant, when the significance level was 90%. However, the other 18 traits did not show statistically significant differences between males and females (p>0.05). Other than GLS, ONL, interorbital breadth (IB), and breadth of occipital foramen (BOF), there was female-biased SSD. The results of this study are the analysis of external morphology and skull characteristics of T. triton in Jeju Island and will be used as basic data to understand the morphological characteristics of T. triton. In addition, the data can be used as a basic information to compare characteristics of T. triton, which is known as a single species, inhabited in China and Russia. The data will play an important role in biogeography and ecology research of T. triton, based on geographical conditions, climate effects, and habitat environment.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.3
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• pp.156-160
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• 2020

This study was conducted at the National Institute of Animal Science from 2010 to 2017. As a variety that is sufficiently productive in the southern regions to replace imported varieties and sufficiently cold-resistant to be cultivated in the central-northern regions, "IR605" was developed and submitted to the Korea Seed & Variety Service in an application for protection. The novel Italian ryegrass variety "IR605" is a diploid with green leaves, a semi-erect growth habit before wintering, and an erect growth habit in the spring. "IR605" was a medium maturing variety with a heading date of around May 15th. "IR605" had a flag leaf width of 9.9 mm, flag leaf length of 26.7 cm, and plant length on the heading date of 100 cm, which was approximately 5 cm longer than "Kowinearly." The stem thickness and ear length of "IR605" are 0.08 mm thicker and 0.5 cm longer than those of "Kowinearly", respectively. The cold-resistance of "IR605" was weaker than that of "Kowinearly", but strong enough to be cultivated in Pyeongchang, Gangwon province. The dry matter yield of "IR605" (9,308 kg/hectare) was 20% higher than that of "Kowinearly", which was further pronounced in the southern region of Haenam, where there was a 52% increased (p < 0.05). The in vitro dry matter digestibility of "IR605" was 68.4% at which was slightly higher than that of "Kowinearly", The total digestible nutrients was 58.5%, which was slightly lower than "Kowinearly". Overall, the feed quality characteristics of "IR605" were similar to those of "Kowinearly".

• Magazine of the Korean Society of Agricultural Engineers
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• v.8 no.2
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• pp.1193-1199
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• 1966

More stable and higher yields in rice paddy depend mainly upon an adequately balanced supply of water for higher yield. Rice paddy is supplied naturally by rainfall but inevitably requires artificial supplenental irrigation for higher yields. Even though it may be true that the water requirement of rice plants is generally higher than those of other crops, the submerged condition is not necessarily required for rice. The moisture requirements of rice vary according to its growing stages and it is possible to increse the irrigation efficiency by means of lessening the loss due to percolation and evapolation in the field. This experiment was conducted on the effect of the various amount of water supply and different irrigation periods for yield and yield components, and was carried out to find out the most suitable irrigation method and to increase the irrigation efficiency for higher yields in rice paddy. Randomized block design with 3 replications was employed where the 3 levels of the amount of irrigation water; (120% moisture contents), unirrigated (90~100%) and more un irrigated candition (80~90% moisture content), and levels of the various irrigation periods; usual, initial, intermediate and final periods, being treated. The results obtained in this experiment are as follows: 1. As for the physical and chemical and soil properfies, and other characteristics, there are no differences among the treatments enough to be effective for the growth of rice plants. 2. Culm length was measured after harvest as shown in table 2. 3. Difference of the amount of irrigation water did not change the culm length and ear length, however it also indicated more apparent increase in final treatment plots thatn that of usual. 3. No difference in the number of ears and number of ears pers per hill was founded treatments both in the difference of water supply and in the various irrigation periods. 4. There is no difference in the maturing rate and 1000 grains weight. 5. The number of panicles and grains and more increased in 80~100% moisture contents soil than those of 120%. and it shows in un irrigated plots, more irrigated plots and control plots in turn. Other wise according to the period\ulcorner of irrigation the trend is appeared in turn initial, usual, final and intermediate treatments.6. Yield as shown in table 7. 8 was more increased in unirrigated plots(90~IOO% moisture content) than the control plots (120% moisture content) by up to 8.2% and also 3. 2% in more unirrigated plots than that of control by periods is shown: usual plots final, initial, inter mediate treatment plots in turn. 7. The above resutts lead to the conclusion that no remarkable, differences in yields and soil properties are made by the unirrigation. However, it is apparent that this treatment has .some advantages in the points that one could spare the amount of water supply for irrigation with more increase in yield. In addition, a higher temperature and a brisk oxygen supply would be possible throug h this treatments. Accordingly, these treatment would be a more reasonable and economical cultivation method of rice for the better harvest.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.1
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• pp.25-32
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• 2006

This study examined the possibility of using dark-striped field mice as a biological indicator for the environmental radio-surveillance. For this study, dark-striped field mice were caught from five areas of Kyonggi, Kyongsang, Chungchong and Cholla provinces. The external morphological characteristics and isoenzymic types of dark-striped field mice were studied after they were captured. Among the external morphological characteristics, the dark-brown coat, dark back stripe, head-to-tail length, tail length, and ear length matched the taxonomical characteristics of dark-striped field mice. The analyses on L-lactate dehydrogenase, aspartate aminotransferase, and malate dehydrogenese revealed that one species of dark-striped field mice, called Apodemus agrarius, was inhabitated throughout a wide range of Korea. On the other hand, the frequency of micronuclei in peripheral polychromatic erythrocytes to survived mice after irradiation also analyzed. The LD50/30 of A. cgrarius and ICR mice were approximately 5 Gy and 7.9Gy, respectively. The results of the study reveal that wild A. asrarius have a high potential as a biological monitoring system to determine the impact of radiation in areas such as those within the vicinity of nuclear power plants.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.4
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• pp.243-250
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• 2000

Selection of oat variety according to cultivation period is an important to increase productivity of forage crop. To investigate the growth characters and dry matter productivity of oats according to cultivation period, early-maturing oat(EM0) and medium-maturing oat(MM0) variety were sown in spring and autumn at central district of Korea. When oats were cultivated in spring, MMO variety was longer 8 cm in leaf length and wider 5 mm in leaf width than 25 cm and 12 mm of EM0 variety, rexpectively. but in autumn, those were not different between maturities of oat varieties. Plant length of MMO variety was longer 7 cm than that of EM0 Variety in spring cultivation, but in autumn, plant length of EM0 variety was longer 14 cm than that of MMO variety. Heading dates were 20th to 22th May in EM0 variety, and 30th May to 10th June in MMO variety in spring cultivation, and ear of EM0 variety emerged 30th Oct. to loth Nov. but that of MMO variety did not emerge at harvesting day in autumn cultivation. In Spring cultivation, dry matter(DM) yield of EM0 variety was 7,349 kg/ha that was less 56% than 11,466 kg/ha of MMO variety, but In Autumn, was more 15% than 6,575 kg/ha of MMO variety. In conclusion, selection of oat variety in spring and autumn cultivation can be different with cropping system of forage crop, and this trial is suggesting that oat variety could be sown MMO variety in spring and EM0 variety in autumn at central district of Korea. (Key words : Oat variety, Productivity, Cultivation season)

• Korean Journal of Environment and Ecology
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• v.27 no.5
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• pp.550-560
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• 2013

This study was investigated the morphological characters, secondary sexual dimorphism, and habitat patterns of Korean Rattus animals collected on Jeju Island from April 2005 to October 2012. Two wild rat species, namely R. norvegicus and R. tanezumi were identified on Jeju Island based on morphological characteristics and molecular data; however, R. rattus, which had recorded formerly, was not found in this study. Individuals of R. norvegicus were captured from urban, rural, and natural habitats, while those of R. tanezumi were specially found in animal farms and the surrounding areas. Comparing of morphological characters of two species, R. norvegicus had a shorter tail and ears than R. tanezumi (p<0.05), and the ratios of tail length and ear length to those of head-body length showed significantly differences between two species (p<0.05). The body weights (BW) of urban populations of R. norvegicus were significantly heavier than those of rural populations (p<0.05). No secondary sexual dimorphism was found in R. norvegicus, but females of R. tanezumi showed heavier BW than those of males (p<0.05). These findings suggest that it is necessary to revise the records for the existence of R. tanezumi and to confirm the animal fauna and elucidate the distribution and ecological characteristics from further studies using extensive sampling and detailed investigations on Jeju Island and also on the Korean Peninsula.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.1
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• pp.101-108
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• 2014

This study was conducted to investigate the effect of nitrogen rates on the growth characteristics and yield of maize in agricultural fields with the stream. This indicates the necessity and optimal level of nitrous fertilization to examine the possibilities of quantity enhancement. Plant height and ear height of maize were not significantly different among the nitrogen rates. Stem diameter and leaf area index increased in the nitrogen treatment compared to untreated control. Changes of photosynthetic rate in maize leaves depending on nitrogen treatments increased as much as nitrogen rates were increased up to the highest level, 36 kg per 10a. NDF and ADF content levels of maize were investigated with different nitrogen rates regardless of treatments. In the case of NDF, it showed a tendency to decrease after 8 days of tasseling date. ADF had also decreased after 15 days of tasseling date. Nitrogen uptake of maize leaves with different nitrogen rates showed the highest level, $4.9g\;kg^{-1}$ with 36 kg per 10a on the tasseling date. Ear length and 100-kernel weight, there were no significant differences according to yield and the components with different nitrogen rates. Ear diameter and kernel number, nitrogen rates of 18 kg and 36 kg were increased compared to nitrogen rate of 9 kg per 10a and untreated control. The pericarps in 9 kg nitrogen rate and control were thicker than those of 18 kg and 36 kg treatment. The yield, 18 kg, 36 kg, and 9 kg treatments were increased by 10.96%, 9.27%, and 3.31%, compared to control. The component analysis on maize kernel with different nitrogen rates, starch showed no significant differences among treatments. Total sugar in 18 kg nitrogen treatment represented the highest content level, 6.37%. In addition, Amylopectin in 18 kg treatment showed the highest content level of 90.38%. However, amylose in 18 kg treatment showed the lowest level, 9.62% which drew a conclusion that waxy of 18 kg treatment is considered to be the strongest one. From the results described above, nitrous fertilization is essential to grow maize in agricultural fields with the stream. The optimum level of nitrous fertilization is considered 18 kg per 10a.