• Korean Journal of Remote Sensing
• /
• v.37 no.6_1
• /
• pp.1573-1587
• /
• 2021

A Drone image is an ultra-high-resolution image that is several or tens of times higher in spatial resolution than a satellite or aerial image. Therefore, drone image-based remote sensing is different from traditional remote sensing in terms of the level of object to be extracted from the image and the amount of data to be processed. In addition, the optimal scale and size of data used for model training is different depending on the characteristics of the applied deep learning model. However, moststudies do not consider the size of the object to be found in the image, the spatial resolution of the image that reflects the scale, and in many cases, the data specification used in the model is applied as it is before. In this study, the effect ofspatial resolution and image size of drone image on the accuracy and training time of the semantic segmentation deep learning model of six wintering vegetables was quantitatively analyzed through experiments. As a result of the experiment, it was found that the average accuracy of dividing six wintering vegetablesincreases asthe spatial resolution increases, but the increase rate and convergence section are different for each crop, and there is a big difference in accuracy and time depending on the size of the image at the same resolution. In particular, it wasfound that the optimal resolution and image size were different from each crop. The research results can be utilized as data for getting the efficiency of drone images acquisition and production of training data when developing a winter vegetable segmentation model using drone images.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.22 no.2
• /
• pp.112-120
• /
• 1977

In Korea. the cultivating standard of stevia is not established yet. Because stevia is across-fertilizing plant. planting a cutting is its available propagation method. This study was made to know the effective propagation growth and adaptability of stevia in Jeju-do, according to the wintering effect and the planting density.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.38 no.2
• /
• pp.84-90
• /
• 2018

Cultivation of high-quality forage crop by using fallow field during winter is required for national high feed self-sufficiency and establishment of self-supply system of high-quality forage crop. Field experiments for cultivation of high-quality winter forage crop were conducted at the paddy and upland fields in Cheonan and Anseong city with treatments of single Italian ryegrass(IRG) and IRG mixed with forage barley at the paddy field and of single forage barley and forage barley mixed with IRG at the upland field in the Mid-west plain. Several cultivation conditions such as broadcasting IRG seed under standing rice, sowing time, tillage method, drainage condition, mixed sowing with forage barley were compared to know the change of growth, yield and quality of winter forage crop. In particular, over-wintering rate and dry matter yield were decreased significantly in late-sown IRG and moisture-stressed forage barley. Yield and quality of forage crops were increased by sowing after tillage, mixed sowing of IRG with barley at the paddy field with good drainage. High yield as much as dry matter $10MT\;ha^{-1}$ with high feed value could be obtained by early sowing of feed barley mixed with IRG at the upland field. Cultivation conditions such as early sowing, sowing after tillage, drainage management are required for higher dry matter yield, quality and stable cultivation of winter forage crops in the mid-west plain of Korea.

• Korean Journal of Weed Science
• /
• v.16 no.2
• /
• pp.88-99
• /
• 1996

In recent years dry direct-seeding of rice has been encouraged by the government and increasingly practiced by farmers in Korea. This has been bringing up an increased occurrence of weedy rites. Some farmers in the southern region dare to sow the rice before winter after harvest, while most farmers wish to sow as early as possible in the spring to secure the growing period, and to disperse the intensive labor in early May. The purpose of this study was to determine the feasibility of moving the sowing of rice to an earlier date under dry direct-seeding, and to elucidate the nature of emergence of an old strain of rice, weedy rites, and barnyardgrasses tinder this farming practice and their adaptive competence over present cultivate. The presently recommended rice cultivar, Dongjinbyo and an old rice strain, Dadajo which prevailed in early 1900s, almost could not emerge from soil deeper than 6cm and could emerge to only 5.3% at best from 1cm deep loamy soil field when the seeds were sown on Nov. 28. However, two strains of weedy rites being weedy for over 200 years emerged by 17.0 to 63.0% from the loamy and sandy clay loam field 1 to 6cm deep. Emergence of the weedy rites was greater in the loamy soil and at a shallow depth, and negligible from the soil depth of 9cm. Barnyardgrasses sown on Nov. 28 emerged by 13.4 to 51 % from the 1 to 3cm deep loamy soil, and 8.6 to 46.7% from the 1cm deep sandy clay loam. Echinochloa crus-galli var. crus-galli emerged more than var. praticola, and var. oryzicola least. Most of the non-emerged barnyardgrasses seem to have entered secondary dormancy. Seeding rice a month earlier than the season lowered the emergence of Dongjinbyo by ca. 10, 18, and 26%, respectively at 1, 3, and 6cm soil depths, indicating that moving the seeding date a month earlier is impractical. The old strain, Dadajo sown in the soil at a depth of 6cm responded similarly. However, the strain has shown a significantly higher ability in emergence from 9cm deep soil. Weedy rices sown a month earlier A month earlier sown weedy rices have shown very similar emergence rates at various soil depths to those sown on May 1. Barnyardgrasses have also shown similar emergence rates when sown between April 3 and May 1. Like barnyardgrasses, the old strain and weedy rices apparantly posessed a greater adaptability to emerge under lower temperatures, and from deeper soil ; Dongjinbyo${\leq}$ Echinochloa species in that order. However, emergence- speed under lower temperature(sown on April 3) was faster in the order of weedy rice

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.27 no.3
• /
• pp.151-154
• /
• 2007

This experiment was conducted to compare the agronomic characteristics and productivity of introduced crimson clover cultivars at paddy field of Naju(Jeollanam-Do Agricultural Research and Extension) from 2004 to 2006. The crimson clover cultivars used in this study were 4 varieties('Oregon com.' 'Tibbee', 'Contea', 'Linkarus') The fastest flowering variety was chinese milk vetch, while 'Linkarus' was the latest one as of as 5th May. The average dry matter(DM) content was 24.3% and crude protein(CP) content was 14.9%. 'Oregon com.' showed the highest CP content of 18.3% among crimson clover and Chinese milk vetch showed the highest CP content by 19.3%. Average acid detergent fiber(ADF), neutral detergent fiber(NDF) and total digestible nutrient(TDN) content were 35.1%, 45.3% and 58.9%, respectively. With by the winter hardness the productivity of crimson clover cultivars were severely various. Linkarus showed the highest DM yield with 6,986kg/ha but the DM yield of 'Tibbee' and 'Oregon com.' was low by 3,639 kg/ha and 1,980kg/ha, respectively. The results of this experiments indicated that the productivity of crimson clover cultivar varied from winter hardness, therefore we will consider the winter hardness as major factor when introducing crimson clover cultivars into Korea. According to the results obtained from this study, it is suggested that 'Linkarus' would be recommendable for fall sown crimson clover for dry matter production.

• Korean Journal of Weed Science
• /
• v.2 no.2
• /
• pp.152-159
• /
• 1982

To investigate the effect of isoproturon (N,N-dimethyl-N-4-isopropyl phenyl urea) on weed-killing, crop injury and yield of barley, several experiments were conducted by application time, dosage, cultivars and soil texture. For the effective control of weeds the optimum application time was foliage application after winter. Alopecurus aequalis SOBOL was effectively controlled when isoproturon should be applied at three to four leaf-stage and most annual broad-leave weeds emerged through winter and spring could be controlled when applied even at five to six leaf-stage. But among the broad-leave weeds Vicia amoena Fisch. was resistant to isoproturn. The optimum application rate of isoproturon was 240g-300g/10a (prod.). Among 11 cultivars of barley and wheat, phytotoxicity of Olmil, Jokwang and Rye was slighter than that of the other cultivars when isoproturon was treated by foliage application after winter. At the time of foliage application after winter, the variation of phytotoxicity and effectiveness was a little despite the difference of soil texture and the grain yield of barley was higher in the plots treated 240-300g/10a than in other treated plots.

• Korean journal of applied entomology
• /
• v.32 no.3
• /
• pp.338-347
• /
• 1993

The study was to investigate the bionomics, host plants, and oviposition preference of Hishimonus sellatus Uhler. It has 5 generations under natural conditions and the peak of the 3rd generation was observed about mid and late August. Its average developmental durations were 80 days in spring, 69 days in summer, and 77.8 days in autumn. The lengths of each stage were 0.8mm in eggs, 0.9mm in 1st instar, 1.4mm in 2nd instar, 2.1mm in 3rd instar, 2.5mm in 4th instar, 3.2mm in 5th instar, 4.1mm in female, and 3.8mm in male. Hishimonus sellatus overwintered as egg in Morus alba, Humulus japonicus, and Zizyphus jujuba begining mid October, and attacked the shoot of M. alba and H. japonicus about mid and late May, migrated to the Zizyphus jujuba from late June to early July. Female oviposites 32~62 eggs into epidermis of shoot, vagina and vein during their life. The preferred host plants of H. sellatus were Humulus japonicus, Morus alba, Zizyphus jujuba, and ligustrum obtusifolium. Highly preferable oviposition site was H. japonicus, M. albal, Z. jujuba, and L. obtusifolium, etc. On audlt longevity, the host plants as H. japonicus, M. alba, and Z. jujuba were 43$\pm$2 days and A. brevipedenculata, C. mimosoides, L. obtusifolium, V. rosa, A. sinicus and, A. graveolens were more than 25 days, and other host plants were less than 20 days.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.4 no.1
• /
• pp.38-48
• /
• 2002

This study examines the relationships between atmospheric influences and grain yields including yield components as well as growth stages. Data used in this study were collected from the long-term field experiment at Suwon for the period between 1974 and 2000. Mean grain yield of barley cultivar, Olbori, for the recent 14 years(1987∼2000) with warm winters was higher by 0.42 ton per hectare than that for 27 years(1974∼2000) at Suwon as a result of the higher numbers of spikes per unit land area and grains per spike. However, the 1000-grain weight decreased by about 0.6 gram. Mean first day of regrowth for the recent 14 years was earlier by five days than that for 27 years. Also, beginning date of regrowth was positively correlated with that of heading and ripening. Mean period of ripening for the years of 1987 through 2000 was similar to that for 27 years, but mean period of overwintering was shorter by nine days than that for 27 years. On the other hand, mean periods of seedling and tillering were longer by three days than those for 27 years. Meteorological elements at various growth stages affecting grain yield of winter barley were air temperature (positive correlation) and sunshine hour (negative correlation) of overwintering stage, precipitation (negative correlation) of tillering stage, and potential evapotranpiration (positive correlation) of tillering stage. The 1000-grain weight was not significantly correlated with the meteorological elements. Culm length was negatively influenced by high temperature and dry weather situations during the ripening period, but spike length was positively influenced. Overall, it was found that grain yield of barley, cultivar Olbori, was iufluenced by meteorological elements of overwintering, tillering, and ripening stages.

• Horticultural Science & Technology
• /
• v.35 no.1
• /
• pp.38-45
• /
• 2017

We investigated the effects of rising temperatures on the photosynthesis, mineral composition, and growth of radish (Raphanus sativus var. hortensis) in a winter cropping system using a temperature gradient tunnel to predict the impact of rising global temperatures. Vegetative growth, including shoot and root fresh and dry weights, shoot length, and root length and diameter, was high under elevated temperatures (ambient $+4^{\circ}C$ and $+7^{\circ}C$) compared with ambient temperature. At elevated temperatures, the N, P, Ca, Mg, and Fe contents were high in shoots, whereas in roots, the K, Ca, Mg, and Fe contents were high and the Cu content was low. The maximum photosynthetic rates ($22.1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at ambient temperature $+4^{\circ}C$ and $22.9{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at ambient temperature $+7^{\circ}C$) at elevated temperatures were more than twice that ($9.7{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) at ambient temperature, whereas the water use efficiency was lower at elevated temperatures. These results suggest that rising global temperatures will lead to increased mineral absorption and photosynthesis in radish in winter cropping systems, subsequently favoring plant growth, although the water requirements will be high.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.37 no.5
• /
• pp.90-97
• /
• 2009

Sedum takesimenses among the Korean Native Genus Sedum was selected as evergreen ground covers during winter in the central districts of Korea. In order to obtain basic information for production as a pot flower with good quality, the effects of pinching frequencies on growth and flowering of S. takesimense were investigated. S. takesimense plant height became much shorter and numbers of lateral shoots were increased with increased pinching. Shoots of S. takesimense treated with 30% pinching during 2004 and 2005 showed greater length and less number of lateral shoots than those with 60% pinching. Leaves of S. takesimense treated with 70% shading showed a dark green color and had a longer shoot length and a lower number of shoots than cultivation under full sunlight. Therefore, Korean native S. takesimense will be utilized as ground cover treated with 70% shading or under a tree. Therefore, S. takesimense will be promising as ground cover materials in the central districts of Korea.