• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.954-961
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• 2010

Ground-based remote sensing can be used as one of the non-destructive, fast, and real-time diagnostic tools for quantifying yield, biomass, and nitrogen (N) stress during growing season. This study was conducted to assess biomass and nitrogen (N) status of paddy rice (Oryza sativa L.) plants under N stress using passive and active ground-based remote sensors. Nitrogen application rates were 0, 70, 100, and 130 kg N $ha^{-1}$. At each growth stage, reflectance indices measured with active sensor showed higher correlation with DW, N uptake and N concentration than those with the passive sensor. NIR/Red and NIR/Amber indices measured with Crop Circle active sensors generally had a better correlation with dry weight (DW), N uptake and N content than vegetation indices from Crop Circle passive sensor and NDVIs from active sensors. Especially NIR/Red and NIR/amber ratios at the panicle initiation stage were most closely correlated with DW, N content, and N uptake. Rice grain yield, DW, N content and N uptake at harvest were highly positively correlated with canopy reflectance indices measured with active sensors at all sampling dates. N application rate explains about 91~92% of the variability in the SI calculated from NIR/Red or NIR/Amber indices measured with Crop Circle active sensors on 12 July. Therefore, the in-season sufficiency index (SI) by NIR/Red or NIR/Amber index from Crop Circle active sensors can be used for determination of N application rate.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.2
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• pp.53-60
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• 2019

This study was carried out from 2015 to 2016 to identify the suitable sowing and harvesting dates of summer crops in the mountain of Yeongnam, South Korea. The experimental design consisted of the different sowing and harvesting dates as follows: corn hybrid (Z. mays, Kwangpyeongok) of sowing (May 8, 19, and 27) and harvesting (August 10, 20, and 30); sorghum${\times}$sorghum hybrid (Sorghum bicolor ${\times}$ Sorghum bicolor, SS405) of sowing (May 27, June 19 and June 27) and harvesting (August 10, 20, and 30). In corn hybrid, ear rate and dry matter (DM) yield decreased (p<0.05) with the postponement of sowing date. Otherwise, ear rate and DM yield increased (p<0.05) with the postponement of harvesting date. Crude protein content decreased (p<0.05) with the postponement of sowing date, but neutral detergent fiber content increased (p<0.05). In sorghum${\times}$sorghum hybrid, plant length and DM yield with the postponement of harvesting date increased (p<0.05), while crude protein content with the postponement of harvesting date decreased (p<0.05). This study concluded that sowing corn hybrid in early May and sorghum${\times}$sorghum hybrid in early June then harvest in the middle of August was recommend to increase dry matter yield and feed value.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.312-317
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• 2019

This study was conducted with the purpose of examining the suitability of Euphorbia jolkinii Boiss. as cut flower, so that it may be introduced as a new ornamental crop. For this purpose, effect of various holding solutions on vase solution uptake rate, vase life, and relative fresh weight of cut flowering branches of E. jolkinii was examined. After harvest, cut branches were treated with 10, 50, and $100mg{\cdot}L^{-1}$ of 8-hydroxyquinoline sulfate (8-HQS), 0.1 and 0.2 mM of silver thiosulfate (STS), Chrysal, and Floralife. The cut branches of E. jolkinii were placed under the environmental conditions maintained at air temperature of $22.6^{\circ}C$, relative humidity of 45%, and 9/15h photoperiod that was controlled using fluorescent lamps (light intensity of $9.89{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). A holding solution containing $10mg{\cdot}L^{-1}$ 8-HQS was found to be significantly effective for vase solution uptake rate compared to control, $50mg{\cdot}L^{-1}$ 8-HQS, and $100mg{\cdot}L^{-1}$ 8-HQS treatments. However, no significant difference was found in vase life between the branches treated with $10mg{\cdot}L^{-1}$ 8-HQS holding solution and branches of the control group. Increasing holding solution concentrations of STS was found to have negative effect on the vase life of cut E. jolkinii branches. Relative fresh weight of cut E. jolkinii branches were significantly decreased by two commercial holding solutions, Chrysal and Floralife. It is expected that these results would aid further studies on utilization of E. jolkinii as cut flower crop.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.259-270
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• 1985

Meteorological year variations for rice crop from 1973 to 1984 were compared by using air temperature and sunshine hour for nursery period, cooling index for reproductive stage and meteorological yield productivity index for ripening period. The most optimum transplanting date and heading date for crop yield based on real transplanting date-grain yield relationship or heading date-grain yield relationship, meteorological yield productivity index and actual results showed good agreement each other. Around May 26 for transplanting and August 10 for heading were the most optimum date in Indica/Japonica hybrid cultivars while these were about June 8 and August 23 for Japonica cultivars, respectively. On the other hand, theoretical late limiting heading date for safe ripening were August 20 for Indica/Japonica hybrid cultivars and August 30 for Japonica cultivars, respectively, for both methods, cumulative temperature method during ripening with 80% believable frequency and meteorological yield productive index method having 1000(kg/10a) yielding potential. Based on the yield forecast trial, the highest values of photosynthetic efficiency, 2.5%, and crop growth rate, 23g/㎡/day, were recorded during 30 days before rice heading. Considering the photosynthetic efficiency and solar radiation, the potential crop growth rate was more or less 30g/㎡/day and the biological grain yielding potential in a existing cultural practices was approximately 900-1000(kg/10a) in Milyang weather condition. To increase further yielding potential, either photosynthetic efficiency or harvest index or both should be improved by manipulating appropriate canopy architecture, plant spacing, fertilizer, chemical, etc.

• Journal of Korean Society of Forest Science
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• v.112 no.1
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• pp.71-82
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• 2023

Forest biomass is used as a representative indicator of forest size, maturity, and productivity. Therefore, quantitative evaluation is important for management and harvest as well as the evaluation of ecosystem functions and services including CO₂ absorption. The allometric equation is a widely used method for estimating the value of each component through the relative growth rate of plants. Recently, studies indicated that the relative growth of trees is changing because of the increased CO₂ concentration in the atmosphere and the resulting climate change, raising the need to review the previously developed relative growth models and coefficients. In this study, the height-diameter at breast height (DBH) relationships of four major tree species in Korea [(Pinus densiflora (PD), Larix kaempferi (LK), Quercus variabilis (QV), and Quercus mongolica (QM)] were analyzed using the 5th-7th National Forest Inventory (NFI) data. Furthermore, these results were compared with the present yield table from the National Institute for Forest Science. This analysis revealed that the expected height for the same DBH increased as the NFI progressed. For example, in model analysis, the expected heights for PD, LK, QV, and QM for DBH of 25 cm were 12.48, 19.17, 14.47, and 13.19 m, respectively, in the 5th NFI data. In the 7th NFI data, these values were estimated as 13.61 (+9.1%), 21.58 (+12.7%), 15.76 (+8.9%), and 13.93 m (+5.6%), respectively. These results indicate that the major tree species in South Korean forests currently are more vigorous in height growth than in diameter growth when compared to the height-DBH development trends by tree species identified through past survey data.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.1
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• pp.41-46
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• 2022

To investigate the domestic seed production potential of Italian ryegrass, it was sown in autumn in the southern region and harvested in the spring of the following year to investigate the productivity and quality of seeds and straw. Italian ryegrass (Lolium multiflorum Lam.) 'GreenCall' variety was sown in Jinju, Gyeongnam in the fall of 2020 with three seeding rates (20, 30 and 40 kg/ha). The experiment was arranged consisted of a randomized block design with three replications. The ryegrass was sown on October 17, 2020, and the harvest was on May 31, about 60 days from the heading stage. The heading stage of Italian ryegrass was April 28, and there was no difference among treatments. Plant height was significantly shorter in the 40 kg/ha seeding treatment group, and there was no significant difference in the remaining treatments. The resistance of lodging, disease, and cold did not show significant differences among treatments. Spike length and number of seeds per spike were highest at 20 kg/ha seeding amount, and there was no difference in the remaining treatments. The seed yield was the highest at 1,956 kg/ha in the 20 kg/ha seeding rate, and there was no difference in the 30 and 40 kg/ha seeding rates. The dry matter content of seeds and straws was 45.60 and 41.83% on average, and there was no significant difference among treatments. The amount of remaining straw after seed harvesting was found to be 7,689 kg/ha on average on a dry basis, and it was high in the 40 kg/ha sowing area, but there was no significant difference among treatments. According to the above results, it was found that it is most advantageous to sow at 20 kg/ha when producing Italian ryegrass seeds through autumn sowing in the southern region.

• The Korean Journal of Zoology
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• v.13 no.3
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• pp.68-74
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• 1970

In the previous studies, the present author found that high proportion of the follicular oocytes from mouse and rabbit ovaries are able to resume their maturation division in the anterior chamber of the eye in which they have been incubated by auto- or homoplastic transplantation. Especially in the case of the homoplastic transplantation, it was known that no trouble has been detected in the process of resumption of the oval maturation in particular connection with the antigen-antibody reaction between donor and recipient. These findings provide a possibility that the follicular oocytes from various animals would be matured in the eye even after the xenoplastic transplantation. Under such an assumption, the present studies were performed to examine the behavior of the follicular oocytes in the eye chamber of the animals of different species. For the donor of the follicular oocytes, domestic rabbits, albino rats of Sprague-Dowley strain, and albino mice of A-strain bred in our laboratory were used. The oocytes obtained from the ovarian follicules were introduced to the anterior chamber of the eye of different species of animals, with an exception of rabbit in which only the female animals were used as a recipient. The procedures of collection of ova, introduction to the eye, harvest from the eye ball, fixation, and staining were the same as mentioned in the previous reports (Cho, 1967b; Cho and Kim, 1968). The conclusions obtained are summarized as below. 1. The rabbit follicular oocytes are able to mature in the eye chambers of both male mouse and rat, although the proportion of the maturation is lower than when they are incubated autoplastically in the eye. When the ova were incubated in the male mouse eye for 24 hours, 21 per cent of them showed chromosomes at metaphase I and II, whereas the rate was 32 per cent when they were incubated in the eye of the male rat. These are apparently low comparing to the rate of 52 per cent of autoplastic transplantation. 2. When rat follicular oocytes were transferred into the mouse eye chamber and recovered after 24 hours, 43 per cent of them produced the mataphase I and II chromosomes. This proportion was higher than the result of the homoplastic transplantation which yielded 23 per cent of the ova on maturation. 3. The most striking result was found in the experiment with mouse follicular oocytes. Seventy-six per cent of the oocytes resumed their maturation division within 24 hours after they were transferred into the male rat eye chamber, and this figure was significantly high compared to the result o 55 per cent obtained by the homoplastic transplantation. In the rat eye, the induction of the degenerative ova also was low (19%). On the other hand, the proportion of the oval maturation decreased to 45 per cent, while that of degeneration increased 33 per cent when they were incubated in the eye of the female rabbit. 4. It was apparent from the present experiments that the follicular oocytes can reveal their activation to maturation in the eye chamber which contains aqueous humor which is known to be composed of low protein content and of very little gamma-globulin which acts as an antibody(Oser, 1965), and that it shows higher osmolarity than blood serum(Levene, 1958). Taking these properities into consideration the humor may provide unfavourable environment to the cells and tissues incubated in. However, it could be noteworthy finding that only the follicular oocytes in the eye of the different species can grow in healthy condition although the maturation rates are varied with the animal species. The fact that the rabbit follicular oocytes show the lower proportion in maturation may be due to the greater amount of the yolk granules in the egg cytoplasm than those in the mouse and rat oocytes. That the mouse oocytes incubated in the eye of the rat mouse and rat oocytes. That the mouse oocytes incubated in the eye of the rat resumed their maturation process in greater proportion would e explained by the fact that the rat eye chamber particularly provides the better environment to the mouse oocytes than the eye chamber of mouse does.

• Journal of the Korean Society of International Agriculture
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• v.31 no.3
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• pp.249-254
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• 2019

'Japonica 6' is a japonica rice variety developed from a cross between 'MS11', the beginning variety adaptable to tropical region, and 'IR86743-28-1-4', an elite line of high yield and good plant type by a Korea(RDA)-IRRI cooperative breeding program at IRRI in 2017. The growth duration of 'Japonica 6' is 121 days from sowing to harvest. It is 10 days later than that of the check variety 'MS11'. The culm length of 'Japonica 6' is 70 cm, and 1,000-brown rice grain weight is 26.7 g. It has a shorter culm and a larger grain. size than that of MS11. 'Japonica 6' is moderately resistant to blast disease but susceptible to bacterial blight, tungro virus and plant hoppers. The milled rice recovery rate of 'Japonica 6' is improved than that of 'MS11'. The head rice rate of 'Japonica 6' is significantly higher than that of 'MS11'. Yield of 'Japonica 6' is averagely 3.59 MT/ha of milled rice in 5 areas of the Philippines. The 'Japonica 6' was registered in Philippines and would be adaptable to the diverse regions of tropical Asia (Registration No in Philippines. BPI-NSIC-2017-Rc 484SR).

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.483-489
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• 2016

The type approval test for USCG Phase II must be satisfied such that living natural biota occupy more than 75 % of whole biota in a test tank. Thus, we harvested a community of natural organisms using a net at Masan Bay (eutrophic) and Jangmok Bay (mesotrophic) during winter season to meet this guideline. Furthermore, cell viability was measured to determine the mortality rate. Based on the organism concentration volume (1 ton) at Masan and Jangmok Bay, abundance of ${\geq}10$ and $<50{\mu}m$ sized organisms was observed to be $4.7{\times}10^4cells\;mL^{-1}$and $0.8{\times}10^4cells\;mL^{-1}$, and their survival rates were 90.4 % and 88.0 %, respectively. In particular, chain-forming small diatoms such as Skeletonema costatum-like species were abundant at Jangmok Bay, while small flagellate ($<10{\mu}m$) and non chain-forming large dinoflagellates, such as Akashiwo sanguinea and Heterocapsa triquetra, were abundant at Masan Bay. Due to the size-difference of the dominant species, concentration efficiency was higher at Jangmok Bay than at Masan Bay. The mortality rate in samples treated by Ballast Water Treatment System (BWMS) (Day 0) was a little lower for samples from Jangmok Bay than from Masan Bay, with values of 90.4% and 93%, respectively. After 5 days, the mortality rates in control and treatment group were found to be 6.7% and >99%, respectively. Consequently, the phytoplankton concentration method alone did not easily satisfy the type approval standards of USCG Phase II ($>1.0{\times}10^3cells\;mL^{-1}$ in 500-ton tank) during winter season, and alternative options such as mass culture and/or harvesting system using natural phytoplankton communities may be helpful in meeting USCG Phase II biological criteria.

• Korean Journal of Plant Resources
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• v.37 no.2
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• pp.149-160
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• 2024

In Korea, potatoes have served as a side dish, but their role as snacks, such as chips or French fries, has recently gained traction. While there is a high demand for processing potatoes, there remains a dearth of research on the impact of double cropping, particularly during autumn, on processing quality. Therefore, this study was conducted to determine the effects of different spring potato cultivation periods on growth, yield, and processing quality during autumn cultivation. Following spring planting, harvest was carried out four times: 70 days, 80 days, 90 days, and 100 days. Subsequently, autumn cultivation was carried out in Gangneung and Seocheon regions using these seed potatoes. Results showed an increase in above-ground emergence rate with shorter spring growing period. When seed potatoes with a spring cultivation period of 80 and 90 days were grown in the autumn in the Gangneung region, the stem length was 47.2 to 48.9, which was greater than that of other treatments. However, stem number and leaf color (SPAD) showed no significant differences across cultivation periods. The number of tubers, tuber weight, yield, and marketable yield did not vary significantly with cultivation periods but described clear cultivar dependent differences. The tuber weight of the Saebong cultivar in Gangneung and the Eunseon cultivar in Seocheon was superior. The starch content peaked at 7.9% when seed potatoes grown for 80 days in the spring were harvested after autumn cultivation in the Gangneung region, but there was no significant differences in the Seocheon region. Glucose content showed a clear difference depending on the cultivation period, increasing with longer spring cultivation period during autumn cultivation. In conclusion, as a result of the effect of the spring potato cultivation period on the growth, yield, and processing quality of tubers when cultivating potatoes in double-cropping, the differences depending on the cultivation period were insignificant, while cultivar-based disparities were pronounced. The Eunseon cultivar exhibited robust above-ground growth and yield, while the Saebong cultivar demonstrated excellent processing quality.