• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.166-170
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• 2012

This research was carried out to choose the suitable seedling type to transplanting in order to stabilize rice yield. The brief of this research to transplant the seedling divided into 10-day seedling, 20-day seedling, 30-day seedling, 33-day pot seedling in the field of Saemangeum Gyehwa, newly reclaimed land were following; Average salt content in 2 years was reduced from 0.16% to 0.04% after transplanting. Heading date of seedling type was Aug. 14 at 33-day pot seedling compared to 2 days at 30-day seedling, 3 days at 20-day seedling, 5 days late at 10-day seedling. Lodging index was highest at 30-day seedling, and also, field lodging was 50%. Ripening ratio and 1,000 grain weight were similar and panicle number was higher 20-day seedling > 10-day seedling > 33-day pot seedling > 30-day seedling. Rice yield was higher 10-day seedling = 20-day seedling > 33-day pot seedling > 30-day seedling. Head rice ratio was higher in 20-day seedling > 30-day seedling = 10-day seedling > 33-day pot seedling. Amylose content and protein content was not significantly different between seedling types. With this results, the suitable seedling types in newly reclaimed land are 10-day and 20-day seedling.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.39-45
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• 1995

This experiment was carried out at Yeongnam Crop Experiment Station since 1992 to obtain basic information on ecology of weeds and weedy rice in direct-seeded rice fields. Annual grass weeds of Echinochloa sp., Leptochloa sp., Digitaria sp. and Setaria sp.(C4 plant) and weedy rice(C3 plant) were important species in direct seeded rice compared to transplanted rice field. Period of seedling emergence of barnyard grass was varied from 8 days to 20 days depending on seeding date while it was shorter 4 to 6 days than rice. Weed occurrence and the degree of yield loss were varied by cultivation method. In direct seeding method weeds increased 2 to 3 times compared to manual transplanting. The greatest yield loss was recorded in direct seeding(40 to 100%) followed by mechanical transplanting(25 to 35%) and hand transplanting(10 to 20%), in order. Double cropping of rice-barley was reduced weeds about 30% than rice single crop due to alleopathic effect of barley residue or stubble. Weedy rice(red rice) occurrence was closely related with seeding date and tillage methods. Early seeding and reduced tillage enhanced the growth of weedy rice.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.385-391
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• 2012

This study was conducted to investigate the effects of the runner cutting time on the growth and yield of strawberry (Fragaria ${\times}$ ananassa cv. Maehyang and Seolhyang) during nursery period of two consecutive years (2009 and 2010). Strawberry runners which connected from mother plants to daughter plants were cut 30, 20, 10 and 5 days before transplanting day (11 Sep. 2009 and 10 Sep. 2010). When runner cutting time delayed, more nutrition was supplied to the daughter plant until late nursery period. It showed that there was a tendency to increase the fresh weight, crown diameter and leaf chlorophyll content. On the other hand, when the runner was cut earlier, the growth of underground part such as root weight was improved. Irrigation demand increased to 29.7% in case of runner cutting from mother plant compared with runner non-cutting treatment. In addition, infection ratio of anthracnose through runner part was 37.6% higher in case of runner cutting than that of runner non-cutting treatment. After transplanting, budding and flowering period were delayed up to 2 or 3 days because of late runner cutting. But there was no significant difference in marketable fruit yield among runner cutting times. It is recommended to conduct runner cutting 5 or 10 days before transplanting for reducing the occurrence of anthracnose.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.4
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• pp.382-387
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• 2008

This study was conducted to determine the effect of rice bran on rice yield, grain quality and weeds control depending on applying times. The redox potential was severely reduced $4{\sim}7$ days after rice bran application but that of conventional practice was reduced 17 days after transplanting. During the decomposing of the rice bran in the water, the dissolved oxygen in the water was exhausted right away after rice bran application. The dry weight of weed increased as the rice bran application time was delayed that weed dry weights increased by 138% in applying before puddling (ABP), 219% in 5 DAT (days after transplanting), 300% in 7 DAT and 619% in 9 DAT compared to conventional practice. The rice yield reduced remarkably in rice bran treatments after transplanting compared to conventional practice and applying before puddling. In the rice quality, the head rice ratio in the rice bran treatment was higher than that in conventional practice, and its protein content decreased. The results confirm that the rice bran application make the rice palatability higher, but there was no difference in rice qualities depending on application times.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.85-91
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• 2001

To find diagnosing method of nitrogen status in tomato plant for determining optimum application rate of side dress, chlorophyll reading values were measured by portable chlorophyll meter(SPAD 502, Minolta), and compared with nitrogen supplying capability of soils. Regression between dry weight, amount of nitrogen uptake, and chlorophyll reading at stalk positions of tomato grown on the condition of no fertilization were evaluated For 6 green house soils with different nitrate concentrations ranged from $55mg\;kg^{-1}$ to $306mg\;kg^{-1}$. The chlorophyll reading of tomato leave was significantly correlated with amount of nitrogen per unit area of leave suggesting that chlorophyll content is useful for nitrogen diagnosis of tomato plant. The chlorophyll reading showed peak at the 15th leaf of stalk position on the 45th days after transplanting and this suggested that below or near the 15th leaf and before or near the 45th days after transplanting is the critical stalk position and time for diagnosing nitrogen status of tomato by chlorophyll test. The chlorophyll reading at the 14th leaf on the 40th days after transplanting was significantly correlated with soil nitrate status, dry weight and amount of nitrogen uptake by tomato grown with no fertilization. From the above correlation, the chlorophyll reading value of 57.1 at the 14th leaf of tomato was estimated as the critical level for maximum dry weight and amount of nitrogen uptake by tomato grown with no fertilization. Consequently, chlorophyll reading of tomato leaves measured by portable chlorophyll meter was thought to be available as a rapid plant test for predicting the nitrogen supplying capability of green house soils.

• Plant Resources
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• v.4 no.1
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• pp.6-12
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• 2001

Growth and yield of licorice were investigated under the different conditions of ridge height, planting density, and irrigation in order to establish its cultural practices for the domestic production with the aim to substitute the import. Seedlings were grown under low ridge(20cm) and high ridge(40cm) in low density plot(60$\times$30cm) and high density plot(40$\times$30cm), respectively. The low ridge cultivation of large seedlings increased plant height and root length under low density, and stem and root diameter under high density compared to the high ridge cultivation. In the high ridge cultivation, high density plot was 1.1 to 1.3 times in plant height, root length, stem and root diameter as high as low density one. Fresh and dry weight of plant and root in high ridge were 1.3 to 1.5 times as high as those in low one. The growth of small seedlings(4~10g) were generally poor compared to that of large seedlings. High density plot in low ridge showed the good growth characteristics including plant height, root length, stem and root diameter, and number of branch. High density plot was 1.4 to 1.6 times in fresh and dry weight of plant and root as high as low density plot. In the seasonal changes of growth under various irrigation regimes, the twice irrigation a day produced the more number of leaf than the other regimes since around 46 days after transplanting. The former irrigation resulted in 1.2 to 1.4 times in plant height as long as the other irrigations around 26 days after transplanting and then the difference was increased to 1.6 to 2.0 times around 64 days after transplanting. Under the twice irrigation a day, plant height, root length, stem diameter, root diameter, number of leaf, fresh plant weight, dry plant weight, fresh root weight, dry root weight were 1.6 to 2.0, 1.1, 1.2 to 1.6, 1.3 to 1.8, 1.9 to 2.7, 1.7 to 8.0, 1.6 to 2.8,2.0 to 3.0, 1.6 to 2.7 times as high as those under the other irrigation regimes, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.4
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• pp.295-304
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• 2015

To develop a technique for efficient management of fertility for cucumber in greenhouse, a quick test method to quantify nitrate ($NO_3{^-}$) content in soil solution and leaf petiole juice using a simple instrument that are easy to use for farmers was investigated. N fertilizer (urea) was applied at 0, 50, 100 and 200% levels of the recommended application rate from 30 days after transplanting to harvest by soil fertigation treatments. Stable results were obtained from analysis of nitrate ($NO_3{^-}$) using top $10^{th}$ or $11^{th}$ leaf petioles collected between 10 to 11 am in the morning. Under the semiforcing culture, $NO_3{^-}$ content of leaf petiole juice was highest at 60 days after transplanting (DAT) at all fertigation treatments. Appropriate $NO_3{^-}$content of leaf petiole juice was $2,418{\pm}78{\sim}2,668{\pm}118$ at 45 DAT, $3,032{\pm}90{\sim}3,332{\pm}63$ at 60 DAT, $2,709{\pm}50{\sim}3,158{\pm}155$ at 75 DAT, $2,535{\pm}49{\sim}2,907{\pm}83$ at 90 DAT, and $2,242{\pm}48mg\;L^{-1}$ at 105 DAT. In addition, appropriate $NO_3{^-}$ content of soil solution was $167{\pm}9{\sim}212{\pm}15$ at 45 DAT, $83{\pm}10{\sim}112{\pm}12$ at 60 DAT, $49{\pm}3{\sim}92{\pm}6$ at 75 DAT, $71{\pm}9{\sim}103{\pm}9$ at 90 DAT, and $73{\pm}9mg\;L^{-1}$ at 105 DAT. The cucumber yield at 100% N level of fertigation was $7,770kg\;10a^{-1}$ and no difference in yield was found at 200% N level of fertigation. However, there was 12% decrease in yield at 50% N fertigation and, 17% decrease at 0% N fertigation. Under retarding culture, $NO_3{^-}$ concentration of leaf petiole juice was highest at 55 days after transplanting (DAT) at all fertigation treatments. Appropriate $NO_3{^-}$ content of leaf petiole juice was $2,464{\pm}102{\sim}2,651{\pm}33$ at 45 DAT, $3,025{\pm}71{\sim}3,314{\pm}84$ at 55 DAT and $2,488{\pm}92mg\;L^{-1}$ at 65 DAT, respectively. Appropriate $NO_3{^-}$ content of soil solution was $111{\pm}10{\sim}155{\pm}14$ at 45 DAT, $93{\pm}7{\sim}147{\pm}14$ at 55 DAT, $67{\pm}4mg\;L^{-1}$at 65 DAT, respectively. The cucumber yield at 50% N fertigation was not different from $1,697kg\;10a^{-1}$ of 100% N fertigation level and even with that of the 200% N fertigation. However, there was 21% decrease in yield at 0% N fertigation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.52-52
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• 2022

Recently, PE (polyethylene) film has been used increasingly in com cultivation. However, PE films often cause soil and environment contamination. In order to reduce this problem, many researches have been carrying out studies on biodegradable films (BF) that are easily decomposed by soil microorganisms. Therefore, this study was conducted to determine which BF is optimal for growth and yield of com crops while also having the highest rates of film decomposition. BFs Farmsbio (Farm Hannong), Heulgro Film (Sejin Bio), Vonto Film (Eco-Hansung) as well as a selected PE film were used in this study. For the control, we used crops grown without any kind of mulching. Experimental fields were fertilized according to conventional cultivation methods, tilled, and then covered by either BF or PE. After 1 week, com (cv. MIBECK2ho) at the 3-leaf stage (16 days after seeding) was transplanted. Plant height was measured at 18 and 32 days after transplanting and heading stages. Yield components and yield were also measured at harvest. In addition, pH, EC, and decomposition and light transmittance levels of films were investigated during the experimental period. Daily average temperature, relative humidity and organic matter in soils were also measured during the experimental period. There was no significant difference in plant height, heading date, and silking between crops with BFs and PE, but the crops grown with BFs and PE films reached higher growth parameters in a shorter amount of time than the crops in the non-mulching control. Additionally, there were no significant differences in yield components such as length of ears, ear width, ear weight, and yield in crops that were grown using films or crops in the control plot. Light transmittance and decomposition levels of films generally increased with time after transplanting, and was highest in the Heulgro film than other BFs. Soil pH and organic matter in crops using BFs and PE films were significantly higher than in the control plot at 99 and 113 days after transplanting. In general, the EC contents in the control plot was lower than in crops using BFs and PE films. The average daily moisture in soil was higher when BFs and PE films were used than in the control plot. However, the daily average soil temperature was higher in crops using BFs and PE films than in the control plots at the beginning of the experimental period, but there was no consistent difference in soil temperature towards the later part of the experimental period. Therefore, the BFs used in this study were shown to be helpful without causing negative impacts on the growth and yield of com.

• Journal of the Korean Society of Tobacco Science
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• v.4 no.1
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• pp.43-49
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• 1982

This experiment was carried out to study the influence of temperature on the growth rate and nutrient uptake of tobacco seedlings grown on neutralized charcoal bed during temporary transplanting. The highest growth rate was obtained at tile temperature of 26-22-$l8^{\circ}C$, probably due to fast establishment of roots in the soil. Seedling growth was better in neutralized charcoal bed than in chaffy charcoal bed at each temperature. Days required for fresh weight to reach 20g/10p1ants were shortened by 9~12days as the temperature increased from 18-14-$l0^{\circ}C$ to 26-22-$l8^{\circ}C$. Compared with chaffy charcoal bed, days required for fresh weight to reach 20g/10 plants with neutralized charcoal bed were shortened by about 5 days, 4 days, and 2days at 18-14-$l0^{\circ}C$, 22-18-$l4^{\circ}C$, and 26-22-$l8^{\circ}C$, respectively. Three macronutrient (N, $P_2O_5,\;K_2O$) contents in seedlings increased with increase of temperature. At each temperature, N and $K_2O$ contents in seedlings of neutralized charcoal bed was higher than those of chaffy charcoal bed, whereas that of $P_2O_5$ was low conversely. Nitrate nitrogen from nitric acid that was used to neutralize chaffy charcoal was maintained to tile end of seedling period, providing the source of nitrate nitrogen for the better seedlings.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.3
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• pp.185-190
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• 2003

This study was conducted to examine rice growth duration by analyzing agricultural climatic conditions at different latitudes in unified Korea. The climatic conditions of nine sites from Wunggi (latitude 42N) to Jeju (latitude 31N) were examined in this study. The rice growth duration of various cropping patterns was determined by analyzing consecutive days when effective daily mean air temperature was suitable for rice growth from the first seeding date to the last maturing date. The rice growth duration in Wunggi located in North Korea was available 138 days for machine transplanting, 115 days for direct seeding on dry paddy cultivation, and 97 days for direct seeding on a flooded surface with cultivation after seeding. On the other hand, the rice growth duration in Kwangju (latitude 35N) located in South Korea was 195 days for machine transplanting, 180 days for direct seeding on dry paddy cultivation, and 170 days for direct seeding on a flooded surface cultivation after seeding.