• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.184-184
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• 2017

Organic matter is very important and essential factor to maintain productivity of paddy field. But as meat consumption and the demand of grain increase, the demand of forage also increased gradually in Korea. So the amount of organic matter in paddy field have been declined gradually by the reduction of return of rice straw for the forage use for cattle. There is not enough alternative resources for forage, we guess this trend of organic matter decline in paddy field would continue for the time being in Korea. So this study was performed to confirm the variation of organic matter and change of rice yield to select suitable rice cultivars which yield reduction is small in condition of organic matter decrease in paddy field. To confirm the change of rice growth and yield in condition of organic matter decrease in paddy field, we transplanted 10 rice cultivars which yield reduction are small in low fertilizer condition. We transplanted it Buan where double cropping of winter barley continues several years on June 10. Planting density were $70plants/3.3m^2$ Fertilizer amount was $N-P_2O_5-K_2O=9-4.5-5.7kg/10a$ and fertilizer split application of nitrogen was basal-tillering stage-panicle initiation = 50-20-30%. And in the other cultivation management, we observed rice standard culture of NICS. In paddy field where withdraw straws of barley and rice, the organic matter content showed tendency to decrease as the years go on. During rice cultivation season, organic matter decreased little by little, but it increased again after rice harvest season. Rice yield was more in order of Sodami, Chunghaejinmi and Saenuri. We judge that there is an advantage in rice yield of rice cultivars which have later heading date because of suitable ripening temperature. Although Sobibyeo and Shindongjinbyeo showed high yield, head rice yield decreased severely owing to chalky and cracked rice.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.104-104
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• 2017

Sorghum (Sorghum bicolor (L.) Moench.) is one of the most important crops for human and animal nutrition. Nonetheless, sorghum has a cyanogenic glucoside compound which can be degraded into hydrogen cyanide, toxic to humans and animals even with tiny amount. In consequence, breeding materials with a low cyanide level has been a top priority in sorghum breeding programs. To fulfill our long-term goal, we are screening sorghum accessions with low cyanide level, which would be an important breeding material for food safety. We collected seeds of various sorghum accessions and analyzed relevant metabolites to find useful breeding materials of sorghum accessions containing low cyanide. Fourteen wild relatives were obtained from the University of Georgia in US, a reference accession BTx623, and three local varieties from National Agrobiodiversity Center of Rural Development Administration in Korea, and one wild species from the Wild Plant Resources Seed Bank of Korea University in Korea. Sorghum plants were grown in plastic greenhouse under natural conditions. After growing, leaf samples were harvested at different developmental stages: seedling phase, vegetative phase (right before flowering), and reproductive phase (ripening). Using collected samples, quantification analysis were performed by an HPLC system for three metabolites (dhurrin, 4-hydroxybenzaldehyde, and 4-hydroxyphenylacetic acid) in sorghum plants. Prior to metabolome analysis, specific experimental condition for HPLC system was set to be able to separate three metabolites simultaneously. Under this condition, these metabolites were quantified in each accession by HPLC system. We observed that the metabolite contents were changed differently by developmental stages and accessions. We clustered these results into five groups as patterns of their contents by developmental stages. Most of accessions showed that 4-hydroxybenzaldehyde content was very high at seedling stage and decreased rapidly at vegetative phase. Interestingly, the patterns of dhurrin content were very different among clusters. However, 4-hydroxyphenylacetic acid content was maintained at low levels by developmental stages in most accessions. The results would demonstrate how dhurrin and alternative degradation pathways are differentiated in each accession.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1296-1302
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• 2013

The quality of fresh jujube (Zizyphus jujuba) fruit rapidly declines in the postharvest stage and thus the effective storage conditions for agricultural warehouses were investigated in this study. Fresh jujubes (~10 kg) were stored using five different storage methods: plastic box without further packaging as a control (C-PL), plastic box with hanji packaging (H-PL), plastic box with functional film packaging (F-PL), cardboard box with hanji packaging (H-CB), and cardboard box with functional film packaging (F-CB). The storage boxes were stored in a refrigerator ($0^{\circ}C$ and 80~90% RH), equipped with an ethylene gas scavenging device for 9 weeks and then the quality characteristics were analyzed. The control storage conditions of jujubes showed a substantial decline in quality with decreases in moisture content, hardness, and sugar content as well as increases in decay ratio and redness. Among the tested storage conditions, F-CB was most effective in terms of maintaining the quality of jujube fruit while maintaining firmness, weightlessness, ripening degree from redness and visible appearance. In conclusion, effective storage and packaging conditions during storage enabled maintenance of fruit quality of jujubes for 9 weeks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5417-5422
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• 2013

This research was performed in order to improve the goodness of fit of paddy rice production forecasting using MODIS images and to find out appropriate explanatory variables in the forecasting model. The aim of this paper is to review the use of satellite images for the survey of paddy rice production in Korea. Many developed countries, including the United States, Australia, and Japan, have been using satellite images to produce agricultural statistics such as crop production, cultivated acreage, etc. The survey accuracy of crop production by using satellite images, however, is not satisfied in practical use. In this paper, we reviewed several methods to increase the survey accuracy of rice production statistics, gained from satellite images. Rice was selected for this study because its cultivated area and production amount could be more easily identified than other crops by using satellite images. The MODIS images were used because they involved more appropriate images to estimate and analyze rice production. This study estimated yield functions by using the NDVIs, gained from paddy rice yields and annual average isothermal lines, and the meteorological variables such as sunshine hours, rainfall, and temperature during ripening stage. As a result of yield function estimation, the goodness of fit(R-squared) for the models was shown from 0.768 to 0.891. In this study, it is noteworthy academically and practically that vegetation index(NDVIs) identified by annual average isothermal lines and meteorological variables are very useful for estimating yield functions.

• Korean Journal of Organic Agriculture
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• v.21 no.3
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• pp.381-389
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• 2013

In order to study the effect of organic fertilizer on dry matter (DM) yield, nitrogen fixation and transfer from pea to barley, an experiment was carried out from May to June in 2008 in Incheon. A completely randomized block design with three replications was used for the experiment and one reference plot assigned each treatment for nitrogen fixation evaluation. Seeding mixture was 40kg barley and 80kg pea per ha. N rate of 40, 80 and 120kg/ha as organic fertilizer was applied at seeding. The equivalent of 1kg per ha as $(15NH_4)_2SO_4$ Solution at 99.8 atom N was applied to the plots ($30{\times}20cm$) at mid April. Forage was harvested from each plot in ripening stage at ground level and separated into barley and pea. Nitrogen fixation was 32.4%, 23.4% and 0% at three different organic N levels. Transfer rate were from 47.6% to 21.8% in difference method and 24.6% and 21.4% on $^{15}N$ dilution method. N Transfer amount were from 92.8kg/ha to 41.9kg/ha on difference method and 47.3kg in the 40kg N plots and 49.7kg in the 80kg N plots on $^{15}N$ dilution method but there was no N transfer in 120kg N organic fertilizer plots. Benefit from increased organic fertilizer was not clear in terms of nitrogen fixation and transfer from pea to barley in barley and pea mixtures.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.475-487
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• 2017

The aim of this study was to solve the problem of yield loss causing the lag of fertilizer efficiency after tiller stage, being originated by applying mixed expeller cake fertilizer on three day before rice transplanting in organic rice farmers. The mineralization degree of $NH_4-N$ of the mixed expeller cake fertilizer was increased until 7 weeks at flooding condition, and so did $NO_3-N$ until 5 weeks at non-flooding condition. The mineralization rate of nitrogen in paddy soil on 20 days before rice transplanting was the highest by 0.85% on 20 days before the transplanting treatment. The properties of yields during the harvest period have no difference with application time of the mixed expeller cake fertilizer, except soil organic matter. The plan length, culm length and panicle length were the longest on 20 days before rice transplanting. Also, the number of tiller, ripening rat and 1,000 grain weight were the highest on 20 days before rice transplanting, and thereby the yield of white rice were increasing by 9% on 20 days before rice transplanting compared with that of 3 days before rice transplanting. The whiteness values of the rice and amylose content made no difference, but the value of protein and palatability were the same between 20 days and 30 days treatment. In the conclusion, the relationship between rice yield, its quality and application time of the mixed expeller cake fertilizer has showed that the suitable time of applying it reveals 21.3 days before rice transplanting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.163-172
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• 1987

Results obtained from this study conducted to find the effect of wind-break net on reducing cold wind damage in the eastern coastal cold wind damaged area are summarized as follows. The rice critical safe heading date was up to Aug. 10 in the eastern coastal area, which the frequency of gale Aug. 10 to Sep. 10 is high. The frequencies of westries and cold wind from sea were 25%, respectively, in this area. The effects of wind-break net on reducing wind verocity were 26.9, 34,6% with raising air temperature of 0.4-0.7$^{\circ}C$ and water temperature of 0.3-0.5$^{\circ}C$. The effect of wind-break net was up to 10 time's distance of wind-break net's height from wind-break net. The installation of wind-break inhanced to rice growth, so showed the heading date earlier by 2-5days and increased culm length, no.of panicles per hill and no. of spiklets per panicle. The yield decrease in this area was due to sterilization, poor ripening and light 1,000 grain weight. The yields showed 20-28% increase by installation of wind-break net. The effect of wind-break net was most in the installation plot with wind-break net against cold wind from sea and westries installed in the panicle formation stage.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.421-426
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• 1999

This study was conducted to examine the quality of low-salt Mul-kimchi which was prepared by mixing of radish (25%), green onion (2.4%), red pepper (1.9%), garlic (1.9%) and salt (0, 0.2, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0%) in water and followed by fermentation at 4, 15 and $25^{\circ}C$ for 10 days, respectively. The pH was lowest and acidity was highest in the Mul-kimchi containing 1.0% salt. The total vitamin C contents in Mul-kimchi containing $0{\sim}0.2%$ salt were high at the early stage of fermentation while those of Mul-kimchi containing 3.0% salt were higher than the low-salt samples after the optimal ripening time. The hardness of the radish increased with the salt concentration. Overall palatability of Mul-kimchi showed the highest score in 1.0% salt sample.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.285-291
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• 1996

The effect of various packaging methods on Kimchi quality was investigated in order to develop the packaging techniques for preventing commercial Kimchi Products from ination and explosion due to fermentative gas evolved during storage and distribution. Kimchi was packaged in different methods; atmospheric (AP), check-valved (CV), double (DP) and vacuum (VP) packaging. The quality of Kimchi during storage at $10^{\circ}C$ was evaluated ill terms of gas composition, free volume, pH, titratable acidity, color index, lactic acid bacteria and sensory properties. $O_2$ concentration decreased to about 1% at $6{\sim}8$ days of optimal ripening time in all packages except DP, in which it remained around 20%. $CO_2$ concentration reached $70{\sim}90%$ after $6{\sim}8$ days in AP, CV and DP, while it stayed around 10% in DP. The free volume in AP had typical sigmoidal curve similar to $CO_2$ concentration changes. It remained almost constant in CV and DP, but started to increase at the late stage of storage In VP. There was no significant influence of packaging methods on the other quality attributes such as pH, titratable acidity, color index (L.b/a), lactic acid bacteria count and sensory evaluation score. As results, it could be proposed to employ CV and DP method as the effective packaging techniques for preventing commercial Kimchi products from inflation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.2
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• pp.125-136
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• 1981

This experiment was conducted to study the influence of different cultivation periods on some morphological and agronomic characteristics of rice plant at Iri, the Honam plain, in 1979. Early maturing varieties showed little delay in heading with late transplanting, but intermediate and late maturing varieties showed more than 7 day delay in heading. The number of days required to reach heading was over 55 and 67 days after transplanting in early and intermediate-late maturing varieties, respectively. There was significantly postitive correlation between the length of vegetative stage and the grain yield. The mean temperature during ripening period was significantly correlated with the grain yield and the percentage of filled grains. The length, width, and thickness of leaf increased with earlier transplanting and the elongation degree between upper and lower leaves showed the same tendency. The productivity of dry matter and the translocation rate of photosynthate to spikelet decreased with late transplanting mainly due to low temperature. LAI was also influenced by transplanting date showing close correlation with yield. Early transplanting was desirable for assimilation and dry matter accumulation.