• Korean Journal of Soil Science and Fertilizer
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• v.34 no.1
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• pp.64-70
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• 2001

To verify the newly developed decision assisting expert system for nitrogen fertilizer application NES to Illinois cornfields, a couple of N rate studies from Dr. Howard and five Illinois Agricultural Experiment Stations were applied. Four types of recommendations including the current Illinois recommendation, Hoeft recommendation, NES, and maximum economic recommendation were compared with each other for the crop yields, profits, recovery rate, and N losses to cornfields. The N rate of NES recommendation, considering productivity index (PI), soil organic matter content (SOM), and pre-sidedressing nitrate concentration (PSNT) level, was the lowest in comparison to those of other recommendations. However, N recovery rate in NES was generally higher and the resulting N loss was lower than others. But, adherence to the recommendations may also reduce farmers income if environmental expense did not considered. Therefore, NES will be more effective by adding the factors including environmental expense, tillage systems, crop rotation, and other agricultural management parameters.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.1
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• pp.55-63
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• 2001

N fertilizer recommendations to optimize with consideration to maximum crop yields, maximum profits, and minimum N losses to ground or runoff water, an advisory system. Nitrogen Expert System (NES), was developed. The system was to estimate the optimal rate of N fertilizer application cornfields in Illinois. NES was constructed using Smart Elements, a knowledge-based system that manages the expertise of human experts. NES was reinforced by addition of the effect of a productivity index (PI), soil organic matter content (SOM), and pre-sidedressing of nitrate concentration (PSNT) to the optimal N fertilizer recommendation. NES contains 49 rules, 1 class, 14 objects, and 2 properties. NES was successfully operated, showing N recommendations with inputs of three soil properties including PI, SOM, and PSNT. NES can reduce N loss to the environment, but adherence to the recommendations may also reduce farmers income. Therefore, NES will be more effective by evaluating both environmental damage assessment and other economic agricultural management parameters and other soil physico-chemical parameters.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.379-384
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• 2009

This study was carried out to understand the national and regional distribution of the biomass resources produced in Korea annually via establishing database (DB) and distribution maps of biomass resources data including as livestock manures, food wastes and agricultural by-product. The information of the annual production of each biomass resources was obtained from Ministry for Food, Agriculture, Forestry and Fisheries (MIFAFF), Ministry of Environment (MOE) and National Statistical Office (NSO). Based on biomass resources data, we established database architecture table about livestock manures and food wastes. The distribution maps for the total amount of manures produced from each livestock animal were built up in both national and regional scales and used for analysis of the space-based and time-based distribution of the manure resources. Distribution maps for food wastes and agricultural by-product were also produced, respectively. It was shown that the analysis through resource mapping can be used to identify the sources of collectable biomass feasibly determining suitable region for establishment of a biomass-energy production. The biomass distribution maps graphically provide the information regarding biomass resources to policy-makers, farmers, general users and it was expected to be utilized for policy-making of environmental-friendly agriculture and bio-energy.

• Korean Journal of Environmental Agriculture
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• v.40 no.3
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• pp.169-178
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• 2021

BACKGROUND: The Ministry of Agriculture, Food and Rural Affairs is promoting agri-environment conservation program to induce farmers to participate in agricultural environment improvement and conservation activities. However, assessment tools based on scientific evidence are needed to determine the effectiveness of the program objectively and quantitatively. Therefore, this study was performed to develop plant indicators in order to efficiently evaluate the effects of the agri-environment conservation program promoted by the Ministry of Agriculture, Food and Rural Affairs. METHODS AND RESULTS: The survey was conducted in five regions (Hampyeong, Boryeong, Mungyeong, Hongseong, and Sangju) participating in the agri-eonvironment conservation program. In each region, twenty paddy fields were investigated (ten paddy fields included in the program and ten paddy fields not included in the program). A total of 231 taxa vascular plants were identified in the paddy fields that were included in the agri-environment conservation program, and a total of 177 taxa were identified in the paddy fields that were not included. The average species number occurred on each field was 55.8 taxa in the fields included in the program, and 35.0 taxa in the fields not included in the program. The difference in occurring plants between two groups was found to be more higher in perennial plants than in annual plants. We selected the six groups as indicator plants through five criteria such as perennial plants and broadly occurring species, etc. to verify the effectiveness of the agri-environment conservation program: Taraxacum spp., Ixeris spp., Viola spp., Platago spp., Calystegia spp., and rare and endagered species. There was a high positive correlation between the score calculated using these indicator plants and the total number of plants species. CONCLUSION: This study suggests that it is possible to evaluate the agro-ecological environment by using indicator plants. The selected indicator plants can be effectively used to verify the effectiveness of projects such as agri-environmental conservation programs in the future.

• Journal of Mushroom
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• v.16 no.4
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• pp.279-286
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• 2018

The button mushroom, Agaricus bisporus, is one of the most widely cultivated mushrooms. The domestic production of cultivated mushrooms in 2016 was approximately 10,173 tons, with a total value of 59 billion won. Currently, 10 cultivars have been developed; however, Korean farmers continue to demand new cultivars of mushrooms with improved quality. To breed superior lines, KMCC00754 and KMCC00775 were selected as mother strains from the 170 collected genetic resources. The putative homokaryotic strains were 25 strains from the 120 SSIs of KMCC00754 and six strains from the 120 SSIs of KMCC00775 selected by using the AbSSR45 marker. These homokaryotic strains were crossed with each other and the crossing was confirmed by SSR analysis. Seventy-four lines were crossed into 150 lines for a 50% ratio of crossing. Abs2-2015-16 was selected as a superior line by three cultivations. A new cultivar, 'Dodam', was developed in 2017.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.207-212
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• 2018

BACKGROUND: Recently, the need for a method to cultivate 'Haryejosaeng' Satsuma mandarin has been increasing. However, there is limited information available as this is a new Satsuma mandarin cultivar, which was bred by the RDA in 2004. Many farmers who cultivate this cultivar follow the cultivation method similar to that used for 'Miyagawa' Satsuma mandarin, and suffer low production of optimum-sized fruits. METHODS AND RESULTS: This study was conducted to find out the optimum ratio of leaf-to-fruit for the stable production of high quality 'Haryejosaeng' Satsuma mandarin fruits in a non-heated plastic film house. Seven-year-old 'Haryejosaeng' Satsuma mandarin trees were used in the study. Before the treatment, the leaf-to-fruit ratio ranged from 5.7 to 17.9. The treatments included 10, 20, 30, and 40 leaves per fruit. The fruits were removed if over fruiting was observed at day 60 after full bloom. We investigated the fruit size and quality on the day of harvest. Flowering and fruiting patterns in each treatment were recorded for the following year. In the experiments, the flower-to-leaf ratio was 1.12 to 1.74. As the leaf-to-fruit ratio decreased, the fruit size and weight also decreased. Contrarily, the higher the ratio of leaf-to-fruit, the higher fruit size and weight were. It was noted that the ratio of 20:1 was ideal to produce the M grade optimum-sized Satsuma mandarin fruits on the day of harvest. However, higher ratio might result in fruits weighting above 100 g. There was no difference among the treatments in terms of fruit quality, such as total soluble solid contents, titratable acid, and color. In the subsequent years, flowering and fruiting in the treatments were lowered when the leaf number per fruit was 10, but they were improved when the leaf number per fruit was above 20. CONCLUSION: Based on the above results, the optimum ratio of leaf-to-fruit was found to be 20:1 for flowering and fruiting of 'Haryejosaeng' Satsuma mandarin. It is important that optimum ratio of leaf-to-fruit is set as a standard to produce good grade and quality of 'Haryejosaeng' Satsuma mandarin fruits.

• Korean Journal of Heritage: History & Science
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• v.42 no.4
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• pp.132-151
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• 2009

Gut (Shaman ritual) in the west coast area is consisted to sanyang-geori (hunting), tasal-geori, gunwoong-geori those describe from hunting process to preparing animal sacrifices to a deity. The characteristic of gut in the west coast area which are represented for mock hunting and animal sacrifice ritual is practicing at the sibamasturi in Japan. This paper aims to compare a shaman ritual in west coast area in Korea and Japanese Sibamasturi from the comparative folklore point of view. Gut in the west coast area is well known for dividing sacrificial offering: vegetable for sinryeong and meat for singyeong. This division of spiritual deity shows it has different background from agriculture and hunting culture. Hwanghae-do gut has been formed under the various life environments. Therefore, each stage is conducted according to the purpose of the ritual. Sanyang-geori (hunting) represents the scene of hunting in the mountain and by catching live animals and it refers to Gunwoonsin, and will be offered. Animal sacrifice is a positive ritual which get rid of bad luck and pleased deity. Sibamasturi is practiced in mountain area where most of people involve in hunting and agriculture. Therefore, this area has both agricultural ritual and hunting ritual. Sibamasturi is practiced in January (lunar) and it also has meaning of beginning of agriculture and hunting in mountain area. Ground burnt off for cultivation way symbolizesfire ritual and mock hunting as well as animal sacrifice together. These rituals match to farmers of mountain area in the south-east Asia. The gut in the west coast area and Japanese Sibamasturi have common point that mock hunting and animal sacrifice are practiced at both rituals, however, the structure for these two ritual are different. In other word, there animal sacrifice has been formed with different cultural back ground.

• Journal of Mushroom
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• v.17 no.3
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• pp.167-170
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• 2019

Cultivation of brown mushrooms, rather than that of white variants is preferred by Korean mushroom farmers, as the former are resistant to diseases. However, brown mushrooms were cultivated only in selective eco-friendly agricultural farms due to lack of consumer awareness. After providing information about brown mushrooms to respondents through a 1-minute video clip, a survey was conducted on social network service (SNS) to assess recognition and preference for brown mushrooms. A food evaluation was then conducted among 200 people randomly selected from the survey respondents. Most respondents (83%) had not encountered brown button mushrooms previously, and 98% of the respondents were willing to buy these mushrooms because they were "curious about its taste" (44%). In the food evaluation, 32% of the respondents found the brown button mushrooms to be delicious, 28% reported a good flavor, and 31% described a good texture. In addition, we confirmed that 95% of respondents were interested in purchasing brown mushrooms after sampling. Therefore, in the present study, we evaluated public perception, preference, and taste of brown button mushrooms, and confirmed that availability of information on nutrition and benefits s of mushroom consumption could induce consumers to buy brown button mushrooms.

• ALGAE
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• v.34 no.3
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• pp.237-251
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• 2019

The dinoflagellate genus Alexandrium is known to often form harmful algal blooms causing human illness and large-scale mortality of marine organisms. Therefore, the population dynamics of Alexandrium species are of primary concern to scientists and aquaculture farmers. The growth rate of the Alexandrium species is the most important parameter in prediction models and nutrient conditions are critical parameters affecting the growth of phototrophic species. In Korean coastal waters, Alexandrium affine and Alexandrium fraterculus, of similar sizes, often form red-tide patches together. Thus, to understand bloom dynamics of A. affine and A. fraterculus, growth rates and nitrate uptake of each species as a function of nitrate ($NO_3$) concentration at $100{\mu}mol\;photons\;m^{-2}s^{-1}$ under 14-h light : 10-h dark and continuous light conditions were determined using a nutrient repletion method. With increasing $NO_3$ concentration, growth rates and $NO_3$ uptake of A. affine or A. fraterculus increased, but became saturated. Under light : dark conditions, the maximum growth rates of A. affine and A. fraterculus were 0.45 and $0.42d^{-1}$, respectively. However, under continuous light conditions, the maximum growth rate of A. affine slightly increased to $0.46d^{-1}$, but that of A. fraterculus largely decreased. Furthermore, the maximum nitrate uptake of A. affine and A. fraterculus under light : dark conditions were 12.9 and $30.1pM\;cell^{-1}d^{-1}$, respectively. The maximum nitrate uptake of A. affine under continuous light conditions was $16.4pM\;cell^{-1}d^{-1}$. Thus, A. affine and A. fraterculus have similar maximum growth rates at the given $NO_3$ concentration ranges, but they have different maximum nitrate uptake rates. A. affine may have a higher conversion rate of $NO_3$ to body nitrogen than A. fraterculus. Moreover, a longer exposure time to the light may confer an advantage to A. affine over A. fraterculus.