• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.9-15
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• 1998

A survey was conducted to investigate the chemical properties of soils such as pH, electrical conductivity, total organic matter content, soluble nitrate, available phosphate and major exchangeable canons, in plastic film houses at 513 sites. All the parameters surveyed in the plastic film house were much higher than those of open field soils. Particularly conspicuous was the accumulation of available P, exchangeable K and the occurrence of nitrate at relatively high concentration in both top soil(0-20 cm) and sub-soil(20-40 cm). In 70-80% of cases, the contents of available P and exchangeable K in top soils, were found to be higher than optimum levels. There was positive linear correlation between the content of exchangeable rations, and nitrate and EC of soils. The correlation coefficient was greater in the order of nitrate-EC > Mg-nitrate > K-nitrate > Ca-nitrate. The successive cultivation of horticultural crops in the plastic houses tended result in the accumulation of available P, exchangeable K and total organic matter in the soil.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1118-1123
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• 2011

The changes of available silicate (Avail. $SiO_2$) contents in paddy soils (sandy loam) were assessed from data of the 41 years fertilization plots in which the continuous rice cropping experiment started in 1954 at the National Academy of Agricultural Science. The treatments were no fertilization (O), inorganic fertilization (NPK), inorganic fertilizer plus rice straw compost (NPK+C), inorganic fertilizer plus silicate fertilizer as a soil amendment (NPK+S), inorganic fertilizer plus rice straw compost and silicate fertilizer (NPK+CS) and inorganic fertilizer plus rice straw compost, silicate fertilizer and lime (NPK+CSL). Available silicate contents in NPK+S, NPK+CS and NPK in surface soil reached at the highest content ($255{\sim}330mg\;kg^{-1}$) after 41 years and then levelled off. Available silicate contents in subsurface soil (25~30 cm) were higher in NPK+C and NPK+S treatments than those in other treatments. Continuous application of silicate fertilizer affected significantly on the levels of available silicate in surface and subsurface soils. Silicate uptake of top rice was more increased by 98% in NPK+CS and NPK+CSL over NPK. Grain yield also increased by 37~47% in NPK+CS and NPK+CSL as compared to NPK. The combined applications of inorganic fertilizers with silicate as a soil amendment are recommended as the best fertilization practice for fertilizer use efficiency, enhancement of soil fertility status in the continuous rice cropping system in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.405-411
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• 2007

This study was carried out to measure insoluble phosphorus fractions content fixed in different soil type and isolate a superior phosphate solublizing bacteria(PSB) producing free phosphate in citrus orchard soil. Distribution of insoluble phosphate fraction ordered Al-P>Ca-P>Fe-P in the investigated citrus orchards. Insoluble phosphate fraction such as Al-P, Ca-P, Fe-P were higher in volcanic ash than in non-volcanic ash soil. A PSB with high holo zone in PDA-P medium isolated from citrus orchard soil. This strain identificated by MIDI system as Bacillus sphaericus. The optimum growth of pH and temperature were at 4~5, $30^{\circ}C$, respectively. When Bacillus sphaericus cultured at $25^{\circ}C$, 150 rpm condition in LB broth medium included different phosphate. Bacillus sphaericus produced free phosphate in the culture broth medium from tricalcium-phosphate(207.0 ppm), aluminium phosphate(324.5 ppm) and hydroxyapatite(334.8 ppm) and Phosphatase activity of Bacillus sphaericus was higher at $35^{\circ}C$ culture condition than that of $25^{\circ}C$. Two type preparation inoculated Bacillus sphaericus made with carrier materials such as Bentonite, $CaCO_3$, Sodium alginate. Density of PSB in this preparation conserved at $10^5c.f.u.\;g^{-1}$ level during storage in different temperature condition for 7 month. It also showed that free phosphate produced at PDA-P medium.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.451-455
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• 2009

Lilium lancifolium, which is one of the Korean native lilies, possesses several useful genetic characteristics such as growth vigor, bulbil formation and resistance to Fusarium. Hybridization was performed to insert useful traits of Asiatic hybrid "Dreamland" as the male parent with upward direction and dark brown spotless on the petal into L. lancifolium as the female parent. The rate of pollen germination of L. lancifolium and "Dreamland" were 30% and 60%, respectively. The pollen germination ratio of $F_1$ progenies at flowering date was 25-57%, which is between the parents'pollen germination ratio. The individual flowering time was between 113 days and 131 days after planting. Of 99% of all plants, the leaf shape index was more than five, which means that the leaf shape of $F_1$ plants is more influenced by female than male parent. The flower color was separated into four types. 51.5% of the progenies showed orange and 44.2% showed light orange, respectively. The colors seemed to be highly influenced by female parents. Mixed colors of parents, orange yellow and light yellow orange, were 3.1%, 1.2%, respectively. Flowering directions were segregated by three different ways, upside, side, and downside. Side direction, which is medium type between female and male parent, was 73%. All progenies showed lots of spot on petals except one offspring. The percentage of bulbil formation on leaf axil was 49.4%. Among those, the maximum number of bulbil formation was 25. The mean number of bulbil formation per plant was five.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.337-347
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• 2018

Weather causes much of the risk of agricultural activity. For efficient farming, we need to use weather information. Modern agriculture has been developed to create high added value through convergence with state-of-the-art Information and Communication Technology (ICT). This study deals with the quality control algorithms of weather monitoring equipment through Ubiquitous Sensor Network (USN) observational equipment for efficient cultivation of cabbage. Accurate weather observations are important. To achieve this goal, the Korea Meteorological Administration, for example, developed various quality control algorithms to determine regularity of the observation. The research data of this study were obtained from five USN stations, which were installed in Anbandegi and Gwinemi from 2015 to 2017. Quality control algorithms were developed for flat line check, temporal outliers check, time series consistency check and spatial outliers check. Finally, the quality control algorithms proposed in this study can also identify potential abnormal observations taking into account the temporal and spatial characteristics of weather data. It is expected to be useful for efficient management of highland cabbage production by providing quality-controlled weather data.

• Korean Journal of Environment and Ecology
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• v.35 no.4
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• pp.408-423
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• 2021

We established and monitored survey sites in seven regions of Mt. Jiri to investigate population decline and change of the Korean fir (Abies koreana) over a ten-year period from 2009 to 2018. With the exception of one site (Seseok), the six remaining ones all showed a four-layer stratification structure. The importance value of Korean firs in all of the survey areas decreased significantly by 28.5%, from 55.7% in 2009 to 39.8% in 2018. The average population of objects with a diameter at breast height (DBH) of 5cm or more in all survey sites was 711 objects/ha in 2018, and the cumulative death rate from 2009 to 2018 was 10.8%. Among the death types, DS (dead standing) was the most dominant, comprising 82.4% of the total survey area. However, in Banyabong 1, which had a high gradient of 35°, the death types other than DS accounted for 44.2%. We estimate that A. koreana can maintain a stable population as its distribution type for each diameter class in the Saeseokpyeongjeon site showed a reverse-J shape. The average annual ring growth in all survey sites was 1.09 mm/year, with the most abundant growth observed in the Seseokpyeongjeon site, which was formed mainly by a subtree layer. The growth ring survey showed the estimated average age of A. koreana population in the Byeoksoryeong and Banyabong 1 sites to be 102 and 91 years, respectively, a general downward trend of vitality since 2013.

• Journal of Plant Biotechnology
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• v.48 no.1
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• pp.62-70
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• 2021

We analyzed the growth and quality characteristics of barley sprouts grown under artificial light sources consisting of a fluorescent lamp or light-emitting diode (LED) in an aquaculture system (grown with water only, without nutrients). At the end of the observation period, the shoots grown under the fluorescent lamp treatment were the longest, followed by the LED treatment and natural light-treatment. It was also observed that growth was faster for sprouts subjected to a non-sterilizing treatment than those subjected to a 70% ethanol treatment. As the seed sowing rate for planting trays increased, the yield of harvested barley sprouts increased; among light treatments, the natural light treatment resulted in the lowest yield, while the fluorescent light treatment resulted in the highest. The total phenol and total flavonoid contents of extracts of the barley sprouts were highest for the natural light treatment, but TEAC and FRAP were both highest for the fluorescent lamp treatment. The essential amino acid content ranged from 41.64 to 45.93 mg/g and was relatively higher for the natural light treatment than the other two treatments, while the content of non-essential amino acids was highest for the LED treatment. The total amino acid content was highest for the LED treatment at 97.47 ± 6.30 mg/g, for which the content of non-essential amino acids (53.17%) was higher than that of essential amino acids (46.83%).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.524-535
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• 2020

This study was conducted to derive implications for the dissemination and expansion of subtropical crops in farms. To this end, the cultivation trends and main producing areas of promising subtropical crops in Korea were analyzed. Analysis results found that the cultivation area of crops, excluding mango, was stagnating or decreasing. The main producing areas of domestic subtropical crops are located on Jeju Island (mango, dragon fruit), in Gyeongsangnam-do (papaya), and in Jeollanam-do (turmeric). Guava and Yeoju could not define the main producing area. For all crops, the percentage of cultivated area in the top 10 regions was high, but only half of the regions maintained the ranking. These results imply that the introduction and abandonment of subtropical crops are frequent. The dissemination and expansion of subtropical crops are justifiable in terms of responding to climate change in the future and creating new income for farms. Therefore, government support policies and agricultural promotion agencies need to be established.

• Smart Media Journal
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• v.9 no.4
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• pp.176-186
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• 2020

The size and shape of crops are diverse, and the growing environment is also different. Therefore, when one uses a drone to spray pesticides, the characteristics of each crop must be considered, and flight conditions such as the flight height and forwarding velocity of the drone should be changed. The droplet flow of pesticides is affected by various flight conditions, and a large change occurs in the sprayed area. As a result, an uneven distribution of liquid may be formed at the wake, and the transport efficiency will be decreased as well as there would be a risk of toxic scatter. Therefore, this paper analyzes the degree of distribution of pesticides to the crops through numerical analysis when pesticide is sprayed onto the selected three crops with different characteristics by using agricultural drones with different flight conditions. On the purpose of establishing a guideline for spraying pesticides using a drone in accordance with the characteristics of crops, this paper compares the amount of pesticides distributed in the crops at the wake of nozzle flow using the figure of merit, and the sum of transported liquid rate divided by the root mean square of the probability density function.