• Journal of Korean Society of Forest Science
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• v.103 no.2
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• pp.264-269
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• 2014

The aim of this study was to determine the current distribution area of Robinia pseudoacacia habitat and to estimate its stand yield as well as its carbon stocks. In order to do so, the area of R. pseudoacacia distribution is obtained based on the large-scaled forest type map (1:5,000). Also, Weibull diameter distribution model is used to predict the yield of R. pseudoacacia stands. In addition, carbon emission factor is applied to calculate carbon stocks and removals. To obtain the stand yield of R. pseudoacacia, we developed estimation equation considering growth factors of the stand, e.g. mean diameter, the basal area, maximum and minimun diameter and etc. and tested it to ensure accuracy. Consequently, estimation equation derived from all growth factors have shown significance that could also be used for analysis. Site index was also established to determine the productivity of the forestland that later turned out to be ranging from 16 to 22. Based on these results, stand yield tables were drawn up. R. pseudoacacia is widely distributed in inland areas of Gyeongsang, Chungcheong and Gyeonggi provinces which covers total area of 26,770 ha. And when it is converted into carbon stocks, it amounts to 2,517,598tC with annual carbon uptake of 3.76tC/ha which is comparable to Querqus species that is known to storer large amounts of carbon. Therefore, R. pseudoacacia is also expected to serve as a viable carbon pool that would contribute to the mitigation of climate change. Furthermore, stand yield tables, an outcome of this survey would assist not only in proper management but also in sustainable management policy of R. pseudoacacia.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.55-58
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• 2004

The objective of this study was to get information about water retention characteristics of horticultural substrates used in Korea determined by European standard method. Water retention curves were prepared at water volume (v/v, %) in relation to -10 cm, -50 cm, -100 cm water pressure head. Water retention curves showed different properties depending upon the type, the place of origin, particle size, and manufacturing processes of substrates. Peat and coir had easily available water content in the range of 30-40% and showed high water holding capacity, water buffering capacity, and aeration for plant growth. However, bark, sawdust and rice hull showed low water holding capacity about below 10%. The easily available water content of perlite and clay ball was low about 0.1-13.8%, whereas that of vermiculite and rockwool granulate was high about 25.9-52.0%. Understanding water retention characteristics of growing substrates is very important in cstablisliing optimum condition for plant growth. Further study on water retention curves for more substrates, mixture and growing media is needed.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.4
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• pp.309-313
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• 1997

Field experiments were conducted on Jeonbug series (Fine silty, mesic family of Aeric Fluventic Haplaquepts), to study the effect of split application of N fertilizer in combination with rice straw on N use efficiency of dry-soil-direct seeded paddy rice. Treatments involved conventional application of N (in three splits; 40% at planting, 30% at five leaf stage and at heading stage) without rice straw, all basal application of N with straw application (5000 kg/ha), N application in two splits (70% at planting and 30% at heading stage) with rice straw application and N application in three splits (40% at planting, 30% at five leaf stage, 30% at heading stage) with application of rice straw. There was Zero N plot too for the estimation of N use efficiency. Seeding was done on dry soil and the filed was flooded 32 days after seeding. The fertilizer application rates were 160, 70, and 80 kg/ha of N, $P_2O_5$ and $K_2O$, respectively. The experiment was conducted for two years, in the same filed. The apparent use efficiency of fertilizer N by rice tended to be higher under the application of rice straw when N was applied in three splits. This, however, did not increase the yield of rice significantly. Even under the application of rice straw, the apparent N use efficiency was lower when N fertilizer was applied in one dose at the planting and in two splits. The lower N use efficiency in these cases, did not yield of rice significantly. The periodical analysis of mineral N in the soil suggested that higher mineral N in the soil at the early stages was responsible for the lower apparent N use efficiency.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.475-481
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• 1996

This study was carried out to acquire the basic information of root growth under different pot size, imposing different space limitation on rhizosphere. Different size of pots that had same surface area but different depth, 5cm(Iength)$\times$5cm(width)$\times$30, 15, 5cm(depth), were used during the seedling stage of tobacco plant. Space limitation on rhizosphere affected not only the aerial growth, stem height, leaf area and shoot dry weight, but also root growth and root architecture. Aerial growth was highly related to growth of underground part, so space limitation on rhizosphere decreased aerial growth. Limitation on pot volume by reducing pot depth induced new rooting on crown. Root number and relative multiplication rate were higher in small pot that had 5cm depth than large pot, but total root length and mean extension rate showed reverse patterns. Root numbers of 1st order and 2nd order were increased as pot depth was increased, but the root number of 3rd order was increased in small pot. Root system of seedling grown in large pot distributed more horizontally than that in small pot at 20 days after temporary planting (DAT), but the root architecture of seedling was reversed at 25 DAT.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.215-221
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• 1988

The hop yield prediction model developed based on meteorological elements in Hoeongseong was Y=6,042.846-17.665 $X_1$-0.919 $X_2$-96.538 $X_3$-138.105 $X_4$＋86.910 $X_{5}$ ＋ $X_{6}$ with MS $E_{p}$ of 25.258, $R_{p}$$^{2}$ of 0.9991, R $a_{p}$$^{2}$ of 0.9962 and $C_{p}$ of 7.00. The minimum air temperature at early growing stage ( $X_1$), the total precipitation at cone ripening stage ( $X_2$), the maximum air temperature at flower bud differentiation stage ( $X_3$) and the maximum air temperature at flowering stage ( $X_4$) influenced on hop yield as decrement weather elements. The average air temperature at early growing stage ( $X_{5}$ ) and the total sunshine hours at cone development stage ( $X_{6}$ ) influenced on hop yield as increment weather elements.lements.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.236-241
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• 1988

The responses of GA$_3$ treatment on the culm length, internode elongation, number of internodes elongated and on the panicle length of 115 Japonica rice cultivars were studied. One spray with 50 ppm GA$_3$ was made at about 30 days before heading. Generally short culm cultivars showed better elongation responses than taller ones and a few taller cultivars showed reduced culm length. The internode length of 1st, 5th, 6th and 7th were increased, but, 2nd, 3rd and 4th internodes were reduced. Especially the reduction of 3rd internode elongation and the increase of 5th internode length was prominent. Most of the tested cultivars showed no changes in the number of internodes elongated, but, in some cultivars it was increased and in a few ones it was reduced. The effect on the panicle length was variable depending cultivars. No significant correlation was found between the culm length elongation and the elongation of panicle length, implying that the response of GA$_3$ on the culm and on the panicle is independent of each other. According the response of culm length elongation tested cultivars were grouped into 6 ; Significantly reducing, slightly reducing, less sensitive, slightly elongating, largely elongating and extremely elongating.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.262-266
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• 2003

The present study was carried out to investigate the relationships among intertillage and muddying by free-ranging ducks (Chinese native ducks) and pH, dissolved oxygen of irrigation water, and physicochemical properties of soil. Two paddy fields comprised of the muddying (muddy water without physical stimulation to a rice plant by the ducks) and the control plots (no ducks) were used for this study. As a muddying plot, 50 hills were randomly selected and each hill was fenced with a wire net in order to prevent from stimulating physically by the ducks. The variation in irrigation pH was smaller in the muddying plot than the control plot, and the pH was around 7.4. Dissolved oxygen was significantly higher (P＜0.01) in the muddying plot than the control plot during the first half period after the ducks were introduced. Then it decreased rapidly as the rice plants grew in all plots. The contents of the suspended soil and turbidity in irrigation water were not changed over the free-ranging period, but $\textrm{NH}_3\textrm{-N}$ and $\textrm{P}_2\textrm{O}_5$ were decreased by intertillage and muddying by the ducks. There were no differences in both the soil physics and chemistry between the muddying plot and the control plot during and after finishing of the free-ranging period. These results indicate that intertillage and muddying by the ducks resulted in a small variation in stagnant water pH, and reduced the dissolved oxygen and $\textrm{P}_2\textrm{O}_5$, although the physiochemical properties of soil were not changed.

• Microbiology and Biotechnology Letters
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• v.28 no.2
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• pp.117-123
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• 2000

The object of this work is to improve the maintenance of bioluminescence from stored Photobacterium phosphoreum in a view of developing continuous monitoring system for pollutants. The long-term experiments were performed to determine the effect of storage temperature and immobilization on the maintenance of bioluminescence and viability of P. phosphoreum. A naturally luminescent bacterium, P. phosphoreum was starved in 2.5% Nael solution at $20^{\circ}C$, $4^{\circ}C$, -$20^{\circ}C$ and -$70^{\circ}C$ for 30 days. In vivo luminescence was measured by luminometry, and total cell concentrations and concentrations of culturable and viable cells were determined by acridine orange staining, dilution plate counting, and direct viable counting, respectively. The bioluminescence emission from cells stored at 4De was maintained up to 10 days while those with starved cells at other temperature ranges decreased to background level within 3 days. In terms of viability of cells, concentrations of cells stored at $20^{\circ}C$ were rapidly decreased as a result of cell lysis, leading to a drop in culturable and viable counts while cells stored at $4^{\circ}C$ was shown viable but nonculturable state during starvation. With immobilized cells on strontium alginate, the bioluminescence showed higher maintenance than free cells and decreased with count number of nonculturable cells.

• Applied Biological Chemistry
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• v.45 no.4
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• pp.207-211
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• 2002

This study was conducted to increase the shelf life of grape by edible coating material such as methyl cellulose (MC) with antimicrobial substances, n-capric acid isopropyl ester (ci) and sodium nitrate (sn), added by spraying method. The quality changes of packaged grapes with wrapping PE film on EPS tray were investigated for 16 days at $30{\circ}C$. The shelf-lives of C and MCci based on the weight reduction ratio of 7% were 6 days and 9 days, respectively. The reduction rate of acidity of C was higher value than those of treatments during 18 days of storage at $30{\circ}C$. The vitamin C reduction ratios of C, MCsn and MCci were 64.8, 51.5 and 49.8%, respectively, after 16 days at $30{\circ}C$. The reduction rates of firmness of C, MCsn and MCci after 16 days at $30{\circ}C$ were 44.2, 26.5, and 23,2%, respectively compared to that of initial storage grapes. The additions of ci and sn had much affected the reductions of bacteria and yeast counts especially early stage of storage. The hedonic sensory evaluation scores of MCci and MCsn had higher values than those of MC.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.329-332
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• 2003

The effect of garlic addition on quality and shelf-life of soybean curd was investigated. The yield of garlic soybean curd slightly decreased in proportion to amount of garlic added. In the case of texture, hardness of the garlic soybean curd increased when $5{\sim}10%$ garlic was added, whereas hardness, adhesiveness, cohesiveness, springiness and chewiness significantly decreased in the case of 20% garlic added. Microbial counts of soybean curd stored in sterilized distilled water as tofu-immersion solution increased, whereas pH decreased during storage at $15^{\sim}C$. During all storage periods, microbial counts of the soybean curds containing garlic were always lower than that of the ordinary soybean curd. These results imply that garlic is a useful additive in suppressing the proliferation of aerobic microorganism and has a potential use in extending the shelf-life of soybean curd. According to yield, textural properties and shelf-life data, the suitable concentration of garlic was around $5{\sim}10%$.