• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.9-14
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• 2009

Applying livestock manure compost to soil can enhance soil fertility and crop productivity. However, little information is available on the effect of continuous application of manure compost on crop growth in Korea. The object of this study was to investigate the residual and continuous application effect of chicken manure compost on chinese cabbage yield and soil chemical properties. The experiment was conducted in the pot ($0.5\;m^2$) without bottom buried in the soil and set up in a completely randomized design with three replication. The treatment consists of chemical fertilizer with nitrogen (NPK, $N-P_{2}O_{5}-K_{2}O$ 320-78-198 kg/ha) and without nitrogen (PK, $N-P_{2}O_{5}-K_{2}O$ 0-78-198 kg/ha), and chicken manure compost at a rate corresponding to 320 (COM1) and 640 (COM2) kg N/ha. This experiment was carried out for three cropping seasons with chinese cabbage. Chemical fertilizer, NPK and PK, was applied every cropping season. In the first cropping season, compost was applied in nine pots (COM-A). In the second cropping season, compost was applied in the six pots of COM-A (COM-AA) and in three pots of COM-A compost was not applied (COM-AN). In next cropping season, compost was applied in the three pots of COM-AA (COM-AAA) and in the other three pots of COM-AA compost was not applied (COM-AAN). COM-AN pots remained without compost application in the third cropping season (COM-ANN). Yields of chinese cabbage of COM1-AAA and COM2-AAA were reached 78 and 96% as compared with NPK, and nitrogen utilization rate was about 85% (COM1-AAA) and 97% (COM2-AAA) as compared with NPK Residual N uptake rates during the second and third cropping season after compost application at the first cropping season were 49.7 (COM1-AN) and 35.6% (COM1-ANN) in COM1, and 56.9 (COM2-AN) and 37.4% (COM2-ANN) in COM2 compared with NPK treatment After three cropping seasons, soil pH and contents of available phosphorus, exchangeable potassium and soil organic matter were increased with continuous application of chicken manure compost.

• Korean Journal of Poultry Science
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• v.41 no.2
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• pp.115-125
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• 2014

With Single Comb White Leghorn (WL) and Korean Native Chicken (KNC) breeds, we compared the stress response with chicken breeds that were subjected to a high stocking density. Stress response was analyzed by the quantity of telomeric DNA, the rate of DNA damage and the expression levels of heat shock proteins (HSPs) and hydroxyl-3-methyl-glutaryl coenzyme A reductase (HMGCR) genes on tissues and blood. The telomere length and telomere shortening rates were analyzed by quantitative fluorescence in situ hybridization on the nuclei of lymphocytes and tissues. The DNA damage rate of lymphocytes was quantified by the comet assay. The expression levels of HSP70, HSP90-${\alpha}$, HSP90-${\beta}$ and HMGCR genes were measured by quantitative real-time polymerase chain reaction in lymphocytes. There was no significant difference between KNC and WL in body weight, weight gain, telomere shortening rate and DNA damage rate. However, the growth rate significantly decreased in chickens raised under high stocking density conditions, as compared to the control group. The telomere-shortening rate, DNA damage and HSPs expression of the lymphocytes were significantly higher in the high stocking density group than the control. The stress condition and breeds had a significant effect on the expressions of HSP70, HSP90-${\alpha}$ and HSP90-${\beta}$ in lymphocytes, except HMGCR. The stress response of WL was higher than that of KNC, as analyzed to the expression of HSP70 and HSP90-${\alpha}$. Therefore, we concluded that the chickens which were exposed to a high stocking density had increased the individual physiological stress response regardless of breeds, and White Leghorns are more susceptible to stress condition than Korean Native Chickens.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.38-43
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• 1992

A field experiment was conducted to find out the effect level of nitrogen fertilization on the yield and quality of hop (Hallertau variety) emphasis given to ${\alpha}$-acid content. Nitrogen was applied by the rates of 0, 12, 18, 24, 30 and 36kg per 10a. Results were summarized as follows. 1. Stages of cone-hair developing and coneripening were delayed with increment of nitrogen applied. Number of nodes and length of vine increased with nitrogen applid by up to 24kg N/10a. 2. Yield was the highest in the 24kg N/10a plot and cone weight had high significant correlations with yield without regard to the years of growth. No.of flower per side blanch and weight of 100 cones had a significant correlation with yield in the four-year old and five-year old Hop plants. 3. Nutrient content in Hop plants was in the order of CaO, total nitrogen, $K_2O$, MgO and $P_2O_5$. Content of total nitrogen, CaO and MgO was high in leaves while that of $P_2O_5$ and $K_2O$ was high in cone. Nitrogen, phosphorus and magnesium increased with increment of nitrogen fetilized while potassium and calcium decreased. 4. As for the distribution of nutrients in cone developing stage $SiO_2$ content was higher in lower part than in the upper part while $P_2O_5$ contetn was higher in upper part than in lower part of the plant. And content of nitrogen and potassium was higher in middle height than in upper and lower part. 5. The optimum levels of nitrogen application were 19.3kg for 2 years, 24.3kg for 3-year, 27.9kg for 4 years and 31.8kg/10a for 5-year old Hop, respectively. 6. Nitrogen uptake in cone showed a positive correlation with the content of ${\alpha}$-acid and ${\beta}$-acid in cone.

• The Korean Journal of Ecology
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• v.22 no.5
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• pp.287-294
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• 1999

During the period from April to October, 1998 the authors investigated the gall development process of Chinese gallnuts (Schelchtendalia chinensis) on sumac (Rhus javanica) at Mt. Goduk near Chonju city in Chonbuk province. The majority (56.8%) of chinese gallnuts were formed on first pinnates and 24.3% on second pinnates of sumac leaves. Galls began to form from the 1st of June and grew slowly until the 24th of June. Galls enlarged rapidly after the 1st of August, but their growth rates decreased after the 26th of August and stopped growing after the 8th of September. Alate viviparous females escaped from galls after the 24th of September. Fundatricies, the second generation in the galls, exuviated three times to become adults on the 24th of June. Fundatrix adults bore 1∼10 eggs in the body and laid 1∼16 nymphs of the second generation. Nymphs of the second generation began to appear on the 17th of June and had matured completely on the 14th∼24th of July. Adults of the second generation bore eggs in the body. Thus the developmental period of the second generation was 27∼37 days. Nymphs of the third generation appeared on the 14th of July and finally alate viviparous females were developed on the 24th of September. During the two months from the beginning of the third generation to the appearence of the final alate viviparous females, there should be at least two generations, that is, the third and fourth generations. The fourth generation seems to begin at about the 20th August because the number of inhabitants (2,859 individuals) in galls on the 26 th of August had increased more than 10 times those (263 individuals) on the 19 th of August. The tannin content of galls was 65.04∼68.23% while that of sumac leaves and stems was 11.56%, 3.49% respectively.

• Journal of Aquaculture
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• v.7 no.1
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• pp.21-39
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• 1994

In order to study the optimum environmental condition for larvae culture of the freshwater crab, Eriocheir japonicus, larvae from different growth stages and young crab were cultured under the 16 different conditions of $4\times4$ temperature-salinity combinations (4 different temperatures at 22, 24, 26, $28^{\circ}C$ with 10.5, 17.5, 24.5 and $31.5\%$ of salinity). The duration of metamorphosis, metamorphosis rate, the interval of moulting period, and survival rate were measured from each experimental group of larvae and young crab under the different conditions. The results indicated that the optimum conditions may be a $24.5\%o$ of salinity at water temperature at 22, 24, and $26^{\circ}C$. At $28^{\circ}C$ with $24.5\%o$), the duration of metamorphosis reduced somewhat, nevertheless metamorphosis and survival rate decreased a lot. And the lower the salinity showed the lower the metamorphosis and survival rates at $28^{\circ}C$.

• Journal of Aquaculture
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• v.20 no.4
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• pp.278-288
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• 2007

Shrimp culture in Korea had been rapidly developed during 1990's and the production of farmed shrimp reached 3,268 mt from 2,605 ha in 2001. However the shrimp production decreased to 2,368 mt in 2004 because of the mass mortality due to outbreak of white spot syndrome virus (WSSV). WSSV which is one of the most serious threats associated with cultured shrimp around the world has given the economic damages to shrimp culture industry every year since it was found from the shrimp ponds in the west coast of the South Korea in 1993. Various polyculture technologies of shrimp with shellfish, finfish or seaweeds have been implemented to reduce economic damages by mass mortalities of shrimp. Among them, the polyculture of shrimp with carnivorous fish can suppress or delay the viral outbreak of shrimp ponds because the fish may selectively eat the moribund shrimps infected by virus. To determine the selective predatory effect of river puffer Takifugu obscures on WSSV infected shrimp, postlarvae of Litopenaeus vannamei and Fenneropenaeus chinensis. One-year old river puffers were stocked to four earthen ponds of $1,616-1,848\;m^2$ in surface area as followings: polyculture LvP, L. vannamei ($43.4/m^2$)+puffer ($0.22/m^2$); control Lv, L. vannamei ($46.9/m^2$); polyculture FcP, F. chinensis ($30.3/m^2$)+puffer ($0.25/m^2$); control Fc, F. chinensis ($24.6/m^2$). Ponds of control Fc and polyculture FcP had mass mortalities by WSSV outbreak on the $51^{st}$ and $57^{th}$ days of culture respectively. The shrimps of polyculture LvP and control Lv were harvested on the $95^{th}\;day$. Shrimp survival rates of polyculture LvP and control Lv were 32.4% and 18.2% respectively and shrimp productivity of polyculture LvP was 69.2% higher than that of control Lv. Concentration of nutrients (TAN, $NO_2-N$, $NO_3-N$) was maintained within optimal ranges for shrimp growth although that of polyculture ponds showed at least two times higher than that of control ponds. The results suggest that polyculture of L. vannamei with river puffer is higher than monoculture in survival rate and productivity. In addition, F. chinensis should be carefully cultured because this species shows much higher susceptibility to WSSV than L. vannamei.

• Journal of the Korean Geographical Society
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• v.38 no.4
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• pp.630-639
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• 2003

This study aims to analysis the distribution and change of cropland and forest, the Onseong, Saebyeol, and Eundeok counties on the lower reach of Duman(Tumen) river, northeast Korea, using 1992 year Landsat TM data, 2000 year Landsat ETM data, and digital terrain elevation data(DTED). Land cover and land use of the study areas are classified into cropland, forest, village, and water body, using the supervised classification method including 1:50,000 DTED analysis, image band composition, and principal component analysis(PCA). Results of quantitative analysis present that each growth rate of cropland of Onseong and Eundeok are 22.8% and 14.7% corresponding to decreasing rates of forest, 8% and 13.6% during 8 years from 1992 to 2000. In Onseong, Saebyeol, and Eundeok, each values of mean elevations and slope gradients increased to 192m, 95m, and 91m from 157m, 85m, and 78m, and to 6.6$^{\circ}$, 3.0$^{\circ}$, and 4.4$^{\circ}$ from 5.2$^{\circ}$, 2.5$^{\circ}$, and 3.0$^{\circ}$. Especially, in case of newly developed cropland, the values of mean elevation and mean gradient have 225m, 122m, and 127m, and 9.4$^{\circ}$, 5.1$^{\circ}$, and 8.0$^{\circ}$, in above three regions. These new croplands were developing along to deeper valleys and toward lower hill and mountain slope up to knickpoint zone of gradient change. Deforested lands for cropland have formed irregular pattern of patch-type, and become sources for the sheet erosion, rilling and gulleying in mountain slope and sedimentation in local river channel. Though there were no field checking, analysis using landsat images and GIS mapping can help understand actual environmental problems relating to cropland development of mountain slope in North Korea.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.182-187
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• 2013

In closed plant production system like plant factory, changes in environmental factors should be identified for conducting efficient environmental control as well as predicting energy consumption. Since high relative humidity (RH) is essential for crop production in the plant factory, transpiration is closely related with RH and should be quantified. In this study, four varieties of lettuces (Lactuca sativa L.) were grown in a plant factory, and the leaf areas and transpiration rates of the plants according to DAT (day after transplanting) were measured. The coefficients of the simplified Penman-Monteith equation were calibrated in order to calculate the transpiration rate in the plant factory and the total amount of transpiration during cultivation period was predicted by simulation. The following model was used: $E_d=a*(1-e^{-k*LAI})*RAD_{in}+b*LAI*VPD_d$ (at daytime) and $E_n=b*LAI*VPD_n$ (at nighttime) for estimating transpiration of the lettuce in the plant factory. Leaf area and transpiration rate increased with DAT as exponential growth. Proportional relationship was obtained between leaf area and transpiration rate. Total amounts of transpiration of lettuces grown in plant factory could be obtained by the models with high $r^2$ values. The results indicated the simplified Penman-Monteith equation could be used to predict water requirements as well as heating and cooling loads required in plant factory system.

• Journal of Korean Society of Forest Science
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• v.83 no.3
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• pp.311-321
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• 1994

Experiments were conducted to evaluate the efficacy of ground and foliar sprinkling of natural water for control of the pine needle gall midge, Thecodiplosis japonensis, by disturbing the reproductive behavior of adults such as copulation and oviposition. Diurnal ground spray for whole area application and foliar spray for single tree treatment were tested at day time during the period of adult emergence. The results obtained are as follows : 1. The population density of overwintering larvae in soil was not affected by the water spray during the adult emergence period. 2. Spraying the water showed no effect on the whole period and number of adult emergence, but retarded early emergence and facilitated Late emergence. The difference in the emerging time by 50% emergence day was approximately 7 days. 3. Ground spray was significantly different from control in gall formation rates but was not sufficient for effective control. As a single-tree treatment, the foliar spray was found to be highly effective for control of the pine needle gall midge, Average gall formation of spray plots and untreated ones were 2.6% and 38%, respectively ; control value exceeded 90%. 4. Ground spray of water was not effective in reducing larvae in gall of needle. Foliar spray, however, reduced 45% of larval numbers. 5. Foliar spray accelerated shoot growth by 15%-18%. 6. Foliar spray was highly effective for the control of sucking insects, such as mites and aphids on pine trees.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.64-72
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• 2014

This study quantified the storage and annual uptake of carbon by apple trees in orchards as a production-type greenspace, and computed the annual carbon emissions from apple cultivation. Tree individuals in the study orchards were sampled to include the range of stem diameter sizes. The study measured biomass for each part including the roots of sample trees through a direct harvesting method to compute total carbon storage per tree. Annual carbon uptake per tree was quantified by analyzing the radial growth rates of stem samples at ground level. Annual carbon emissions from management practices such as pruning, mowing, irrigation, fertilization, and use of pesticides and fungicides were estimated based on maintenance data, interviews with managers, and actual measurements. Regression models were developed using stem diameter at ground level (D) as an independent variable to easily estimate storage and annual uptake of the carbon. Storage and annual uptake of carbon per tree increased as D sizes got larger. Apple trees with D sizes of 10 and 15 cm stored 9.1 and 21.0 kg of carbon and annually sequestered 1.0 and 1.6 kg, respectively. Storage and annual uptake of carbon per unit area in study orchards were 3.81 t/ha and 0.42 t/ha/yr, respectively, and annual carbon emissions were 1.30 t/ha/yr. Thus, the carbon emissions were about 3 times greater than the annual carbon uptake. The study identified management practices to reduce the carbon footprint of production-type greenspace, including efficient uses of water, pesticides, fungicides, and fertilizers. It breaks new ground by including measured biomass of roots and a detailed inventory of carbon emissions.