• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.291-304
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• 2023

Harmful algal blooms (HABs) have become an increasing concern in terms of human health risks as well as aesthetic impairment due to their toxicity. The reduction of water pollutants, especially nutrients from non-point sources in a reservoir watershed, is fundamental for HABs prevention. We investigated the pollutant removal efficiencies of a constructed wetland to evaluate its feasibility as a method for controlling non-point sources located in the Annaecheon stream within the Daecheong Reservoir watershed. The overall removal efficiencies of pollutants were as follows: BOD 14.3%, COD 17.9%, SS 50.0%, T-N 19.0%, and T-P 35.4%. These results indicate that constructed wetlands are effective in controlling pollutants from non-point sources. The seasonal variation in removal efficiency depended on the specific pollutants. The removal efficiencies of BOD, COD, and T-N were stable throughout the year, except during winter, which might have been influenced by lower microorganism activity. In contrast, T-P showed a consistent removal efficiency even during the winter season, suggesting that the wetland can reduce external phosphorus loading to the reservoir. Regarding the effects of pollutant loadings on removal efficiency, the effluent concentrations of all pollutants were significantly decreased compared to those in the influent in case of middle and high loadings. This demonstrates that constructed wetlands can handle high pollutant loads, including the initial runoff during rainfall, to prevent reservoir eutrophication. Despite the various strengths of wetland water purification, there are limitations as passive treatment. Therefore, more case studies should be conducted to suggest optimum operational conditions for constructed wetlands, taking into consideration reservoir-specific characteristics.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.194-199
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• 2011

This study was conducted to evaluate fertigation effects of pig slurry (PS) and chemical fertilizer (CF) in cucumber by investigating the growth and yield, nutrient content and uptake, nutrient use efficiency, and soil characteristics in greenhouse cultivation. The cropping patterns of cucumber were semi-forcing culture and retarding culture, and the experiment involves four treatments: No fertilizer (NF), $26mg\;L^{-1}$ and $52mg\;L^{-1}$ of N application by slurry composting biofiltration liquefied fertilizer (SCBLF), and $52mg\;L^{-1}$ of N treatment by chemical fertilizer. The difference on the plant height of cucumber between SCBLF and CF treatments was no significant, but fresh weight and dry weight of stem and root were higher in $26mg\;L^{-1}$ SCBLF treatment. The Ca content of the leaf was lower in the treatments of SCBLF and the K content of the root was lower in the $52mg\;L^{-1}$ CF treatment. The Ca content of the stem was lowest in the $52mg\;L^{-1}$ CF treatment and the mineral content of the fruit showed no significant difference. In case of semi-forcing culture, the gross yield was lower in the $52mg\;L^{-1}$ CF treatment and the yield of unmarketable fruit was lower in the SCBLF treatments. The nutrient use efficiency of cucumber is as follows: K (8.3 ~ 30.9%), N (4.2 ~ 13.0%), P (1.9 ~ 2.0%). The SCBLF treatments showed higher figure in the soil pH than that of the CF treatment, while EC and the content of $NO_3$-N were higher in the CF treatment than the former. The content of exchangeable K was higher in the plot treated with $52mg\;L^{-1}$ SCBLF, and there were no significant differences in the content of Ca and Mg between the treatments. In conclusion, it is suggested that the application of liquefied manure made from pig slurry may be able to replace the use of chemical fertilizer in nitrogen and potassium.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.180-187
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• 2022

In order to select suitable light in a plant factory, electric energy use efficiency and light use efficiency should be considered simultaneously to consider operating costs as well as quantitative and functional aspects. The growth characteristics, electric energy use efficiency, light use efficiency by light intensity, LED ratio, and photoperiod conditions were compared together. Light intensity is 60, 130, 230, and 320 µmol·m^-2·s^-1 treatments, and light quality is the mixing ratio of red light and blue light 8:2, 6:4, 4:6, and 2:8 treatments. Photoperiod is 9, 12, 15, and 18 hours treatments based on the daytime. In the light intensity experiment, the growth rate increased as the light intensity increased, but there was no significant difference in the light use efficiency. When comparing the leaf fresh weight per power consumption, only the 320 µmol·m^-2·s^-1 treatment group showed significantly low efficiency, and there was no significant difference in the other treatments, so 230 µmol·m^-2·s^-1, which produced the most, was the most efficient. In the light quality experiment, the ratio of red light and blue light was measured to be high at the same time as the growth rate and light use efficiency in RB 8:2, and there was no significant difference in color difference and flavonoids content, so a Red:Blue ratio of 8:2 was the most suitable condition. In the photoperiod experiment, the longer the photoperiod, the higher the growth rate. However, there was no significant difference in the growth rate over 12 hours of daytime, so 12 hours considering the light consumption efficiency was a suitable condition. Based on the above results, LED light environmental conditions for perilla growth in plant factories were light intensity, light quality, and day length of 230 µmol·m^-2·s^-1 or more, 8:2, and 12 hours or more, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.407-414
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• 2016

This study was conducted to investigate the effects of supplementation of dietary betaine on nutrient digestibility and physiological responses in finishing pigs. A total of twelve pigs with a body weight of $80.1{\pm}3.7kg$ were individually caged, and randomly assigned to one of the two experimental diets containing 0 (control) or 5 g/kg (treatment) of the betaine in a $2{\times}2$ Latin square design. The experimental period was 14 days-7 days adaptation and 7 days trial period-per phase. All data for the difference between control and treatment groups were statistically analyzed by student's t-test. Dry matter and crude protein digestibility in the treatment group were significantly improved by 1% and 1.3%, respectively, as compared with those in the control (p<0.05). The apparent absorption of dietary energy was increased from 82.3% to 83.7% by dietary betaine supplementation. Thus, the retention of energy was also significantly increased to above 6% in the treatment group compared with the control group (control 4,057 vs treatment 4,314 kcal; p<0.01). The physiological parameters indicating serum biochemical contents and stress-, immune-, and inflammatory- responses were not changed by the supplementation of dietary betaine. In conclusion, dietary betaine improves the nutrient digestibility without any negative effects in terms of physiology in finishing pigs. It suggests that the supplementation of dietary betaine may increase the productivity through the improvement of weight gain and feeding efficiency.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.4
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• pp.458-465
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• 2010

To investigate the growth and nutrient uptake response of sorghum${\times}$sudangrass ($S{\times}S$) hybrid to different rate of livestock manure compost, a field experiment was conducted in the experimental grassland of Chonnam National University. Six treatments were laid out in a randomized block design with triplicates; control (no input), synthetic fertilizer (20 g N $m^{-2}$ and 20 g $P_2O_5\;m^{-2}$), compost 1 (3.4 g N $m^{-2}$ and 3.6 g $P_2O_5\;m^{-2}$), compost 2 (6.8 g N $m^{-2}$ and 7.2 g $P_2O_5\;m^{-2}$), compost 4 (13.4 g N $m^{-2}$ and 14.4 g $P_2O_5\;m^{-2}$), and compost 6 (20.2 g N $m^{-2}$ and 21.6 g $P_2O_5\;m^{-2}$). Ninety days after treatment, above-ground parts of the plants were harvested and measured for dry matter yield (DMY) and amounts of nutrients (N and P) uptake. Synthetic fertilizer application achieved the greatest DMY (2.4 kg $m^{-2}$) and nutrient uptake (38.3 g N $m^{-2}$ and 15.3 g $P_2O_5\;m^{-2}$). Increasing compost application rate tended to enhance DMY accumulation and nutrient uptake (P<0.01), but DMYs of compost 4 (1.9 kg $m^{-2}$) and 6 (1.8 kg $m^{-2}$) treatments were not different. Therefore, it was suggested that application compost alone may not achieve DMY of $S{\times}S$ hybrid compatible to synthetic fertilizer application. As nutrient uptake efficiency data showed that availability of compost P could be better than SF, it might be a strategy to apply compost as P source with supplementary N application such as liquid manure, SF or green manure if necessary considering availability of N input and the yield goals.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.829-846
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• 2015

This study was conducted to determine the effects of organic fertilization rates on the nutrient accumulation and recovery in radish (Raphanus sativus L.) as well as growth and yield of radish in Jeju island. An understanding the relationships between organic fertilization rate, crop nutrient recovery and crop yield can assist in making organic fertilizer recommendation which balances crop value and environmental risk in organic cultivation. Nitrogen (T-N), phosphate ($P_2O_5$) and potassium ($K_2O$) were applied at 0, 115-35-40, 230-70-80 (standard application rate), 460-140-160, 230-200-100 (recommended application rate) and 158-53-35 kg/ha (customary application rate), respectively as the broadcast application of mixed organic fertilizer (N 4.5% - $P_2O_5$ 1.5% - $K_2O$ 1%) in combination with langbeinite ($K_2O$ 22%), 100% at sowing period. The organic fertilizer was made of organic materials like oil cakes. Total yield of radish, as fresh weight of roots, increased with increasing organic fertilizer doses to a maximum at rate of standard or soil-testing application. Nitrogen, phosphate and potassium accumulations of radish increased curvilinearly with increasing organic fertilization rate to a maximum at rate of N 460 - $P_2O_5$ 140 - $K_2O$ 160 kg/ha. However, nitrogen, phosphate and potassium use efficiency of applied organic fertilizer decreased curvilinearly or linearly with increasing organic fertilization rate. Application of organic fertilizer in combination with langbeinite (as a potassium source) had significant effect on the yield of radish. Organic fertilization on a basis of standard or soil-testing application rate is recommended for maximun radish yield in organic cultivation.

• Food Science of Animal Resources
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• v.27 no.3
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• pp.284-289
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• 2007

This study was conducted to investigate the effects of copper and zinc supplementation on growth performance, nutrient digestibility, and meat and carcass characteristics in finishing pigs. A total of 72 $(Landrace{\times}Yorkshire{\times}Duroc)$ pigs (58.47 kg initial BW) were assigned to 6 treatments in a $2{\times}3$ factorial design $(Zn\;levels{\times}Cu\;levels)$. The sources of zinc and copper were Zn-methionine chelate and Cu-methionine chelate, respectively. Zinc levels used were 80 and 120 ppm and copper levels used were 10, 30 and 60 ppm. Throughout the entire experimental period, the average daily gain (ADG) and average daily feed intake (ADFI) were not significantly affected by Cu or Zn levels, or their relative levels. The G:F ratio was significantly affected by the relative levels of Cu and Zn (p<0.05), specifically at 30 ppm Cu and 120 ppm Zn. Dry matter digestibility was significantly affected by the levels of Cu (p<0.02), Zn (p<0.01) and the relative levels of each (p<0.04), in particular at 30 ppm Cu and 120 ppm Zn. Nitrogen digestibility was significantly affected by Zn levels (p<0.01) and the combination of 30 ppm Cu and 120 ppm Zn (p<0.03). The $L^*-value$, shear force, cooking loss and pH were not significantly affected by Cu levels, Zn levels or their combination. The $a^*- (p<0.04)\;and\;b^*- values (p<0.01)$ were significantly affected by Zn levels at 80 ppm. The Water hoding capacity was significantly affected by Cu and Zn in combination (p<0.01) at 10 ppm Cu and 120ppm Zn. The carcass weight, backfat thickness and carcass grade were not significantly affected by Cu levels, Zn levels or their relative levels. The carcass percentage was significantly affected by the combination (p<0.04) of 30ppm Cu and 120ppm Zn. In conclusion, dietary supplementation of Cu and Zn at 30 and 120 ppm, respectively, is effective for feed efficiency, nutrient digestibility and carcass percentage, while at the levels of Cu at 10 ppm and Zn at 120 ppm have effects on WHC.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.2
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• pp.252-261
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• 2006

Four experiments were conducted to investigate the effect of organic or inorganic acid supplementation on the growth performance, nutrient digestibility, intestinal measurements and white blood cell counts of weanling pigs. In growth trial (Exp I), a total of 100 crossbred pigs ({$Landrace{\times}Yorkshire$}${\times}$Duroc), weaned at $23{\pm}2$ days of age and $7.25{\pm}0.10kg$ average initial body weight (BW), were allotted to 5 treatments by body weight and sex in a randomized complete block (RCB) design. Three different organic acids (fumaric [FUA], formic [FOA] or lactic acid [LAA]) and one inorganic acid (hydrochloric acid [SHA]) were supplemented to each treatment diet. Each treatment had 5 replicates with 4 pigs per pen. During 0-3 wk, average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency (G/F ratio) were not significantly different among treatments. However, pigs fed LAA or SHA diet showed improved ADG by 15 or 13% respectively and 12% greater ADFI in both treatments compared to CON diets. Moreover, compared to organic acid treatments, better ADG (p = 0.07) and ADFI (p = 0.09) were observed in SHA diet compared to pigs that were fed the diet containing organic acids (FUA, FOA or LAA). However, during 4-5 wk, no differences in ADG, ADFI and G/F ratio were observed among treatments. Overall, ADG, ADFI and G/F ratio were not affected by acidifier supplementation. Although it showed no significant difference, pigs fed LAA or SHA diets showed numerically higher ADG and ADFI than pigs fed other treatments. In metabolic trial (Exp II), 15 pigs were used to evaluate the effect of acidifier supplementation on nutrient digestibility. The digestibility of dry matter (DM), crude protein (CP), crude fat (CF), crude ash (CA), calcium (Ca) and phosphorus (P) was not improved by acidifier supplementation. Although the amount of fecal-N excretion was not different among treatments, that of urinary-N excretion was reduced in acidsupplemented treatments compared to CON group (p = 0.12). Subsequently, N retention was improved in acid-supplemented groups (p = 0.17). In anatomical trial (Exp III), the pH and $Cl^-$ concentrations of digesta in gastrointestinal (GI) tracts were not affected by acidifier supplementation. No detrimental effect of intestinal and lingual (taste bud) morphology was observed by acidifier supplementation particularly in inorganic acid treatment. In white blood cell assay (Exp IV), 45 pigs were used for measuring white blood cell (WBC) counts. In all pigs after LPS injection, WBC counts had slightly declined at 2 h and kept elevating at 8 h, then returned to baseline by 24 h after injection of lipopolysaccharide (LPS). However, overall WBC counts were not affected by acidifier supplementation. In conclusion, there was no difference between organic and inorganic acidifier supplementation in weanling pigs' diet, however inorganic acidifier might have a beneficial effect on growth performance and N utilization with lower supplementation levels. Furthermore, inorganic acidifier had no negative effect on intestinal measurements and white blood cell counts in weanling pigs. These results suggested that inorganic acidifier might be a good alternative to organic acidifiers in weanling pigs.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.2
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• pp.31-40
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• 2019

In Korea, 51,013 thousand tons of livestock manure was generated in 2018. A total of 46,530 thousand tons, which is 91.2% of the total amount of livestock manure generated, was treated by composting(40,647 thousand tons) or liquid fertilization(5,884 thousand tons) method. At present, the policy of livestock manure treatment in Korea is to make livestock manure into organic fertilizer(compost, liquid fertilizer) and then to applicate it on agricultural land. And this policy is very effective in terms of livestock manure treatment and nutrient recycling. However, considering the steadily declining farmland area for decades, the use of livestock manure compost could be limited in the future. There is also concern that local nutrient overloading, nutrient management regulation, and restrictions on the number of livestock may become serious problem for livestock manure treatment. In addition, there are some opinions that nutrient derived from livestock manure may flow into tributaries of major dams. In recent years, there has been a suspicion that fine dust may be generated from livestock manure compost. In recent years, the use of livestock manure fertilizer has been rapidly increasing, there is a growing demand of the development of new technologies for livestock manure treatment. Especially, cow excretes a larger amount of manure than other livestock, so that the efficiency of development of new technology for cow manure treatment will be high. Therefore, in this study, the combustion characteristics of cow manure pellet were investigated in order to analyzed whether cow manure could be used as source of solid fuel. During the combustion test, the weight loss of the cow manure pellet began to increase when the temperature of the combustion chamber reached $300^{\circ}C$. The ratio of $H_2$, $CH_4$, CO in the pyrolysis gas produced in the pyrolysis process of cow manure pellet were 6.65~11.62%, 0.58~1.54 and 11.47~14.07%, respectively.

• Journal of Environmental Impact Assessment
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• v.28 no.6
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• pp.549-555
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• 2019

The purpose of this study is to ensure optimal operating conditions for improving the removal efficiency of phosphorus (P) and nitrogen (N) that are the causative agents of eutrophication by utilizing functional media. The main ingredients of the functional media used in this study are Si, Al, and Fe, SiO₂, KAlSiO₃O₈, Al₂O₂·2SiO₂O, H₃Al₂Si₂O₉, Fe₃O₄O), and berylite. To identify the maximum efficiency of the filtration process, the processing efficiency experiment was carried out according to flow method, velocity, and thickness of residual media. The flow method carried out two experiments, 50 m/day, 100 m/day, 150 m/day, 200 m/day, 250 m/day, and 20 cm, 40 cm, 50 cm, 60 cm, 80 cm of lead depth. Experiments have shown that SS, T-N, and T-P all showed higher elimination efficiency of the upflow current conditions than the downflow current conditions, and that the processing efficiency of the linearity is the highest at SS 50 m/day, T-N 150 m/day and T-P 100 m/day. In addition, the analysis of the removal efficiency according to the residual thickness showed that SS, T-N, and T-P all showed the highest efficiency at 60 cm. In addition, the analysis of the removal efficiency according to the residual thickness showed that SS, T-N, and T-P all showed the highest efficiency at 60 cm. It is considered desirable to set the top-down flow conditions and residual thickness of 60 cm and adjust the velocity of the line according to the target media for removal.