• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.343-347
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• 2010

Heavy application of fertilizer and manure in excess from the optimum requirement for crop growth can increase phosphorus (P) accumulation and P release potential in soils. In this study, the relationship between soil test P and 0.01M $CaCl_2$ extractable P was analysed to evaluate the P release potential of agricultural soils under different land-use. The paddy, upland, plastic film house(PFH) soils were sampled from Tongyoung and Changnyeong, and Daegok areas in Gyeongnam province, respectively. With respect to the P accumulation, available P contents in upland and PFH soils were 619 and 796 mg $P_2O_5$/kg, respectively indicating that different land-use types can greatly impact soil P accumulation. As soil available P was increased in the paddy soil, the content of 0.01M $CaCl_2$ extractable P also linearly increased without change point. Comparatively, P threshold were detected at 520 mg $P_2O_5$/kg in both upland and PFH soils, indicating that P release potential were higher in these land-use systems. For reducing P release from agricultural soils, management of optimum P content is needed in soils possessing high P release potential. Further, the change point value, if it is to be used as an environmental indicator, requires more detailed investigation to cover a wide range of soil characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.107-119
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• 2008

To determine the true digestible phosphorus (TDP) requirement of growing pigs, two experiments were designed with the experimental diets containing five true digestible P levels (0.16%, 0.20%, 0.23%, 0.26% and 0.39%) and the ratio of total calcium to true digestible P (TDP) kept at 2:1. In Experiment 1, five barrows (Duroc${\times}$Landrace${\times}$Yorkshire) with an average initial body weight of 27.9 kg were used in a $5{\times}5$ Latin-square design to evaluate the effect of different dietary P levels on the digestibility and output of P and nitrogen. In Experiment 2, sixty healthy growing pigs (Duroc${\times}$Landrace${\times}$Yorkshire) with an average body weight (BW) of 21.4 kg were assigned randomly to one of the five dietary treatments (12 pigs/diet), and were used to determine the true digestible phosphorus (TDP) requirement of growing pigs on the basis of growth performance and serum biochemical indices. The results indicated that the true digestibility of P increased (p<0.05) linearly with increasing dietary TDP level below 0.26%. The true P digestibility was highest (56.6%) when dietary TDP was 0.34%. Expressed as g/kg dry matter intake (DMI), fecal P output increased (p<0.05) linearly with increasing P input. On the basis of g/kg fecal dry matter (DM), fecal P output was lowest for Diet 4 and highest (p<0.05) for Diet 5. The apparent digestibility of crude protein (CP) did not differ (p>0.05) among the five diets, with the average nitrogen output of 12.14 g/d and nitrogen retention of 66% to 74% (p>0.05), which suggested that there was no interaction between dietary P and CP protein levels. During the 28-d experimental period of Experiment 2, the average daily gain (ADG) of pigs was affected by dietary TDP levels as described by Eq. (1): $y=-809,532x^4+788,079x^3-276,250x^2+42,114x-1,759$; ($R^2=0.99$; p<0.01; y = ADG, g/d; x = dietary TDP, %), F/G for pigs by Eq. (2): $y=3,651.1x^4-3,480.4x^3+1,183.8x^2-172.5x+10.9$ ($R^2=0.99$; p<0.01; y = F/G; x = dietary TDP, %), and Total P concentrations in serum by Eq. (3): $y=-3,311.7x^4+3,342.7x^3-1,224.6x^2+195.6x-8.7$ (R2 = 0.99; p<0.01; y = total serum P concentration and x = dietary TDP, %). The highest ADG (782 g/d), the lowest F/G (1.07) and the highest total serum P concentration (3.1 mmol/L) were obtained when dietary TDP level was 0.34%. Collectively, these results indicate that the optimal TDP requirement of growing pigs is 0.34% of the diet at a total Ca to TDP ratio of 2:1.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.149-154
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• 2005

Conventionally used flocculation tanks require large space and high energy requirement for mixing. Static flocculators using gravel bed filter operate at a lower flow rate ($5-10m^3/m^2{\cdot}h$). Further, the cleaning of this system is difficult. A novel high rate static flocculator/filter developed at UTS packed with buoyant media such as polystyrene, polypropylene has been found to operate at higher filtration rates (30-45 $5-10m^3/m^2{\cdot}h$). They can easily be cleaned with minimal energy. Detailed experiments conducted with an artificial kaolin clay solution show that buoyant media is an excellent static flocculator in producing uniform filterable microflocs (12-15 m) even when it is operated at a high rate of 30-40 m/h. Detailed filtration experiments were conducted in a wastewater treatment plant to treat the biologically treated effluent with a floating media of depth of 120 cm. This filter was able to remove majority of phosphorus and remaining solids. It reduced significantly the fecal coliforms and fecal streptoccoci, thus requiring less amount of chlorine for disinfection. The advantage of this system is the low energy and water requirement for cleaning of filter bed. The periodic backwash adopted 30 seconds air and water and 30 seconds water cleaning every 90 minutes filter operation. Thisis equivalent to 1-2% of filtered water production. Mechanical cleaning system on the other hand, requires very low energy requirement (<1% of filtered water production).

• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.95-101
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• 2014

Nonpoint pollution sources from agricultural activities are a major cause of water quality impairment. A nutrient management program utilizes farm practices that maintain efficient crop production systems and control agricultural nonpoint pollution sources. The objectives of present study were to identify appropriate best management practices (BMPs) according to changes of cropping system of main upland crop for reducing AGNPs loadings and to simulate the effects of the application of the several BMPs scenarios in Saemangeum watershed. The selected BMP scenarios were: 1) to convert naked barley and hulled barley to hairy vetch or chinese milk vetch, 2) to convert red pepper to soybean crop, and 3) to combine two scenarios, converting naked barley and hulled barley to hairy vetch or chinese milk vetch + converting red pepper to soybean crop. As a result of BMPs application, the crop requirement of nitrogen and phosphorus for upland crop reduced nitrogen by 41% and phosphorus by 47% in scenario 1, whereas scenario 2 reduced nitrogen by 30% and phosphorus by 23%. Overall, scenario 3 reduced nitrogen by 72% and phosphorus by 70% in agricultural non-point pollution sources associated with chemical fertilizer and livestock manure in Saemangeum watershed.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.3
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• pp.121-133
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• 1975

Soils of the agricultural land derived mostly from volcanic ash in Jeju island may be characterized by relatively high PH, high contents of organic matter and exchangeable bases, and significantly low content of available phosphorus. The PH, organic matter, and available phosphorus of the soils in northern Jeju are 6.1, 12.6%, and 23 ppm, while those of the soils in the southern Jeju are 6.4, 3.7 %, and 76 ppm respectively. Upland soils in Jeju may be classified into 4 groups on the basis of soil fertility: black soil, very dark brown soil, dark brown, and red yellow soil. The organic matter content of black soil, very dark soil and dark brown soil is 15%, 7%, and 3% respectively. The soils of high organic matter content show the high phosphorus absorption coefficient, low content of available phosphorus, and low degree of the base saturation. The soil productivity for barley in the northern Jeju is higher than that in the southern Jeju and the productivity in the western Jeju is higher than that in the eastern part. The productivity for barley is in decreasing order of dark brown soil, very dark brown soil and black soil. Yields of potato and sweet potato in Jeju are higher than in the mainland. Those crops are considered to be tolerant to aluminumtoxicity. The response of sweet potato to nitrogen, phosphorus, and potassium in Jeju soils is lower than that in the mainland, while the response of barley and rape to nitrogen and phosphorus is higher than that in the mainland. The response to fertilizer applied is greater in the northern Jeju than in the southern Jeju. Lime requirement for the Jeju soils calculated on the basis of laboratory tests is so tremendous that single application of lime required might induce adverse effect. Most of the phosphorus applied to the Jeju soils is readily fixed as unavailable form and application of phosphorus in the level of 30 to 40 kg/10a is thought to give little effect.

• Journal of Nutrition and Health
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• v.39 no.5
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• pp.451-459
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• 2006

The purpose of our study was to evaluate an association between milk consumption and bone mineral density (BMD) of female college students in Korea. The dietary data of 1,410 Korean college students living in the vicinity of Seoul area were collected through the Food Frequency Questionnaire. The mean age, height, weight and 8MI of the subjects were 20.4 years, 162.1 cm, 52.7 kg, and $20.0\;kg/m^2$ respectively. The mean intakes of energy, protein, and phosphorus were 2,398.7 kcal, 95.2 g, and 1,302.9 mg respectively, which were above their EER or Recommended Intake (RI), but the mean intake of calcium was 657.8 mg which was below its RI, and 44.0% of the subjects did not meet Estimated Average Requirement (EAR) of calcium. The daily milk consumption was 131.1 g, and the total consumption of milk and dairy product was 228.7 g. Forty five percent of the subjects consumed $50{\sim}200\;g$ of milk or dairy products. After the analysis of their dietary intakes, the subjects were divided into quintiles of total consumption of milk and dairy product, which were considered as major source of dietary calcium. Ninety two subjects from the upper quintile (UQ) and 85 subjects from the lower quintile (LQ) were selected and their bone mineral densities (BMD) of lumbar spine (L1-L4) and the femur were examined by the dual energy X-ray absorptiometry. The BMD $(g/cm^2)$of L1, L2, L3, and average of femur were 1.065, 1.150, 1.187, and 0.988 for the UQ subjects, which were significantly higher than those of the LQ subjects, 1.010, 1.090, 1.146, and 0.942 respectively. Moreover, the T-scores of the UQ were significantly higher than those of the LQ. The prevalence rates of osteopenia classified according to WHO's criterion were 12.0% in the UQ. and 20.0% in the LQ group which showed non significant. Blood levels of calcium, and phosphorus of UQ and LQ group were both within the normal range, and were not significantly different. Our results showed that UQ group presented the better status of bone mineral density and bone health. Therfore our results suggest that continuous consumption of more than one and a half cups of milk per day, which corresponds to the least amount of UQ group's consumption, would affect positively on the bone health of Korean adults.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.2
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• pp.227-232
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• 2013

Phytate is not only an unavailable source of phosphorus (P) for broilers but it also acts as an anti-nutrient, reducing protein and mineral absorption, increasing endogenous losses and reducing broiler performance. The objective of this study was to investigate the anti-nutritional effects of phytate by including high levels of phytase in diets not severely limited in available P. A total of 768 male Arbor Acres broilers were distributed in six treatments of eight replicate pens of 16 birds each consisting of a positive control diet (PC), positive control with 500 FTU/kg phytase, negative control (NC) diet with lower available P and calcium (Ca) levels and the same NC diet with 500, 1,000 or 1,500 FTU/kg phytase. Body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR) and mortality were determined at 21 and 35 d of age while foot ash was determined in four birds per pen at 21 d of age. FI, FCR and foot ash where not affected by the lower mineral diets at 21 d of age nor by the enzyme inclusion but broilers fed lower Ca and available P diets had lower BWG. At 35 d of age no difference was observed between broilers fed the positive or NC diets but broilers fed 500, 1,000 and 1,500 FTU/kg on top of the NC diet had better FCR than broilers fed the positive control diet. When compared to birds fed a diet adequate in P, birds fed the same diet included with 500, 1,000 and 1,500 FTU/kg of phytase in marginally deficient available P and Ca diets had an improvement of performance. These results support the concept that hydrolysing phytate and reducing the anti-nutritional effects of phytate improves bird performance on marginally deficient diets that were not covering the P requirement of birds.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.319-324
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• 2015

An estimation of the requirement of minerals based on growth stage and cropping pattern is very important for greenhouse zucchini. This study was performed at farmer's field which was applied with a fertigation system and a semi-forcing cultivation from Feb. to July in 2014, and nitrogen levels were set up with x0.5, x0.75, x1.0 and x1.5 of the NO3-N-based soil-testing recommendation for zucchini cultivation. Top dressing of nitrogen (basal : top = 4 : 6) and potassium (basal : top = 3 : 7) was applied with an interval of every two weeks from two and six weeks after transplanting, respectively, and phosphorus was totally supplied with basal dressing. The nitrogen uptake was the order of x1.0, x0.75, x1.5 and x0.5, phosphorus, x1.0, x0.75, x0.5 and x1.5, and potassium, x0.75, x1.0, x1.5 and x0.5. From these results, it was suggested that highest mineral uptake could be reached between x0.75 and x1.0 of the NO3-N-based soil-testing recommendation. In conclusion, nutrient management based on the growth stage was proven to be better method for favorable growth and yield of zucchini.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.6
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• pp.657-668
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• 2014

Under Korea's Enforcement Decree of the Framework Act on Environmental Policy amended in 2013, total organic carbon (TOC) is newly added as water quality parameter to assess organic pollution in water and aquatic ecosystem. To meet the TOC requirement and improve quality of effluent discharged into public watershed, it is also necessary to develop standards for TOC in effluent from public sewage treatment works (PSTWs). In this study, we reviewed the characteristics and removal efficiency of TOC in influent and effluent of PSTWs. The study found that phosphorus treatment process removed not only soluble phosphorus but also a portion of TOC remaining after the secondary treatment process. TOC concentration in effluent from PSTWs operated in tandem with industrial wastewater treatment work was higher due to influx of insoluble substances from the industrial wastewater treatment work. In order to lay a foundation for the management of TOC from PSTWs, it is necessary to carry out research on TOC from different perspectives. For example, studies on the generation mechanism of TOC and the impact of TOC on drinking water resources, assessment of effluent qualities through monitoring, and development of measures to control TOC for the preservation of aquatic ecosystem are needed.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.115-123
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• 1999

Sewage has been almost treated by secondary treatment process. Secondary-treated effluent of sewage treatment plant caused the pollution of nearby beach. Nitrogen(N) and Phosphorus(P) in effluent water have caused many problems on estuary, such as red tide, eutrophication and aquatic toxicity. Therefore, the effective nitrogen and phosphorus removal from sewage treatment plants is necessary to prevent those pollution problems. However, little sewage treatment plant in Korea is effectively being operated for the removal of the nutrients. This study is analyzed for the effectiveness of cost when tertiary treatment process and Ocean Outfall are applied for the water quality of Suyong Bay After secondary treatment process, the effluent was discharged from the seabed in the depth of 32m of 4000m offshore. Pollutant concentration is decreased as much as the 180 times after the result of initial dilution, so that environmental protection requirement of Suyong Bay can satisfied. This Ocean Outfall process can save the 2.6~3.5 times as much as the cost of construction and operation for tertiary treatment process running over a 20 year.