• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.4
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• pp.253-258
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• 2001

This pot experiment was conducted to find out the forage productivity and quality in a grasslclover sward as affected by the application of three different fertilizers; double superphosphate(DS), fused Mg-phosphate (FP), and complex fertilizer(CF) on newly reclaimed hilly soil. This part was concerned with the mutual balances of mineral nutrients in the soils and mixed grass/clover sward in relation to grass tetany hazard. The results obtained are summarized as follows : 1. Concentration of exchangeable Mg and relative proportion of Mg to CEC in the soils before experiment were considerably below the critical level for good forage growth and prevention of grass tetany. It seems that these properties would be able to handicap by liming and NPK applications. 2. Comparing with the critical level for likelihood of tetany(Mg <0.2%, K >2.5%, and W(Ca+Mg) >2.2 in forages), mean concentration of Mg ranged from 0.14 in DS plot and 0.18 in FP plot to 0.24% in CF plot. Meanwhile, hazards of grass tetany in relation to the %K and ratio of K/(Ca+Mg) were not recognized. 3. Comparing with the optimum level of Carp(% ratio)=2.0 in forages for animal health, these ranged from 6.1 to 7.1. (Key words : Grass tetany, Fertilizer. Soil. Mineral nutrients)

• ALGAE
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• v.23 no.4
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• pp.277-288
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• 2008

The relationship between nutrients and phytoplankton dynamics was investigated daily from 12 April to 22 July 2003 in Sagami Bay, Japan. According to multidimensional scaling (MDS) and cluster analysis, phytoplankton community was divided into four distinct groups. The first group was consisted of centric diatom species, such as Guinardia spp., Detonula spp., Letocylindrus danicus, Skeletonema costatum, Eucampia zodiacus and Chaetoceros spp.. The second and third clusters comprised mainly diatoms and dinoflagellates, respectively. The other cluster was restricted to the samples collected during the last sampling period when the rainfall and river discharge was frequently recorded. Canonical correspondence analysis (CCA) was applied to analyze four groups respectively, which focused on the effects of nutrients concentration and ratio on phytoplankton variations. Based on CCA analysis, most species of centric diatom were negatively correlated with DSi concentrations and Si/N ratio. Nutrients were strongly limited phytoplankton growth during the summer when the rainfall was not observed, whereas river discharge by rainfall and counterclockwise coastal currents (although the surface circulation pattern is often altered by Kuroshio Current, the counterclockwise coastal currents are generally dominant) has brought phytoplankton population accumulation and triggered the micoalgae growth in western part of the bay. Phosphorous (P) was strongly limited after significantly increases in the phytoplankton abundances. However, silicate (Si) was not a major limiting factor for phytoplankton production, since Si/DIN and Si/P ratio did not create any potential stoichiometric limitation. This indicates that high Si availability contributes favorably to the maintenance of diatom ecosystems in Sagami Bay.

• Animal Bioscience
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• v.34 no.4
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• pp.613-620
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• 2021

Objective: This study aimed at studying the potential use of Flemingia (Flemingia macrophylla) as a protein source fodder to improve nutrients digestibility and ruminal fermentation efficiency in beef cattle. Methods: Four, Thai native beef cattle were randomly assigned in a 4×4 Latin square design. Four levels of Flemingia hay meal (FHM) were used to replace soybean meal (SBM) in the concentrate mixtures in four dietary treatments replacing levels at 0%, 30%, 60%, and 100% of SBM. Results: The experimental findings revealed that replacements did not effect on intake of rice straw, concentrate and total dry matter (DM) intake (p>0.05). However, the apparent digestibilities of DM, organic matter, crude protein, acid detergent fiber, and neutral detergent fiber were linearly increased up to 100% replacement levels. Moreover, the production of total volatile fatty acids, and propionate concentration were enhanced (p<0.05) whereas the concentration of acetate was reduced in all replacement groups. Consequently, the CH4 production was significantly lower when increasing levels of FHM for SBM (p<0.05). Furthermore, rumen bacterial population was additionally increased (p<0.05) while protozoal population was clearly decreased (p<0.05) in all replacement groups up to 100%. In addition, microbial nitrogen supply and efficiency of microbial nitrogen synthesis were enhanced (p<0.05), as affected by FHM replacements. Conclusion: The findings under this experiment suggest that 100% FHM replacement in concentrate mixture enhanced rumen fermentation efficiency, nutrients digestibilities, bacterial population, microbial protein synthesis, and subsequently reduced CH4 production in beef cattle fed on rice straw.

• Journal of the korean society of oceanography
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• v.37 no.2
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• pp.66-75
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• 2002

Temporal variation of nutrients and dissolved major and trace elements have been studied in the Yeongsan River, Korea. There were significant temporal fluctuations in the concentrations of these elements depending upon the flow condition. $NH_4$, $PO_4$, Na, Mg, Ca, K, Mn, Cu, Ni, Zn, Co, As and U concentrations were inversely related to the flow; that is, they are the highest at low flow and the lowest at high flow. It indicates that these elements are derived from point sources such as rock weathering and/or human activities and then diluted by increasing flow. Meanwhile, Fe and Si concentrations varied proportionally to the flow indicating that they are derived from diffuse sources including reactions within soil. The concentration-flow relationships showed that hydrology of the river is the most important factor controlling the chemical composition of the Yeongsan riverwater, which was compatible of the results of R-mode factor analysis.

• Journal of Environmental Science International
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• v.11 no.6
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• pp.519-528
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• 2002

This study was to evaluate the impact of river runoff and salt intrusion by tide on nutrient balance of estuary during a complete tidal cycle. 24 hours time series survey was carried out during a spring tide July 2001 on a tidal estuary in the Keum river. Three stations(A,B,C) were set along a transect line of about 10km, which linked the lower part of estuary dyke to the subtidal zone. Surface water was sampled simultaneously at each station every hours f3r the determination of nutrients. Water temperature, pH and dissolved oxygen were measured in situ. Riverine input of silicate and nitrate during ebb tide significantly increased the concentration of all stations. Conversely, during high tide, nutrient concentration were lowered by the mixing of fresh water with sea water Ammonium nitrogen concentration were higher at intertidal zone(Stn.B) due to sewage inflow to Kyeongpo stream and ammonium release under anaerobic conditions. Also, these results was discussed as a biological component that influences the processes of nutrient regeneration within the estuary. Best correlations were found at lower part of estuary dyke(Stn.A) for salinity against DIN(Y=0.121 Sal.+4.97, r2=0.956) and silicate(Y=0.040 Sal.+2.62, r2=0.785). But no significant correlation was found between salinity and ammonium. Unbalanced elemental ratio(N/P, Si/N and Si/P) depended significantly on the import of nutrients (silicate & nitrate nitrogen) from river and stream. The effect of the tidal cycle and river runoff is important that in determining the extend of the variations in nutrient concentrations at all station.

• Journal of Forest and Environmental Science
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• v.30 no.2
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• pp.208-217
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• 2014

Leaf litter is the main and quick source of organic matter and nutrient to the soil compared to other parts of litter. This study focused on the nutrients (N, P and K) leaching from leaf litter of Melia azadirachta, Azadirachta indica, Eucalyptus camaldulensis, Swietenia macrophylla, Mangifera indica, Zizyphus jujuba, Litchi chinensis, Albizia saman, Artocarpus heterophyllus, Acacia auriculiformis, Dalbergia sissoo and Khaya anthotheca as the common cropland agroforest tree species of Bangladesh. About (9 to 35) % of initial mass was lost, while Electric Conductivity (EC) and TDS (Total Dissolved Solid) of leaching water increased to (573 to 3,247) ${\mu}S/cm$ and (401 to 2,307) mg/l respectively after 192 hours of leaching process. Mass loss (%) of leaf litter, EC and TDS of leaching water showed significant (ANOVA, p<0.05) curvilinear relationship with leaching time. Initial concentration of NH4, PO4 and K in leaching water was found to increase significantly (p<0.05) up to 48/72 hours and then remained almost constant at later stages (48/72 to 192 hours). Mass loss of leaves; EC, TDS, $NH_4$, $PO_4$ and K in leaching water was varied also significantly (ANOVA, p<0.05) among the studied tree species. All the tree species showed similar pattern of nutrients (K>N>P) release during the leaching process. The highest $NH_4$ (4,097 ppm) and potassium (8,904 ppm) concentration was found for M. azadirachta while the highest $PO_4$ (1,331 ppm) concentration was found for E. camaldulensis in the leaching water. Among the studied tree species, M. azadirachta, A. indica, D. sissoo, E. camaldulensis and Z. jujuba was selected as the best tree species with respect to nutrient leaching.

• Journal of Environmental Science International
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• v.29 no.8
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• pp.857-870
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• 2020

In this study, the antibiotic components in the final effluent from the 12 wastewater treatment facilities located in the Nakdong River basin were investigated, and the correlation between organic matters, nutrients and antibiotics was analyzed. In the final effluent of the wastewater treatment facilities, three sulfonamides antibiotics (sulfamethazine, sulfathiazole, sulfachlorpyridazine) and tetracyclines antibiotics (oxytetracycline, doxycycline) were detected. Sulfamethazine were detected at all points and ranged from 10.398 to 278.784 ng/L. Sulfathiazole were detected at 6 points (Andong, Gumi, Hapcheon, Miryang, Uiryeong, Haman), and ranged from 23.773 to 144.468 ng/L. The correlation coefficients between sulfathiazole and TSS, COD, TOC, NH₃-N, NO₂-N, and T-N components were high in the range of 0.73 to 0.92. The correlation coefficient between sulfamethazine and T-N was 0.48, and the correlation with the rest of the water quality components was low. The correlation coefficient between sulfamethazine and sulfathiazole was 0.78. Through this study, it was confirmed that the concentration of sulfonamides antibiotics was higher than the concentration of tetracyclines antibiotics in the final effluent of 12 wastewater treatment facilities in the Nakdong River basin, and the concentration of sulfathiazole increased with organic matters and nutrients.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.943-951
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• 2006

Spatial distribution of water pollution in the Gap Stream was investigated from October to November, 2005. Sampling was conducted three times including effluents discharged from a wastewater treatment plant (WWTP) and a dam reservoir during the low-flow period. As a typical urban stream, total nitrogen and inorganic nitrogen concentrations increased toward downstream. Ammonia concentration was the highest in the treated water of the wastewater treatment plant and the lowest nitrate concentration was found in the effluent of the dam reservoir. A part of soluble reactive phosphorous (SRP) in total phosphorous was 22~54% in the upstream reach of WWTP in the Gap Stream whereas 68~73% in the downstream reach. Mean chlorophyll-a concentration ranged from 1.6 to $11.0{\mu}g/L$ and it tends to increase toward downstream except for WWTP effluent. As expected, untreated wastewater and WWTP effluent were suggested as the major sources of water pollution in the Gap Stream. In this study, the water pollution of the Gap Stream is a significant undergoing typical eutrophication, caused by excessive phosphorus and nitrogen nutrients from WWTP located in the watershed. As a result, the critical factor for the water pollution was evaluated to dissolved inorganic nitrogen and phosphorus nutrients. Particularly, SRP is a most important for the eutrophication. It suggest that may occur in the most urban streams of Korean peninsula. Therefore, because the necessity of water pollution management in the urban stream, inorganic N and P nutrients should be included as an essential component of water quality criteria in the advanced water quality project of Korean Government by enforcing of water quality assessment and total maximum daily loads (TMDLs).

• Ocean and Polar Research
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• v.33 no.1
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• pp.13-20
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• 2011

Comprehensive data collection was carried out between 2001-2006 to investigate the concentration levels of chlorophyll-a, nutrients (DIN and DIP), and COD for surface waters of Korean coastal areas. A statistical analysis of these parameters was carried out on the basis of the frequency distribution of their concentration. Furthermore, the numeric grading for chlorophyll-a, DIN, DIP, and COD concentrations were derived statistically from the normalized frequency distribution of log-transformed data. The statistical grading clearly reflects the water quality characteristics of three Korean coastal water bodies (Western, Southern and Eastern coastal zones), which indicate common environmental and ecological characteristics. So, this study could provide useful information to set up the guideline for water quality assessment of Korean coasts.

• Korean Journal of Organic Agriculture
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• v.21 no.1
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• pp.61-68
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• 2013

This study was conducted to evaluate overwintering of hairy vetch (Vicia villosa Roth), biomass, and inorganic N concentration in soil to verify the adaptability of eight cultivars of hairy vetch into country. Winter survival rate was higher for the hairy vetch cultivars, such as Hungvillosa or Ostsaat, than those of Minnie, Oregon common, and TTF1, which affected amount of biomass of each hairy vetch, with higher biomass observed in Hungvillosa or Ostsaat cultivar. There were no significant difference for the mineral nutrients of each hairy vetch cultivar. Inorganic N concentration in soil was increased at 10 days after mowing by application of Hungvillosa and Ostsaat cultivars that had highly produced N content from the raw materials.