• 환경영향평가
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• 제7권2호
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• pp.5-14
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• 1998

This study was performed to estimate interrelation between characteristics of sediment and nutrient releare from sediment in Dae-cheong lake. For the investigations, sediments were sampled in June and October 1997 at fish farms, embayment, and the main stream of Dae-cheong lake. Items for investigation are as follows; water content, weight loss on ignition(IG), porosity of sediment, Total Kjeldahl Nitrogen(TKN), content of element(H, N, C), nutrient release rate. Water content and porosity were measured to conjecture the physical trait and grain size. And weight loss on ignition was measured to determine the contents of organic substance. For the determination of nutrient release rate, $PO_4-P$ and $NH_4-N$ concentration of interstitial water and overlying water were measured. Release rate of nutrients which has direct influenced upon the water quality were 0.05-8.63mg-$P/m^2{\cdot}day$ and 4.99-36.56mg-$N/m^2{\cdot}day$. And it was found that release rate was measured higher in the 1st sampling than in the 2nd sampling. And for determination of the humus level of sediment, carbon and nitrogen content were measured by using elemental analyzer. Generally, C/N ratio is used to determine humus level of lake sediment. As a result of elemental analysis, C/N ratio was determined in the range of 7.64~11.55, so humus level of Dae-cheong lake sediment was estimated from mesohumic state to oligohumic state.

• 대한환경공학회지
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• 제32권1호
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• pp.1-8
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• 2010

하구형 호수인 아산호(평택호)에서 방조제 근처의 A지점과 상류 하천이 유입되는 B지점을 선정하여, 퇴적물 성상과 퇴적물에서 발생하는 영양염 용출량을 측정함으로써 퇴적물이 아산호 수질에 미치는 영향에 대해 살펴보았다. 아산호의 퇴적물은 sandy loam으로 이루어져있고, 대부분의 인이 Nonapatite-P(64.7%)의 형태로 존재하고 있으므로, 수중의 pH 상승이나 혐기성 상태로의 전환 등에 의해 다량의 인이 퇴적물에서 용출되어 수체의 부영양화에 영향을 줄 수 있는 가능성이 있다. 4월이 6월에 비해 용출율이 높게 나타남을 알 수 있었다. 방조제 근처인 A지점에서는 질소, 유입지천의 합류점인 B지점에서는 인의 용출이 활발히 일어났다. 용출율과 퇴적물의 표면적을 이용해 일일 평균 용출량을 계산해보면, TN는 6,609 kg/d, TP은 3,877 kg/d로 유입지천으로부터 유입되는 TN의 93,616 kg/d 중 7.06%, TP의 17,590 kg/d 중 22.04%에 해당되는 값으로, 아산호의 퇴적물이 저수지 수질에 미칠 영향은 적다고 볼 수 있다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권2호
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• pp.169-179
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• 1998

This paper was performed to estimate interrelations between humus level of sediments and nutrient release from sediments in Dae-cheong reservoir. For investigations, sediments were sampled in June and October, in 1997 at fish farms, embayment, and the main stream of Dae-cheong reservoir. Items for investigation are as follows; water content, weight loss on ignition(IG), porosities of sediments, contents of element such as hydrogen, nitrogen, carbon, and nutrient release rates. Water contents and porosities were measured to conjecture the physical trait and grain size trait. Weight loss on ignition was measured to determine the contents of organic substance. For determination of the humus level of sediments, carbon and nitrogen contents were measured by elemental analyzer. As a result of elemental analysis, C/N ratio was determined in the range of $3.0\~13.1$. From the elemental analysis, humus level of Dae-cheong reservoir sediment was estimated from mesohumic state to oligotrophic state. For the determination of nutrient release rate, $PO_4-P$ and $NH_4-N$ concentrations of interstitial water and overlying water were measured. By using the concentration difference between interstitial water and overlying water and using the Fick's diffusion law, the release rates of phosphorus and nitrogen from the sediment samples were calculated. Release rates of nutrients which directly influence to the water quality were $0.05\~8.63mgP/m^2day$ and $4.99\~36.56mgP/m^2day$. It was found that release rate was measured higher in the 1st sampling period than in the 2nd sampling period. For the determination of phosphorus content in sediment, TPs were measured in 807\~1542{\mu}g/g$ in the 1st samling period and $677\~5238{\mu}g/g$ in the End samling period. Phosphorus release rate and phosphorus content were not interrelated each other.

• 아시안잔디학회지
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• 제21권2호
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• pp.177-182
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• 2007

축구장의 식재지반이 모래로 조성될 경우 낮은 보비력과 높은 용탈율로 인해 시비관리의 조정이 필요하다. 본 실험의 목적은 PVC관을 이용한 경기장 유사모형 실험구에서 캔터키 블루그래스에 있어서 완효성비료의 생육 효과를 비교 실험하였다. 잔디의 색깔, 균일도, 생육, 지상부 생체량과배출수의 질산의 유출량을 몇 가지 다른 생육상과 네 번의 유사 강우 시험 시 행하였다. 실험 결과 요소의 성분 유출량이 가장 높았고 공시 완효성비료는 가장 낮았다. 이 완효성 비료는 다른 공시 잔디비료에 비해 14일간, 요소보다는 28일간 잔디의 품질 면에서 비효가 지속되었다. 또한 이 완효성비료는 잔디의 웃자람과 잔디깎기에 소요되는 시간을 줄일 수 있었다. 질산태 질소의 유출에 있어서도 잔디의 조성 초반기에 50% 정도를 감소 시켰다.

• Journal of Ecology and Environment
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• 제43권4호
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• pp.376-384
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• 2019

Background: Nutrient release during litter decomposition was investigated in Vitex doniana, Terminalia avecinioides, Sarcocephallus latifolius, and Parinari curatellifolius in Makurdi, Benue State Nigeria (January 10 to March 10 and from June 10 to August 10, 2016). Leaf decomposition was measured as loss in mass of litter over time using the decay model W_t/W₀ = e-^{kd t}, while $Kd=-{\frac{1}{t}}In({\frac{Wt}{W0}})$ was used to evaluate decomposition rate. Time taken for half of litter to decompose was measured using T₅₀ = ln ²/k; while nutrient accumulation index was evaluated as $NAI=(\frac{{\omega}t\;Xt}{{\omega}oXo})$. Results: Average mass of litter remaining after exposure ranged from 96.15 g, (V. doniana) to 78.11 g, (S. lafolius) in dry (November to March) and wet (April to October) seasons. Decomposition rate was averagely faster in the wet season (0.0030) than in the dry season (0.0022) with P. curatellifolius (0.0028) and T. avecinioides (0.0039) having the fastest decomposition rates in dry and wet seasons. Mean residence time (days) ranged from 929 to 356, while the time (days) for half the original mass to decompose ranged from 622 to 201 (dry and wet seasons). ANOVA revealed highly significant differences (p < 0.01) in decomposition rates and exposure time (days) and a significant interaction (p < 0.05) between species and exposure time in both seasons. Conclusion: Slow decomposition in the plant leaves implied carbon retention in the ecosystem and slow release of CO₂ back to the atmosphere, while nitrogen was mineralized in both seasons. The plants therefore showed effectiveness in nutrient cycling and support productivity in the ecosystem.

• 한국물환경학회지
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• 제25권5호
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• pp.742-749
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• 2009

To examine the characteristics of the nutrient release from the sediments in two reservoirs, Lake Paldang and Lake Cheungpyeung, we analyzed physical and chemical properties of the sediments and calculated the nutrient release rates from the sediments. The particle properties of sediments in Lake Paldang changed from silt to sand after summer rainy season, especially in the water area of the Kyeungan River where the water depth was shallow and the width of river was narrow. The sediments in Lake Cheungpyeung had higher contents of silt and clay than in Lake Paldang, and the particle size was not much different before and after rainfall. The release rates of nutrients in two lakes varied with the kind of nutrients and the season. The release rates of DTN and ${NH_4}^+-N$ in Lake Paldang were faster in spring than autumn. But the Lake Cheungpyeung showed similar values of release rates before and after summer rainy season. ${NO_3}^--N$ and phosphorous were not released from sediments or were absorbed into sediments all the time in two lakes. Compared with other lakes, the sediments of two lakes consisted of bigger particles and had a lower organic matters content than other lake-type reservoirs. Due to the short hydraulic retention time and no stratification throughout the year in Lake Paldang and Lake Cheungpyeung, the release rates of nutrients from sediment in these reservoirs were lower than other lakes and this seems to be a typical characteristic of river-type reservoirs.

• The Korean Journal of Ecology
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• 제26권6호
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• pp.313-319
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• 2003

Dry weight loss and nutrient release from leaf litter for six tree species were studied using litter bag methods. The litter bags were incubated for f6 months on the forest floor in temperate deciduous forest in Mt. Cheonma, located at the middle part of Korean Peninsula. The changes in nutrient content and the rate of dry weight loss in leaf litter varied with litter types. The litter of Pinus densiflora showed the lowest rate of mass loss (k=0.33), nitrogen concentration (0.89%) and ash concentration (2.50%), while showed the highest C/N ratio (63.40). On the other hand, the litter of Acer pseudo-sieboldianum showed the fastest rate of mass loss (k=0.82), the highest nitrogen concentration (1.11%), and the lowest C/N ratio (49.40). During the decomposition, nitrogen, phosphorus and calcium in the leaf litters showed relatively slow decreasing pattern compared to other elements (carbon, potassium, magnesium, manganese and sodium), but potassium and sodium decreased at early stage of the decomposition for all leaf litters. Differences in annual decomposition rates of litter among species were consistent with the particular chemical characteristics of their leaf litters. The initial concentration of nitrogen was positively correlated with litter decomposition rate for six species, while litter decomposition rate of six species was negatively correlated with C:N ratio of initial leaf litters.

• Journal of Forest and Environmental Science
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• 제26권1호
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• pp.17-23
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• 2010

The present study was conducted to quantify wood and leaf litter decomposition and nutrient release of a dominant tree species, Tectona grandis Linn. F. in a tropical dry deciduous forest of Rajasthan, Western India. The mean relative decomposition rate was maximum in the wet summer and minimum during dry summer. Rainfall and its associated variables exhibited greater control over litter decomposition than temperature. The concentrations of N and P increased in decomposing litter with increasing retrieval days. Mass loss was negatively correlated with N and P concentrations. The monthly weight loss was significantly correlated (P < 0.05) with soil moisture and rainfall in both wood and leaf litter. Tectona grandis was found to be most suitable tree species for plantation programmes in dry tropical regions as it has high litter deposition and decomposition rates and thus it has advantages in degraded soil restoration and sustainable land management.

• Asian-Australasian Journal of Animal Sciences
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• 제19권2호
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• pp.181-188
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• 2006

The objective of this research was to determine the effects of synchronizing the rate of dietary energy and nitrogen release on: ruminal fermentation, microbial protein synthesis, blood urea nitrogen, and nutrient digestibility in beef cattle. Four, two-and-a-half year old Brahman-Thai native crossbred steers were selected for the project. Each steer was fitted with a rumen cannula and proximal duodenal cannula. The steers were then randomly assigned in a $4{\times}4$ Latin square design to receive four dietary treatments. Prior to formulation of the dietary treatments, feed ingredients were analyzed for chemical composition and a nylon bag technique was used to analyze the treatments various ingredients for degradability. The treatments were organized in four levels of a synchrony index (0.39, 0.50, 0.62 and 0.74). The results showed that dry matter digestibility trend to be increased (p<0.06), organic matter and acid detergent fiber digestibility increased linearly (p<0.05), while crude protein and neutral detergent fiber digestibility were not significantly different (p>0.05). Higher concentration and fluctuation of ruminal ammonia and blood urea were observed in the animal that received the lower synchrony index diets. As the levels of the synchrony index increased, the concentrations of ruminal ammonia nitrogen and blood urea nitrogen, at the 4 h post feeding, decreased linearly (p<0.05). Total volatile fatty acid and bacteria populations at the 4 h post feeding increased linearly (p<0.05). Microbial protein synthesis trend to be increase (p<0.08). The results of this research indicate that synchronizing the rate of degradation of dietary energy and nitrogen release improves ruminal fermentation, microbial protein synthesis and feed utilization.

• 한국물환경학회지
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• 제33권6호
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• pp.670-679
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• 2017

An experiment to study the effect of temperature, light, and dredging on release of nutrients downstream from Gongjicheon in the Uiam reservoir was carried out in the laboratory using sediments from different depths. At various water temperatures, dissolved total nitrogen was not released, but the average nutrient flux of dissolved total phosphorus was increased (0.034 at $15^{\circ}C$, 0.005 at $20^{\circ}C$, 0.154 at $25^{\circ}C$, $0.592mg/m^2/d$ at $30^{\circ}C$). Dissolved total phosphorous was released in controlled darkness. In contrast, in controlled light, the concentrations of dissolved total phosphorous and dissolved total nitrogen in the overlying water steadily decreased during the study period (70 d), because they were continuously consumed by the growth of photosynthetic algae. However, there was no significant relationship between water nutrient concentration, nutrient release, and the depth of the sediment. We concluded that the dredging of sediment would not affect the nutrient release rate of the sediment, because there were no significant differences in the nutrient concentrations released from the sediment. When the sediment was removed from the surface to 20 cm in depth, the nutrients were not transferred to the water body, implying that the sediment removal had little effect on secondary pollution.