• Applied Biological Chemistry
• /
• 제25권3호
• /
• pp.150-154
• /
• 1982

중질소요소(重窒素尿素)를 사용(使用) 3품종(品種)에 대(對)한 분시시험(分施試驗)을 폿드에서 수행하였다. 2회분시(回分施)는 4회분시(回分施)보다 통일계(統一系)에 월등히 좋았다. 시비효율(Fe), 이용율(利用率) 및 흡수시비질소효율(吸收施肥窒素效率)(Ef)은 4회분시(回分施)보다 2회분시(回分施)에서 월등히 컸다. Fe의 순위는 Ef의 순위와 같았다. 수량(收量)과 중질소과잉율(重素窒過利率)은 통일계(統一系)가 생육초기(生育初期)에 시용질소(施用窒素)를 많이 흡수(吸收)하여 후기(後期)에 상당히 재전류(再轉流)시킴을 나타내었다. 흡수시비질소(吸收施肥窒素)에 대(對)한 토양질소흡수증가량(土壤窒素吸收增加量) $({\Delta}Ns/Nf)$은 시비(施肥)로 인(因)한 토양질소이용율(土壤窒素利用率)의 지표(指標)가 될 수 있다.

• 한국작물학회지
• /
• 제50권1호
• /
• pp.16-21
• /
• 2005

This study was conducted to establish the elaborate nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy. The nitrogen uptake by rice plants was insignificant until 25 days after seeding, and increased gradually thereafter. During this early growth stage, rice plants absorbed only the $4\%$ of basal applied N, while the $45\%$ of N fertilizer remained in the paddy soil. The absorption of basal N by rice plants was almost completed at 46 days after application. Nitrogen top-dressed at 5-leaf stage was well matched to crop nutrient demand, so it could be absorbed so actively in 8days after application. As a result, we could cut down the amount of N fertilizer to $36\%$ of the basal N level without significant difference in yield. Plant recoveries of fertilizer $^{15}N$ applied with different application timings were $7.8\%$ for basal, $9.4\%$ for 5-leaf stage, $17.1\%$ for tillering stage, and $23.4\%$ for panicle initiation stage, respectively. When urea was applied with nitrogen fertilization practice based on basal incorporation (BN), plant recovery of $^{15}N$ at harvest was $31.0\%$, which was originated from $13.7\%$ for grain, and $21.3\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. Plant recovery of fertilizer $^{15}N$ applied with nitrogen fertilization practice based on topdressing at 5-leaf stage (TN), where N rate was reduced by $18\%$ compared with BN, was $35.1\%$ (grain $15.6\%$), and $19.9\%$ of the fertilizer $^{15}N$ remained in the soil, and the rest could be uncounted. TN showed a higher $^{15}N$ recovery than BN because it was to apply N fertilizer at a time to well meet the demand of rice plant direct-seeded on flooded paddy. We concluded that TN would be the nitrogen fertilization method to enhance N use efficiency in direct-seeded rice on flooded paddy.

• 환경생물
• /
• 제27권3호
• /
• pp.279-284
• /
• 2009

In order to understand food sources-metabolism for the pacific oyster (Crassostrea gigas), the stable isotope ratios of carbon (${\delta}^{13}C$) and nitrogen (${\delta}^{15}N$) of its gut, gill, and muscle as well as potential food sources (particulate organic matter, sedimentary organic matter, benthic microalgae, seagrass detritus) were determined in Dongdae Bay. Average ${\delta}^{13}C$ and ${\delta}^{15}N$ values reflect that oysters primarily fed on sedimentary organic matter as opposed to suspended organic matter during summer and winter seasons. However, the relatively enriched $^{15}N$ values of particulate organic matter (>$250{\mu}m$) and sedimentary organic matter in the summer may be due to the photosynthetic incorporation of $^{15}N$-enriched nitrogen (DIN) or the spawning events of bivalves. Specific oyster tissues (gut, gill, and muscle) revealed different metabolic pathways, which were determined through analysis of ${\delta}^{13}C$ and ${\delta}^{15}N$ in each organ. The present results suggest the determination of carbon and nitrogen stable isotopes to be a useful approach in ecological research related to the food sources- metabolism of Crassostrea gigas.

• Environmental Engineering Research
• /
• 제15권2호
• /
• pp.111-115
• /
• 2010

To study the relationship between the concentrations of nitrogen in mountain streams, and anthropologic and natural factors, the water chemistry of the mountain streams in the entire Hyogo Prefecture, Japan, were investigated. A thousand mountain streams were investigated between 1998 and 2001. The concentrations of nitrate nitrogen ranged from 2.92 to 0.1 mg/L, with an arithmetic mean value of 0.45 mg/L. A number of streams showing more than 1.0 mg/L of nitrate nitrogen accounted for 8% of the mountain streams investigated. These results indicated that the concentrations of nitrate nitrogen in the mountain streams were low in the entire Hyogo Prefecture. In general, the mountain stream water in Hyogo Prefecture appears to not have been affected by wet and dry deposition originating from anthropologic sources in mountain streams and Japan. On the other hand, sites with more than 0.8 mg/L nitrate nitrogen were distributed over the entire Hyogo Prefecture, which were classified into five groups. Each group showed unique geographical, geological and anthropological characteristics. No common characteristic among five groups were discover. These results suggest that the cause of high concentrations of nitrogen in mountain streams is not from a uniform set of conditions.

• 상하수도학회지
• /
• 제27권1호
• /
• pp.77-82
• /
• 2013

The growth and removal capacity of nitrogen and phosphorus of Chlorella vulgaris were evaluated in artificial wastewater with different nitrogen and phosphorus concentrations as element growing components for microalgae growth. The nitrogen concentration was varied in 9, 15, 30 and 60 mg-N/L with fixed phosphorus concentration of 3 mg-P/L. The growth and phosphorus removal capacity of C. vulgaris were high at initial nitrogen concentration of 15 and 30 mg-N/L, and the corresponding N/P ratios calculated were 5 and 10. In the case of varying in 1.5, 3, 6 and 10 mg-P/L of phosphorus concentration with fixed nitrogen concentration of 30 mg-N/L, the growth and removal capacity of nitrogen and phosphorus were excellent with phosphorus concentration of 3 and 6 mg-P/L. The corresponding N/P ratios were shown as 10 and 5. Therefore, the appropriate N/P ratio was concluded between 5 and 10 for wastewater treatment using C. vulgaris.

• KSBB Journal
• /
• 제16권3호
• /
• pp.314-319
• /
• 2001

A nitrifier consortium immobilized in polyvinyl alcohol was used to remove ammonia nitrogen from synthetic wastewater in an airlift bioreactor. The minimum aeration rates were 0.4, 0.6, 0.8 and 1.0 vvm for 5, 10, 15 and 20% immobilized bead packing volume fraction, respectively. The efficient packing fraction and the aeration rate for ammonia nitrogen removal were 15% and 2.4 vvm, respectively. With a hydraulic retention time of 0.5hr, the removal rate and the efficiency of ammonia nitrogen removal were 1685 g/㎥$.$day and 48% at an influent ammonia nitrogen concentration of 75 g/㎥.

• 한국응용곤충학회지
• /
• 제19권4호
• /
• pp.199-202
• /
• 1980

실소시비량 및 재식거리간 벼 흰빛잎마름병 발병과 관계를 조사한 결과는 다음과 같았다. 1. 질소시비량과 발병과는 시비량의 증가에 따라 발병율이 많아지는 경향을 나타냈으며, 7.5kg/10a<15kg/10a<30kg/10a의 순으로 발병이 높았다. 2. 질소시비량이 배비(30kg/10a)일 경우에는 재식거리와는 관계없이 전체적으로 높은 발병율을 나타내었다. 3. 표준시비구(15kg/10a)에서는 $10\times20cm,\;15\times30cm$(표준재식거리)에서 발병도에 큰 차이를 볼 수 없었으나, 재식거리가 넓은 구$(20\times40cm)$에서 발병이 높았다.

• KSBB Journal
• /
• 제11권4호
• /
• pp.497-503
• /
• 1996

본 연구에서는 질소원의 종류와 농도 그리고 pH가 플루란 생산에 미치는 영향을 고찰하였다. A Aureobasidium pullulans에 의한 플루란 생산시 가장 좋은 질소원으로는 수율 62%를 얻은 peptone 이었고, 최적 질소원 농도는 유기질소원의 경우 탄 소원/질소의 비가 50j0.15N이었고 그 이상에서는 저해가 일어났다. 훈합질소원 I, II, III을 사용하 였을 때 각각 29.1, 27.4, 26.5g/L의 플루란 생산량 을 보였다. 그러므로, 혼합 질소원을 잘 이용하면 플 루란을 효과적으로 생산할 수 있었다. pH를 조절하 지 않을 때가 pH를 일정하게 할 때보다는 플루란 수율이 높았다. 또, 유가식배양시 탄소원과 질소원을 함께 공급하였을 때가 질소원만을 공급하였을 때 더 큰 플루란 수율을 보였다.

• 한국작물학회지
• /
• 제51권1호
• /
• pp.32-40
• /
• 2006

The nitrogen (N) absorption and partition of the rice plants are important indicators that can be used to improve the N use efficiency (NUE) of the plants. Improving the plant NUE can help to avoid nutrient waste that may cause environmental pollution. To investigate the N absorption and partition of the rice plants, Hwaseongbyeo (Japonica) and Dasanbyeo (indica/japonica) were applied with N fertilizers at the rates of 60, 120, and 180 kg N per ha in paddy field. Also micro plots of $0.81m^2$ were established inside each plot for application of $^{15}N-labeled$ fertilizer. The differences in N utilization of the rice plants were associated with the total N absorption and partitioning after the heading stage. In the grain filling period, the increase of nitrogen content in the total and leaf blades of Dasanbyeo was higher than that of Hwaseongbyeo. Soil N was the main contributor for the increase of total N of Dasanbyeo during the grain filling period. The N fertilizer uptake rate of Hwaseongbyeo rapidly increased with the increment of N fertilization rate. In Dasanbyeo, N fertilizer uptakes were similar under all rates and times of N application. From heading stage to harvest, Dasanbyeo continued accumulating nitrogen, whereas Hwaseongbyeo had small changes. In conclusion, the difference in nitrogen absorption and partition after heading of the two cultivars was caused by the ability of Dasanbyeo to accumulate and remobilize soil nitrogen to the grains during the grain filling period.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2005년도 추계학술발표회 요지
• /
• pp.192-193
• /
• 2005