• Applied Biological Chemistry
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• v.25 no.3
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• pp.150-154
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• 1982

Top-dressing pot experiment with $^{15}N$ urea was carried out by using three varieties. Two-split application was much better for Tongil line than 4-split. Fertilization efficiency (Fe), use efficiency (Eu) and absorbed fertilizer nitrogen efficiency (Ef) were much greater in 2-split than in 4-split. The order of Fe followed that of Ef. Grain yield and $^{15}N$ excess % among plant parts suggest that Tonsil line uptakes fertilizer nitrogen much in early stage and retranslocated well later. The order of soil nitrogen increment in plant per fertilizer nitrogen in plant $({\Delta}Ns/Nf)$ might be an index of soil nitrogen use efficiency due to fertilizer.

• Korean Journal of Soil Science and Fertilizer
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• v.2 no.1
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• pp.45-48
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• 1969

In an effort to determine the effect of the physiological function of phosphorus in higher plants, soybean have been used as samples in an attempt to compare them with rice on which there have been a number of reports of research. The absorptive and metabolic process phosphorus in each separate manuring period has been studied. It has iefluenced enhancement of vitality in the plants whether manuring is conducted earlier or later. These phenomena have greatly concerned with the absorption and transference of phosphorus in the process of growth are done more slowly than those of nitrogen and phosphorus from stems and leaves to pods.

• Asian Journal of Turfgrass Science
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• v.5 no.1
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• pp.41-45
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• 1991

서양잔디중 난지형 잔디에 속하는 세인트 어거스틴그래스에서 암모늄태 질소와 질산태 질소질 비료의 시비가 브라운팻치 병 발생에 미치는 영향을 알아보고자 본 실험이 수행되었다. 포장에서 재배되고 있는 세인트 어거스틴그래스를 작경 10cm의 플러그를 굴취하여 플라스틱 포트에 이식한 후 뿌리의 활착을 위하여 온실내에서 한달간 재배하였고, 50kg N/ha의 성분비율에 맞추어서 균의 접종 1일전에 시비를 하였다. 잔디포장에서 분리한 Rhizoctonia solani균을 agar위에서 배양시킨 후 균이 배양되어 있는 agar block 을 떼어서 태운 perennial ryegrass에 접종시켰다. 감염된 perennial ryegrass를 다시금 세인트 어거스틴그래스위에다 치상시켜서 잔디로의 접종을 꾀하였다. 그 결과 암모늄태 질소비료나 질산태 질소비료 그리고 무시비상태의 잔디에서의 병발생간에는 유의차가 인정되지 않았으나 질산화 억제제를 처리하여 암모늄상태의 질소 성분이 질산태로 전환되는 것을 억제시킨 구에서는 타처리구에 비하여 6~9배의 발생율을 보였다. 따라서 잔디의 시비와 병발생을 연관시켜 볼 때 암모늄태 질소비료 와 질산태 질소비료 공히 큰 차이는 없으나, 다만 질산태로 변한 후의 질소양분의 토양용탈로 인한 소모를 억제시키기 위하여 사용되는 질산화 억제제는 상당량의 암모늄태 질소성분을 상당 기간동안 유지시키기 때문에 브라운팻치 병발생에 영향을 주므로 그 사용시기에 있어서 신중을 기하여야 하겠다.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.749-759
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• 2012

A field experiment was conducted to selection of ground-based remote sensor and reflectance indices to estimate rice production, estimation of suitable season for ground-based remote sensor and N top dressing fertilizer application rate in 2010. Fertilizer application was determined by "Fertilizer management standard for crops" (National Academy of Agricultural Science, 2006). Four levels of N-fertilizer were applied as 0%, 70%, 100% and 130% by base N-fertilizer application and were fertilized as 70% of basal dressing and 30% as top dressing. Rice (Oryza sativa L.) of Chucheong and Joonam (Korean cultivar) were planted on May 22, 2010 in sandy loam soil and harvested on October 6, 2010. Reflectance indices were measured 7 times from July 5 to August 23 by Crop circle-amber and red version and GreenSeeker-green and red version. Remote sensing angle from the sensor head to the canopy of rice was adjusted to $45^{\circ}$, $70^{\circ}$ and $90^{\circ}$ degree because of difference in the density of plant and the sensing angle. The reflectance indices obtained ground-based remote sensor were correlated with the biomass of rice at the early growth stage and at the harvest with $70^{\circ}$ and $90^{\circ}$ degree of sensor angle. The reflectance indices at the 52th Day After Transplanting (DAT) and the 59th DAT, critical season, were positively correlated with dry weight and nitrogen uptake. Specially NDVI at the 59th was significantly correlated with the mentioned parameters. Based on the result of this study, rNDVI by GreenSeeker on $70^{\circ}$ degree of angle at the 59th DAT in Chucheong and rNDVI by Crop Circle on $70^{\circ}$ degree of angle and gNDVI by GreenSeeker on $70^{\circ}$ degree of angle at the 59th DAT in Joonam can be useful for estimation of dry weight and nitrogen uptake. Moreover, sufficiency index estimated by reflectance index at the 59th DAT can be useful for the estimation of N-fertilizer level application and can be used as a model for N-top dressing fertilizer management.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.292-297
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• 2006

A research was carried out to investigate the release pattern of slow release nitrogen fertilizer compound(SRNC) that is latex coated urea(LCU) and to recommend the application rate of the fertilizer at dry seeding rice culture in Honam plain area. The experiment was conducted at experimental field(Jeonbug series, fine silty, mixed, nonacid, mesic family of Fluvaquentic Endoaquepts) of National Honam Agricultural Research Institute. A medium late maturing rice variety (Dongjinbyeo) was seeded at the rate of $60kg\;ha^{-1}$ by drill seeder on April 1, 1997 and March 30, 1998. Fertilizer application rate was $160-90-110kg\;ha^{-1}$ for $N-P_2O_5-K_2O$. Soil ammonium nitrate($NH_4-N$) contents remained higher in all SRNC plots than conventional ones and higher with the increase of SRNC application rate until panicle formation stage, but the contents was higher in the conventional than NRNC plots at the heading stage. The plant hight was taller in SRNC than conventional plots until maximum tiller stage, but became similar in both conventional and SRNC plots at heading stage. The culm and panicle number was greater in SRNC than conventional plots throughout all growth stage, but the effective tiller rate was higher in conventional ones. Nitrogen efficiency was higher in the SRNC than conventional plots, but the efficiency was decreasing with the higher SRNC level. The spikelet number per unit area was greater in SRNC than conventional plots, and increased with higher SRNC level. The more spikelet number with higher NRNC level resulted in lower 1,000-grain weight. The rice yield in conventional plot was similar with only 60% SRNC level, but lower than 80% and 100% SRNC levels. However, slight lodging was observed in 100% SRNC level. In conclusions, we recommend NRNC application level as 80% of standard nitrogen application for early dry seeding culture of rice Honam plain area.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.1
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• pp.81-88
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• 1999

A field experiment with 200, 400 and $600kg{\cdot}N/ha/year$ application levels was carried out to study the nitrate nitrogen accumulation and forage yield of sorghum sudangrass hybrid(Xtragraze II) at Iksan College Farm in 1995. The nitrate nitrogen contents were increased by the application of nitrogen and decreased as the plant matured, then the accumulation of nitrate nitrogen started from 200kg application, and exceeded the safe level of ruminants at the level of 400kg application during the whole growing period. In the early stage of growth, nitrate nitrogen contents of sorghum sudangrass hybrid were increased by rainfall during the dry season, but these contents are almost kept constantly at the low level in the later stage of growth. Accumulation of nitrate nitrogen in the morning had a greater tendency than that of the afternoon. A sum exceeding $200kg{\cdot}N$ does not necessarily result in increase the amount of nitrate nitrogen in sorghum sudangrass hybrid.

• Korean Journal of Environmental Agriculture
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• v.1 no.1
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• pp.59-64
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• 1982

Studies on the effect of soil moisture, different seasons, harvesting periods and nitrogen application on the nitrate content of radish(Raphanus sativus L. var. niger(Mill.) S. Kerner) were carried out in pot and green house. The results are as follows; The low level of soil moisture leads to an increased nitrate accumulation in radish root. The nitrate content was found to be higher in spring crops and lower in summer ones. It was decreased during harvesting period. The application of nitrogen fertilizer increased the nitrate content in radish root. We found the highest content in petioles with lesser content in roots and leaf blades in that order. The multiple regression analysis and the nutritional value of nitrate content in radish were discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.2
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• pp.187-202
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• 1976

Experiment were conducted to study the photosynthetic ability of several rice varieties and the influence of the drymatter production on the yield components of the rice plant, especially in ripening period. The photosynthetic ability at the ripening period, the varieties were classified into two groups as relatively high capacity and low capacity. With the earlier the transplanting date and the higher the N-content leaf blade, the greater the ratio of reserved assimilates befere heading time to the ear. This could be support the fact that the rate of full-ripened grains or grain yield of 'Tongil' variety may increased by the change of environment condition.condition.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.2
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• pp.81-90
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• 2003

This pot experiment was conducted to find out the effects of boron application(B$_{0}$; 0.0, B$_1$; 0.2, $B_2$;2.0, $B_3$;6.0, $B_3$;6.0, $B_4$;15.0me B/pot) on the forage performance in the pure and mixed swards of orchardgrass and white clover. This 1st part was concerned with the changes in the growth, flowers and flower buds, and roots/nodules of forages. The results obtained are summarized as follows: 1. At the $B_3$ and $B_4$ treatments, the B toxicity was more seriously in white clover than in orchardgrass in the first half of cutting orders, and reduced in the latter half. In white clover, it was more worsened in a mixture than in a pure culture. It was somewhat reduced at the best growth stage of each forage. 2. In orchardgrass, the B toxicity($B_3$,$ B_4$) showed the chlorosis on leaf tips, shallow leaf, little tillers, and weak stems. Whereas it showed the chlorosis/necrosis on old leaf edge, little and weak stolons in white clover. 3. Comparing with the B deficiency($B_{0}$ , $B_1$) and toxicity($B_3$, $B_4$), the optimum B application($B_2$) influenced markedly good growth of shoot, root, nodule, and flower (flower number, blooming period, early full flower) in white clover. 4. Comparing with orchardgrass, white clover was greatly influenced by the boron application. However, this responses of white clover to boron were reduced in a grass-clover mixture with additional fertilization. It was recognized that the good forage performance in a grass-clover mixture could be regulated by the adequate applications of boron and additional fertilizers.s.

• Korean Journal of Environmental Agriculture
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• v.21 no.4
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• pp.255-260
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• 2002

This study was conducted to evaluate the effect of the proper application level of anaerobic digestion waste water on rice. The waste water was from methane fermentation of pig manure to use as a liquid manure. The mixture treatment of 70% liquid manure and 30% chemical fertilizer (LM 70%+CF 30%) and 100% liquid manure (LM 100%) treatment were higher number of tiller than other treatments at the both tillering and heading stages of rice. The yields of LM 70%+CF 30% and LM 100% treatments were a little higher than that of NPK treatment, but the mixture treatment of 50% liquid manure and 50% chemical fertilizer (LM 50%+CF 50%) was a little lower yield than NPK treatment. The periodic changes of the $NH_4-N$ and $NO_3-N$ contents of the NPK and the LM 50%+CF 50% treatments in paddy soil were a little higher than those of other treatments at the early stage of rice. The $NH_4-N$ contents of NPK and the LM 50%+CF 50% treatments in irrigation water quality were higher than those of other treatments, however there was no difference in $NO_3-N$ content among the treatments. The $NH_4-N$ and $NO_3-N$ contents of non fertilizer treatment in infiltration water quality were leached a little higher than those of other treatments. It may be due to poor growth of rice following to reduce the nutrient uptake by rice and to increase relatively the nutrient leaching to the ground water. The proper application level of anaerobic digestion waste water as a liquid manure could be suggested to apply LM 70%+CF 30%. All treatments were the same amount of nitrogen content for the standard application amount on rice.