• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.3
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• pp.158-163
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• 1990

This experiment was to study the effect of pure mineral nitrogen fertilizing on seasonal distribution of dry matter yield and the advisable mineral nitrogen amounts on grassland. The results were as follows: 1. With longer regrowth periods the absolute dry matter yields and the nitrogen-efficiences due to nitrogen fertilizing increased substantially, whereas the quality declined at the relatively lesser cutting frequencies. 2. The first cut at 3-cut regimes, the first and fourth cut at 4-cut regimes, and the second and last cut at 5-and 6-cut regimes showed the highest nitrogen-efficiency, respectively. 3. By the sigmaformed process of production curve the most efficient mineral N-dressing rate per ha and cut was calculated: 42-56kg N on the 3-cut areas, 39-55kg N on the 4-cut areas, 38-47kg N on the 5-cut areas and 35-48kg N/ha/cut on the &cut areas. 4. In dependence on site and kind of calculation the economical borders were reached with the following dressings of mineral N/ha/cut: 90-100kg on the 3-cut areas, 70-100kg on the 4-cut areas and 50- 90kg on the 5-and 6-cut areas.

• The Korean Journal of Ecology
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• v.16 no.3
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• pp.329-339
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• 1993

Effects of relative light intensity and N, P fertilization on the growth and ramet dynamics of the rhizomatous plants, Arundinella hirta, Miscanthus sinensi and Spdiopogon sibiricus were studied in Chuncheon, Kangweon-Do. Ramets emerged in one pulse a year, withered in one pulse at the end of the growing season in M. sinensis and S. sibircus stands, while the birth and death pulse in A. hirta stands were two times. Total births of ramet were 9 times and 3.6 times greater in the unshaded fertilized stands of A. hirta and M. sinensis than in the shaded, However, those of S.sibiricus were 2.1 times greater in the shaded stands. Flowering rates of A. hirta, M.sinensis and S.sibiricus I the unshaded fertilized stands were 1.8, 2.7 and 1.04 times greater than in the shaded unfertilized stands, respectively. Height of ramets of A. hirta and M.sinensis were the hightest in the unshaded fertilized stands. However, that of s.sibiricus was the highest in the shaded fertilized stand. Aboveground production of A.hirta in the fertilized stand was 2.4 times greater in the unshaded stand than in the shaded one. Results of inflorescence frequency, shoot height and the ratio of aboveground to belowground were smiliar to the total births. The added fertilizer markedly increased the ramet density and the shoot productivity of three rhizomatous plants, especially of A. hirta.

• Weed & Turfgrass Science
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• v.7 no.1
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• pp.76-86
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• 2018

Turfgrass species were evaluated for their rooting and foliar characteristics, and their interaction with the soil. The rooting system was divided into three compartments, one above another, such that the top and bottom compartments of the root system could be supplied with a nutrient deprived solution. Exposure of parts of the roots to nitrate deprivation caused a localised retardation of root initiation and extension, compared with zones receiving the full supply of nutrients. This resulted in considerable modification to root form, coupled with a significant depression in foliar growth. The extension of roots was the least affected by the deprivation of potassium. Phosphate and calcium deprivations gave rise to similar responses in root and foliar formation. Results from this study showed that external concentrations of nitrogen, phosphorus, potassium and calcium are required by the root system in varying amounts for optimal growth of roots. Turfgrass coverage and turf quality ratings further reinforced these findings. No significant difference was observed between the different grasses examined here. All three species responded similarly to the deprivation of the various nutrients. Results from this study confirmed that targeted fertilization programs are beneficial and can help reduce cost, chemical usage and prevent leachate and contamination.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.2
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• pp.128-133
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• 1994

This study was carried out to get agronomic information about the tobacco culture in paddy soil where incidence of grey tobacco leaves used to appearly uptake of iron, manganese and chlorine due to soil acidity and high water level. Application of lime to paddy soil(pH5.4-5.6) reduced content of iron, manganese known as proceeding materials giving rise to variegated grey tobacco after curing, compared with non-treatment. Grey leaves were found mainly at lower and middle stalk positions, and incidence of grey tobacco was lowered by application of lime in the well drained field but was not affected by level of fertilizer application. Amendment of soil acidity by lime tended to decrease chlorine and manganese content in leaves. Nicotine and mangenese content of leaves were lowered by reduction of one-quarter fertilizer level. In case of lime treatment, increase of yield reached to 4-6% comparing with those of non-treatment but price per kg was not affected. Reduction of N fertilizer level to three-quarters had the equal yield but high quality of leaf comparing with standard fertilization in paddy field.

• Journal of Korea Foresty Energy
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• v.19 no.1
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• pp.13-19
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• 2000

This study was aimed to investigate the effect of several stimulatory trements of flower and seed growth on the reproductive and vegetative growth of Tilia amurensis RUBP. The effects of mounded planting, girdling, root-pruning, bending and foliar fertilizer application on the fifteen to forty yead-old tress growing in the experimental plantation at the Konkuk University and the National forest at the Daegwanryung were measured. The following results were obtained: (1) The number and the longitydinal growth of internode were reduced by the treatments. The xylem growth of the longitudited more greatly than the bark growth by all the treatments. (2)The increasong rate of the brand angle as compared to that of the control was 2.11% in the girdling treatment, 31.61% in the mounded planting treatment, and 22.14% in root-pruning treatment. (3) The foliar application of fertilizer(N, P, K, and B) before flowering increased leaf and stem growth, that one after pollen fertilization increased the fruit growth. (4)The foliar application of fertilizer before flowering increased the xylem growth while that after pollen fertilization increased the bark growth. (5)The stimulatory effects of root pruning and branch bending on the flowering and seed growth were shown relatively less than that of mounded planting. The effect of the moinded planting on the yield of the seeds has remained continuously every year since planting the trees.

• Korean Journal of Environmental Agriculture
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• v.41 no.3
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• pp.167-176
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• 2022

BACKGROUND: Nitrogen (N) is an important element for turfgrass (Zoysia matrella) growth; however, standard N application rate for turfgrass is not established yet. This study was conducted to evaluate the effect of N application rates on the growth and quality of turfgrass for establishment of standard N application rate. METHODS AND RESULTS: Treatments were as follows; control (0 N g/m²/month), 1N (1 N g/m²/month), 2N(2 N g/m²/month), 3N (3 N g/m²/month), 4N (4 N g/m²/month), and 5N (5 N g/m²/month). N application improved visual turfgrass quality. Compared with the control, clipping yield of all N treatments increased by 90~194%. The grass shoot weight of 3N, 4N, and 5N treatments increased by 52%, 43%, and 111%, respectively, and the stolon weight of 4N and 5N treatments increased by 412% and 201%, respectively, compared to the control. The N uptake amount and N recovery rate were estimated to be 4.10~6.28 g/m² and 14~58%, respectively. CONCLUSION(S): These results indicate that considering visual quality, clipping yield, N uptake amount, and N recovery, the application rate of 2~3 N g/m²/month was suggested to be suitable for Z. matrella production.

• Journal of Ecology and Environment
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• v.31 no.3
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• pp.167-176
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• 2008

Atmospheric N deposition has far-reaching impacts on forest ecosystems, including on-site impacts such as soil acidification, fertilization, and nutrient imbalances, and off-site environmental impacts such as nitrate leaching and nitrous oxide emission. Although chronic N deposition has been believed to lead to forest N saturation, recent evidence suggests that N retention capacity, particularly in the forest floor, can be surprisingly high even under high N deposition. This review aims to provide an overview of N retention processes in the forest floor and the implications of changing C-N interactions for C sequestration. The fate of available N in forest soils has been explained by the competitive balance between tree roots, soil heterotrophs, and nitrifiers. However, high rates of N retention have been observed in numerous N addition experiments without noticeable increases in tree growth and soil respiration. Alternative hypotheses have been proposed to explain the gap between the input and loss of N in N-enriched, C-limited systems, including abiotic immobilization and mycorrhizal assimilation, both of which do not require additional C sources to incorporate N in soil N pools. Different fates of N in the forest floor have different implications for C sequestration. N-induced tree growth can enhance C accumulation in tree biomass as observed across temperate regions. C loss from forests can amount to or outweigh C gain in N-saturated, declining forests, while another type of 'C-N decoupling' can have positive or neutral effects on soil C sequestration through hampered organic matter decomposition or abiotic N immobilization, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.6
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• pp.545-553
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• 1991

To find out the basic data for the possibility of agricultural utilization for GSA (Glutamine Synthetase Activity), the effect of nitrogen on the GSA in wheat leaf discs, the variation of GSA after light treatment and the comparative activity of GS during preservation were studied. The result of this study suggested that GSA could play an important and direct regulatory role in the nitrogen assimilation by wheat. During the growth stage of wheat its integral activity was found to closely match the organic nitrogen content. GS may therefore be the rate limiting enzyme in inorganic N assimilation. Moreover, integral GSA was closely correlated with grain yield and grain nitrogen. GSA could be suitable to utilize as a parameter for super type selection and an indicator for optimum nitrogen fertilization. Throughout the experiment, the contents of NO; were increased by N fertilization so that the NO; content was not attributable to change in the level of GSA. At investigation during dark-light transition of culture, no change in the level of GSA was observed until after 8-14 hours in the light treatment. And the level of GSA in wheat leaf discs during preservation at refrigerated storage $(-20^{\circ}C)$ was stable until 12 weeks, when its leaf discs were sampled with liquid nitrogen.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.15-19
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• 2001

This study was carried out to investigate the effect of application time and amount of rice bran on rice yield, weed occurrence, and chemical change in water as applied at the level of 1.8 Mg/ha (1.8RB) and 3.5 Mg/ha (3.5RB) through field and pot experiment. $Nitrate(NO_3\;^-)$ in the surface water and the percolated water through pot were high in application of 3.5RB, and similar in application of 1.8RB as compared to chemical fertilization. Electric conductivity in surface water were higher by application of rice bran until 25 days after rice bran application. $NH_4-N$ in soil were lower in application of rice bran, and $NO_3-N$ in soil were higher in 3.5RB at tillering stage and panicle formation stage of rice. Rice bran application(3.5RB) showed 68% of weed occurrence as compared to that of chemical fertilization. Rice yield were increased by heavy application of rice bran; 4.41 Mg/ha in 1.8RB and 4.87 Mg/ha in 3.5RB, and top dressing of nitrogen at panicle formation stage caused to increased rice yield by $14{\sim}15%$. Rice yield was also increased by early application of rice bran.

• Clinical and Experimental Reproductive Medicine
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• v.15 no.2
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• pp.135-147
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• 1988

To compare the stimulation effect of the ratio in follicle stimulating hormone and luteinizing hormone in induction of multiple follicular growth, the serum $E_2$ level, the diameter of follicle, number of aspirated follicles and cleavage rate of in vitro fertilized preovulatory oocytes as well as the pregnancy rate were evaluated. Forty one patients with irreparable tubal disease were stimulated by hMG(n=24) or FSH/hMG(n=17) for the purpose of in vitro fertilization and embryo transfer. The following results were obtained. 1. Serum estradiol($E_2$) levels on the day of hCG administration were $921.0{\pm}353.3\;pg/ml$ in hMG group and $1272.9{\pm}1060.6\;pg/ml$ in FSH/hMG group. The serum $E_2$ value of hMG group was significantly lower than that of FSH/hMG group. 2. The diameter of leading follicle by ultrasonogram on the day of hCG administration were $16.2{\pm}2.0\;mm$ in hMG group and $16.2{\pm}2.6\;mm$ in FSH/hMG group. No significant difference of follicle diameter between two groups was demonstrated. 3. The number of follicles with diameter above 10 mm by sonogram on the day of hCG injection were $3.91{\pm}2.32$ in hMG group and $6.52{\pm}3.86$ in FSH/hMG group. There was significant difference of number of follicles between two groups, (p< 0.01). 4. The number of oocytes found per patient at aspiration were $2.59{\pm}1.00$ in hMG group and 3. $76{\pm}2.31$ in FSH/hMG group. There was significant difference of number of aspirated oocytes between two groups. (p< 0.05). 5. The detection rate of preovulatory oocyte at aspiration were 68.4%(39/57) in hMG group (n=22) and 77.6%(38/49) in FSH/hMG group (n=13). 6. The cleavage rate of preovulatory oocyte at 44 hours after insemination were 74.4%(29/39) in hMG group(n=22) and 81.6%(31/38) in FSH/hMG group (n=13). When only hMG was used, one pregnancy was established in 15 patients to whom 29 zygotes were transferred. And a full term normal female baby was delivered by elective cesarean section. In the FSH/hMG group, five pregnancies out of 9 transferred patients were confirmed by serum ${\beta}-hCG$. Two pregnancies were spontaneously aborted before the 6th week of pregnancy. One patient aborted her baby at the 18th week of pregnancy because of incompetent internal os of the cervix. Two patients delivered two full term babies by elective cesarean section. From the above findings, paralell with the increase in the ratio of exogenous follicle stimulating hormone to luteinizing hormone, an increase in oocyte recovery was observed as well as an improvements in pregnancy rate. It was concluded that FSH enrichment early in the follicular phase had a beneficial effect in the controlled ovarian hyperstimulation.