• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.294-299
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• 2000

In order to find out the effects of shading and nitrogen fertilization on the accumulation of $NO_3\;^-$ in leaves of lettuce, lettuce plants were cultivated in the pots under glasshouse condition with different rates of shading(0, 50%) and nitrogen fertilization(100, 180, 200, 300, $400\;kg{\cdot}ha^{-1}$). The pH value was lower in soil after experiment than before experiment, whereas, contents of EC and $NO_3-N$ were higher. As the amounts of nitrogen fertilization were increased, pHs were decreased, but EC and the contents of $NO_3-N$ were increased. At the nitrogen fertilizations of 100, 180, 200, 300 and $400\;kg{\cdot}ha^{-1}$, the germination rates of lettuce were decreased to 84, 78, 76, 72 and 74%, and survival rates were also decreased to 94, 94, 90, 60 and 46%, respectively. However, the fresh weight of lettuce was highest at $45\;g{\cdot}plant^{-1}$ in the recommended fertilizer $plot(180\;kg{\cdot}ha^{-1})$ with non-shading condition. The contents of $NO_3\;^-$ in the leaves of lettuce were increased 2.8-4.1 times under 50% shading conditions than that under non-shading condition. It kept increasing up to seven order of growth phase; however, it started to decrease after eight order phase. Nitrate reductase activity of lettuce in non-shading condition was higher than that in 50% shading condition.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.3
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• pp.293-299
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• 1995

Objective: To investigate the effects of sperm morphology and their co-incubation with oocytes on the outcome of IVF and ICSI. Design: Strict morphology of washed sperm was assessed by Diff-Quick staining method before or after insemination. And the relationships between strict morphology and outcome (fertilization, embryo development and pregnancy) of IVF(with co-incubation) and ICSI (without co-incubation) were determined. Patients: Two-hundreds-and-sixty-three cycles of IVF and ninety-six cycles of ICSI were analyzed in order to clarify the influence of strict sperm morphology of spermatozoa on outcome of IVF and ICSI. These were divided into four groups. according to fertilization method and sperm morphology(Group 1: IVF, ${\geq}$12%, n:227; Group 2: IVF, <12%, n:36; Group 3: ICSI, ${\geq}$ 12%, n=48; Group 4: ICSI, <12%, n=48). Results: The fertilization rates of better morphology groups were higher than those of poor groups: Group 1(68.1%) > Group 2(62.1%), Group 3(78.1%) > Group 4(71.5%). There was no difference in embryo cleavage rates among four groups (>90%), Regarded with the good embryo rates, Group 1(56.8%) was significantly higher than Group 2(42.3%)(P<0.01), but there was no difference between Group 3(64.7%) and Group 4(61.2%). The pregnancy rates were also higher in better morphology groups as well as fertilization rates: Group 1(34.8%)> Group 2(16.7%)(p<0.05), Group 3(40.0%) > Group 4(23.0%)(p=0.08). Conclusion: Co-incubation with poor morphology sperm might adversely affect the quality of embryos. And strict sperm morphology may represent the ability to establish successful pregnancy. In short, the strict sperm morphology can be a good predictor of IVF and ICSI outcome.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.829-846
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• 2015

This study was conducted to determine the effects of organic fertilization rates on the nutrient accumulation and recovery in radish (Raphanus sativus L.) as well as growth and yield of radish in Jeju island. An understanding the relationships between organic fertilization rate, crop nutrient recovery and crop yield can assist in making organic fertilizer recommendation which balances crop value and environmental risk in organic cultivation. Nitrogen (T-N), phosphate ($P_2O_5$) and potassium ($K_2O$) were applied at 0, 115-35-40, 230-70-80 (standard application rate), 460-140-160, 230-200-100 (recommended application rate) and 158-53-35 kg/ha (customary application rate), respectively as the broadcast application of mixed organic fertilizer (N 4.5% - $P_2O_5$ 1.5% - $K_2O$ 1%) in combination with langbeinite ($K_2O$ 22%), 100% at sowing period. The organic fertilizer was made of organic materials like oil cakes. Total yield of radish, as fresh weight of roots, increased with increasing organic fertilizer doses to a maximum at rate of standard or soil-testing application. Nitrogen, phosphate and potassium accumulations of radish increased curvilinearly with increasing organic fertilization rate to a maximum at rate of N 460 - $P_2O_5$ 140 - $K_2O$ 160 kg/ha. However, nitrogen, phosphate and potassium use efficiency of applied organic fertilizer decreased curvilinearly or linearly with increasing organic fertilization rate. Application of organic fertilizer in combination with langbeinite (as a potassium source) had significant effect on the yield of radish. Organic fertilization on a basis of standard or soil-testing application rate is recommended for maximun radish yield in organic cultivation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.7
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• pp.57-69
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• 2003

To evaluate nutrient dynamics with different fertilization in paddy field and develop water quality model, mass balance analysis was performed during growing season of 2001-2002 in field experimental plots irrigated with groundwater. As a result of water balance analysis, most of outflow was surface drainage as about half of total outflow and about 500mm was lost by evapotranspiration. The water budget was well balanced. The runoff from paddy field was influenced by rainfall and forced drain. Especially runoff during early cultural periods more depends on the forced drain. As a result of mass balance analysis, most of nutrient was input by fertilization and lost by plant uptake. Significant amount of nitrogen were supplied by precipitation and input from upper paddy field, comprising 12%∼28% of total inflow. Nutrient loading by surface drainage was occurred showing about 15%∼29% for T-N and 6%∼13% for T-P. The response of rice yield with different fertilization was not significant in this study. Water quality model for paddy field developed using Dirac delta function and continuous source was calibrated and validated to surface water quality monitoring data. It demonstrates good agreement between observed and simulated. The nutrient concentration of surface water at paddy field was significantly influenced by fertilization. During early cultural periods when significant amount of fertilizer was applied, surface drainage from paddy field can cause serious water quality problem. Therefore, reducing surface drainage during fertilization period can reduce nutrient loading from paddy fields. Shallow irrigation, raising the weir height in diked rice fields, and minimizing forced surface drainage are suggested to reduce surface drainage outflow.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.172-175
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• 2003

The regression equations of dry weight of planktonic biomass upon physico-chemical characteristics of fifteen ponds in three replicates under the influence of artificial feed, broiler manure, buffalo manure, N:P:K (25:25:0) and a control pond was obtained after one year of experimental period by using stepwise regression method. Water samples from each of the ponds were analyzed daily. However, the average values were calculated on the basis of 15 day intervals designated as fortnight. In artificial feed supplemented pond the regression of average nitrates on dry weight of planktonic biomass accounted for 71.7% of the variation in biomass. In broiler manure fertilization pond the regression of total nitrogen on dry weight of planktonic biomass held it responsible for more than 74.6% of variation in biomass. In buffalo's manure fertilized pond more than 82% of the variations in biomass were due to total nitrogen. In case of N:P:K (25:25:0) treated pond 66% of the variation in the dry weight of planktonic biomass was due to average nitrates. The control pond showed the dependence of biomass on light penetration. This equation explained more than 62 percent of variation in biomass. Other variables also showed some contribution towards variation in biomass under all the treatments in these regression studies.

• Korean Journal of Organic Agriculture
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• v.12 no.2
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• pp.209-217
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• 2004

The aim of this experiment was to investigate the effects of applying times and dilution rates of cattle slurry on dry matter yields of orchard grass. Cattle slurry was applied at the rates of average mineral nitrogen fertilizer equivalent to 150 kg/ha/year in 3 cutting frequency. Significantly higher dry matter yields than that of no fertilization (3.04 ton DM/ha) were recorded in the application of diluted cattle slurry(5.38~6.25 ton DM/ha) (p<0.05). Especially, this tendency was shown with higher annual dry matter yields at the partitioned dressing times, such as at the applications for 1st and 2nd growth, 1st and 3rd growth, and 1st, 2nd and 3rd growth respectively. The yields of annual dry matter both at fertilizing phosphorus and potassium, and phosphorus, potassium and nitrogen were higher than no fertilization as 5.41 tons and 8.78 tons per ha respectively. However, with application of diluted cattle slurry, dry matter yield par year (5.84 ton DM/ha) was higher than those of fertilizing phosphorus and potassium. The efficiencies of dry matter production with mineral and cattle slurry nitrogen application (kg DM/kg N) were 225 and 15.8~18.7 kg DM/kg N respectively. Especially, these tendencies were higher in diluted application plots than in no-diluted application plots of cattle slurry.

• Asian Journal of Turfgrass Science
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• v.4 no.1
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• pp.5-11
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• 1990

Korean Lawn. Zoysia japonica Steud. is the type of a perennial warm-season turfgrass keeping green leaf color for 5 months from May to September in natural condition in Korea. This Studies were carried out to obtain the effects of N-P-K fertilization, regrowth capacity after mowing and chlorophyll contents on prolongation of the green leaf color period in Zoysia japonica Steud turfgrass areas. The results obtained are summarized as follows ; 1.The effects of nitrogen fertilizer application in Zoysia japonica Steud, turfgrass areas were affected on regrowth ability after mowing green color of leaf canopies and chlorophyll contents, respectively(P<.05) 2.A experimental plots which applied 51 g/m$^2$/10 weeks of N$_3$P$_1$K$_1$fertilizer, there were high significant effects on prolongation of the green leaf color period and the plots of phosphorus and potassium had additive effects. 3.Prolongation of the green leaf color period to the last of October was obviously possible by slow degrees in proportation to increment of the fertilizer. However, it is interpreted that more prolongation of the green period is impossible with N-P-K fertilization and irrigation treatments. unless the intermediate turfgrasses between $C_3$ and $C_4$plants must be found and bred.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.5
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• pp.365-372
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• 2013

Crop development and nutrient availability are strongly influenced by soil salinity levels. This study was conducted to investigate the effect of rice straw and nitrogen (N) fertilizer for silage barley under various soil salinity levels at Saemangeum reclaimed tidal land. Three levels of rice straw (0, 2.5, 5.0 ton rice straw $ha^{-1}$) and N (0, 150, 225 kg N $ha^{-1}$) were applied at 0.04, 0.23, 0.35% soil salinity levels. Biomass yield of silage barley was influenced by the interactions between rice straw application and N fertilization. Although there was no single effect of rice straw application on biomass yield, it was significantly increased with N application and a rice straw application of 5.0 ton $ha^{-1}$. Sodium content in silage barley was significantly lower at 0.04% salinity level, and but it was statistically increased with increasing soil salinity levels. Forage qualities such as total digestible nutrients and relative feed value of silage barley were significantly higher with N application at 0.04% salinity level, but there was no effect of rice straw application. Soil organic matter content was increased with N and rice straw application regardless of soil salinity level. The results of this study showed that the effect of rice straw and N fertilization on silage barley was influenced by soil salinity levels, which indicates that the management practice of silage barley at Saemangeum reclaimed tidal land should consider soil salinity levels.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.4
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• pp.271-280
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• 1994

The aim of this experiment was to investigate the effects of fertilizing mineral nitrogen on dry matter yield of Reed canarygrass and also to estimate proper levels of fertilizing nitrogen when uncultivated rice paddy rapidly increased these days, was used for the production if Reed canarygrass. \ulcornerhe results are as follows. 1. Relative dry matter according to cutting frequency was appeared the highest at the 2nd cut for 3 and 4 cutting frequencies, and the 3rd cut for 5 cutting frequency. Those were 43.1, 34.0 and 34.1 % respectively. 2. When using only phosphrous and potassium, the average dry matter per year and ha was between 9.0 and 12.0 tons(3, 4 and 5 cutting frequency) and the highest dry matter was shown at 5 cutting frequency. 3. In accordance to the increase in the fertilization of nitorgen, the yield of dry matter was increased and, when 30 kg/ha/cut of mineral nitrogen was added, the biggest increase rate per added nitrogen for dry matter yield per year compared to that of no fe~tilization of nitrogen was recorded and it was 2.7, 3.3, and 3.4 tons/ ha for 3, 4 and 5 cutting frequencies respectively. 4. The efficiencies of mineral nitrogen on dry matter yield(DM kg/N kg) were the highest when 30kg nitrogen was applied particularly in 3, 4 and 5 cutting frequencies(29.7, 27.2, 22.8 DM kg/N kg). It recorded the highest of all the treatments. The efficiency was actually decreased in higher application of mineral nitrogen. The total nitrogen yield efficiency was the highest in 30kg(0.45kg and 0.48kg at 4 and 5 cutting frequency) and 60kg fertilization/ha/cut (0.46kg at 3 cuting frequency) and the decreased efficiencies appeared at fertilization of higher nitrogen. 5. Economical borden of mineral nitrogen fertilization were between 199.2 and 243.3kglha at 3 cutting frequency, between 253.4 and 295.9kg at 4 cutting frequency and between 302.2 and 361.3kg at 5 cutting frequency. 6. Under the condition of this experiment, the cutting frequency leading the potential production at maximum was 3 cutting frequency. At 3 cutting frequency, the efficiency of nitrogen utilization was higher and 15 or 16 tons of dry matter was obtained which is a level of economical border at fertilization between 200 and 240kglha. It wrs possible to obtain the maximal dry matter yield(l7 tonslha) at fertilization of lower level than 400kgl ha.

• Korean Journal of Medicinal Crop Science
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• v.17 no.5
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• pp.363-368
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• 2009

To fulfill the increasing demand for a high quality of flower, we investigated the effects of nitrogen application on plant growth, yield and bioactive compounds of Chrysanthemum indicum L.. C. indicum L. was cultivated in a pot scale, and nitrogen applied with the level of 0 (N0), 50 (N50), 100 (N100), 150 (N150), 200 (N200) and $300\;(N300)\;kg\;ha^{-1}$ to suggest optimum rate of nitrogen fertilization. Phosphate and potassium applied the same amount of $80-80\;kg\;ha^{-1}$ ($P_2O_5-K_2O$) in all treatments. Growth characteristics and yields of C. indicum L. were significantly affected by nitrogen application. Maximum yield achieved in 265 and $295\;kg\;ha^{-1}$ N treatment on the whole plant and the flower parts, respectively. The nitrogen content and uptake of whole plant significantly increased by the increase of nitrogen application. Five major components of essential oil, $\alpha$-pinene, 1,8-cineol, chrysanthenone, germacrene-D, and $\alpha$-curcumene in flowerheads of C. indicum L. occupied approximately 40% of peak area, germacrene-D decreased by the increase of nitrogen application among them. However, cumambrin A contents in the flower parts of C. indicum L. were affected negatively by the increase of nitrogen application, but total yields of cumambrin A in flower part significantly increased. Conclusively, nitrogen fertilization could increase the yield of flowerheads. The optimum application level of nitrogen fertilizer might be on the range of $265-295\;kg\;ha^{-1}$ in a mountainous soil.