• Korean Journal of Soil Science and Fertilizer
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• v.18 no.3
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• pp.297-303
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• 1985

Three field experiments were conducted to define the optimum levels, yield responses and fertilization efficiencies of NPK fertilizers on peanut and survey on fertility status of 150 farmers` peanut fields was carried out for 3 years. The range of optimum rates of N, $P_2O_5$ and $K_2O$ fertilizers on peanut were 5.2-9.0, 6.4-21.0, 8.5-15.0kg/10a, respectively. The effect of NPK application were 23, 8, 16% and production efficiencies of each kg of NPK fertilizers were 6.0, 1.8, 3.4 kg, respectively. The optimum nutrient contents in soil were 250 ppm for available $P_2O_5$ and 0.8 me/100g for exchangeable K including applied ones. Available soil nutrient contents of farmers' peanut fields were mostly below the optimum range for upland soil.

• Korean Journal of Plant Resources
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• v.10 no.4
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• pp.397-400
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• 1997

The experiment was carried out to determine the optimum fertilization level showing high quality on Aralia cordata Thunb. Plant height of fertilization(27-15-27kg) was promoted significantly compared with conventional fertilization(17-9-17kg). This effect was followed with increment of blanched length. Among underground parts, main root length was increased in conventional fertilization, and more cultural year was prolonged, the more yield of dry root weight was increased. Fresh leaf yield to produce high quality of Aralia cordata plant was remarkably increased about 6% in fertilization of 27-15-27kg per 10a. As a result, to produce higher good quality of the plant. the optimum fertilization level was 27-15-27kg per 10a.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.4
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• pp.35-42
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• 2019

Organic fertilization (OF) was an effective management strategy to improve crop yield and soil fertility. Determination of optimum application rate has been received great interest as a major research field. In this study, we evaluated optimum application level of three different organic fertilizers; mixed expeller compost (MEC), mixed organic fertilizer (MOF) and organic complex fertilizer (OCF), for garlic cultivation. Treatments consisted of MEC, MOF, OCF (50, 100, 150% of standard nitrogen input), inorganic fertilizer(NPK, N-P₂O₅-K₂O : 250-78-128 kg ha^-1) and no-fertilization (control). Overall, the yields of garlic under MEC, MOF and OCF 100% (5,337, 5,617 and 5,276 kg ha^-1) were higher than under control (4,496 kg ha^-1). The 100% of three OFs treatements showed the highest yield and bulb diameter, similar with NPK, while leaf length and bulb height were not significantly different among all treatments. The 150% of three OFs rather decreased yield. The highest nitrogen use efficiency (38.4 and 38.0%) was observed in MOF 100% and OCF100%, which was the most similar with that in NPK (38.8%). As OF application rate increased, pH was decreased, but soil NO₃-N and NH₄-N were increased. There was no significant difference in soil organic matter (OM), av. P₂O₅ and Ex. cation values. From these results, 100% application of OFs could be recommended as a suitable input level for garlic cultivation, regardless of organic fertilizer types. Further study might be required to evaluate long-term OF application effect on soil health and crop productivity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.194-198
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• 2004

This study was conducted to identify the appropriate nitrogen fertilizer application rate for improving rice quality in tidal reclaimed area, at the Gyehwado substation of the Honam Agricultural Research Institute during 2002-2(103. The experimental fields contained 0.1% (low salinity) and 0.3-0.4% (medium salinity) Nacl in soil solution. Plant height at panicle formation stage was tall ay heavy nitrogen level and the effect of heavy nitrogen was higher in low than in high soil salinity condition. Heading date was not affected by applied nitrogen levels from 8 to 16 kg/10a in low soil salinity condition but it was one day later in 24 kg/10a nitrogen level when compared with the standard nitrogen level,20 kg/10a. In middle soil salinity condition, the heading date was one day earlier in 8 to 16 kg/10a and similar in 24 kg/10a, when compared with 20 kg/10a nitrogen level. And also it was four days later in middle than in low soil salinity condition. In low soil salinity condition, grain number $\textrm{m}^2$ increased but ripened grain ratio decreased as the nitrogen application increased and finally, milled rice yield was not different among heavy nitrogen application levels compared with 12 kg/10a. Head rice ratio was high and protein content was low in 12 kg/10a or lower nitrogen level. In middle soil salinity condition, grain number $\textrm{m}^2$ increased and ripened grain ratio was not affected as the nitrogen application increased. And finally, milled rice yield increased with increasing nitrogen application levels, Head rice ratio was high and protein content was not affected by nitrogen application levels. Therefore, on the basis of milled rice yield and rice grain quality inreclaimed land, the appropriate nitrogen application level would be 12 kg/10a in low soil salinity condition and 20 kg/10a in middle soil salinity condition.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.209-214
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• 1994

A study was conducted to study yield response and nutrient uptakes with N, P, K application. Its growth and root yield of Aralia continentalis was increased along with the added amount of fertilizer, and optimum fertilization rates of N, P, K were 38, 21, 18kg/10a, respectively. On the path coefficient analysis between the growth characters and root yield, its values showed in the order of plant height, root width, number of budstocks, number of branch, stem width and number of root. Relative yield of non-fertilization against fertilization of N, P, K were low in the order of N, P and K, that is, responses of fertilization on root yield of Aralia continentalis were affected greatly in the order of N, K and P, but the fertilization efficiency was high in the order of K, P and N. Calcium content was the highest and phosphorus content was the lowest among the mineral nutrients contained in the leaf, but relationships between nitrogen content and root yield was showed positive correlation the difference distinctly between the chemicals and the organics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.56-61
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• 2005

This study was carried out to elucidate the proper nitrogen application level considering rice quality in Honam plain area from 2002 to 2004 at the paddy field of Honam Agricultural Research Institute. The rice cultivars tested were Samcheonbyeo (Early maturing one), Hwaseongbyeo (Medium maturing one) and Nampyeongbyeo (Mid-late maturing one). The results are summarized as follows: The higher amount of nitrogen application resulted in greater number of panicle and grain in per unit area, but the rate of ripening and the 1,000-grain weight of brown rice decreased. The protein contents showed a tendency of increase with higher nitrogen level. The head rice yield increased by the higher nitrogen application up to 7 kg/10a for Samcheonbyeo and Hwaseongbyeo, and 9 kg/10a for Nampyeongbyeo respectively. The appropriate nitrogen application amounts, with respect to the yield of head rice, the rate of ripening and the quality of rice were found to be in range of 7 to 9 kg/10a.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.397-404
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• 2015

This study was conducted to find out the optimum nitrogen fertilization for production of good quality and high yield zoysiagrass (Zoysia japonica Steud.), the changes in chemical properties of soil in pot and field experiments treated with different levels of nitrogen fertilizer. In pot experiment, the fresh and dry weights of shoots and stolons and the number of shoots increased as nitrogen levels increased, and showed no significant between 24 and $48kg\;N\;10\;a^{-1}$. In field experiment, the shoot length, fresh and dry weights of shoots, roots and stolons, the number of shoots and total stolons length linearly increased as affected by increased nitrogen application, and were not significantly different between 24 and $32kg\;N\;10\;a^{-1}$. In both experiments, pH and exchangeable cations ($Ca^{2+}$ and $Mg^{2+}$) in soil decreased as the rate of nitrogen application increased. As a results, chemical properties of soil were more deteriorated in the plots of higher nitrogen fertilizer rate. Thus, these results demonstrated that the nitrogen fertilizer rate for maximum growth of zoysiagrass was $24kg\;N\;10\;a^{-1}$ in consideration of growth and soil condition.

• Journal of Bio-Environment Control
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• v.21 no.1
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• pp.57-65
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• 2012

Fertilization is essential to seedling production in nursery culture, but excessive fertilization can contaminate surface and ground water around the nursery. The objective of this study was to find optimal fertilization practice of container seedling production for reducing soil and water contamination around the nursery without compromising seedling quality. This study was conducted to investigate chemical properties of the growth medium, growth performance, chlorophyll fluorescence, and chlorophyll contents of larch ($Larix$ $kaempferi$) growing under three different fertilization treatments (Constant rate, Three stage rate, and Exponential rate fertilization). Root collar diameter and height of larch were not significantly different among treatments even though the nutrient supply of the exponential treatment was half that of the constant and three stage treatments. Chemical properties of the growth medium showed the same trends as root collar diameter and height. The total biomass and seedling quality index (SQI) were higher at Constant than at other treatments, but both SQI of Constant and Exponential were not significantly different. Photochemical efficiency and chlorophyll contents were lower at Exponential than at other treatments, but not significantly different among treatments. Therefore, Exponential fertilization which is 50% fertilizer of other treatments would maximize seedling growth and minimize nutrient loss.

• Horticultural Science & Technology
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• v.33 no.1
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• pp.24-30
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• 2015

This study was conducted to select proper light intensity, pot media, and fertilization level for potted Hepatica asiatica Nakai native to Korea. The plants were grown under various light intensities (shading rate, 52, 82, 90, 97%) imposed by shading net. Plants grown with 52% shading showed a low survival rate (65%). Survival rate increased as shading increased, with over 80% survival in shading above 90%. Growth indexes such as fresh weight and leaf number did not show any significant difference between shading treatments. Plants grown in a soil mixture of decomposed granite:fertilizer-amended media:Kanumatsuchi (60:10:30, v/v/v) or river sand:fertilizer-amended media:bark (50:20:30) showed over 85% survival. However, plants grown in a soil mixture of river sand:fertilizer-amended media:Kanumatsuchi (50:30:20) or upland:river sand (40:60) showed very low survival, below 60%. Leaf number and plant height were the highest in a soil mixture of decomposed granite:fertilizer-amended media:Kanumatsuchi (60:10:30) as well. To select a proper fertilization level for H. asiatica, hyponex solution diluted 1,000- or 2,000-fold were applied weekly or biweekly. The survival rate was lowest at weekly application with 1,000-fold diluted solution, and no significant difference was observed between other treatments. In conclusion, H. asiatica exhibits preferences for very low light intensity and soil with air permeability, and is adaptable to a broad range of fertilization levels.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.4
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• pp.264-269
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• 2016

The present study was conducted to establish the optimal fertilization type and method for no-tillage during the first year of No-tillage (NT) and Conventional-tillage (CT) practices for soybean, using different types of fertilizers. In this experiment, the culm length and stalk diameter showed a greater response to fertilization with surface irrigation than to conventional fertilization. The fastest flowering period (July 28) occurred using chemical fertilization applied via subsurface irrigation. Comparing maturation based on growth characteristics and flowering date revealed that fertilization with subsurface irrigation was more effective for the growth of crops than other methods. Regarding yield, there was no significant difference between livestock and chemical fertilizers in subsurface irrigation, but there were significant differences between these fertilizers when using conventional fertilization methods. Based on the results, livestock fertilizer with subsurface irrigation effectively enhanced crop quantity. Nitrogen absorption of plants using subsurface irrigation was more effective than that using conventional fertilization. Regarding phosphorus absorption of plants, chemical fertilizers showed higher absorption than did livestock fertilizers for both subsurface irrigation and conventional fertilization. Unlike nitrogen, phosphorus was highly absorbed using conventional fertilization. Absorption of phosphorus and potassium were similar but phosphorus was not absorbed using livestock fertilizers applied either using subsurface irrigation or with conventional fertilization.