• Korean Journal of Soil Science and Fertilizer
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• v.18 no.4
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• pp.386-391
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• 1985

In sandy paddy soil, the occurrence of leaf and neck blast was investigated depending upon nitrogen fertilizer application level of 10, 15, 20kg per 10a and different application method of surface application, whole layer application and integrated improvement. An occurrence of leaf and neck blast was significantly increased with increasing nitrogen application up to. 20kg/10a. Also a close relation between leaf and neck blast was observed. Effect of fungicides on blast control was 62.5-93.5 percent compared to those of no fungicides. Yield of unhulled rice was 604kg/10a in plots of no fungicides, however, it was 719kg/10a in plots with fungicides. Yield loss was 15.6% in case of blast infection.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.3
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• pp.177-184
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• 1974

An attempt was made to determine simple and the most reasonable fertilizer recommendation for barley utilizing the present knowledge about the effect of soil and climatic factors on barley response to NPK fertilizer in Korea and establishing the critical contents of available nutrients in soils. The results were summarized as follows. 1. The relationships between relative yields or fertilizers rates for maximum yields from quadratic response curves and contents of organic matter, available $P_2O_5$, exchangeable K in soils were examined. The trend was more prospective with relative yields because of smaller variation than with fertilizer rates. 2. Since the relationship between N relative yields and organic matter contents in soils was almost linear over the practical range, it was difficult to determine the critical content for nitrogen response by quadrant methods. However, 2.6%, country average of organic matter content in upland soils was recommended as the critical point. 3. There showed a trend that average optimum nitrogen rater was higher in heavy texture soils, colder regions. 4. The critical $P_2O_5$ contents in soil were 96 or 118 ppm in two different years, which were very close to the country average, 114 ppm of $P_2O_5$ contents in upland soils. The critical K content in soil was 0.32 me/100g, which was exactly coincident to the country average of exchangeable K in upland soils. 5. According to the contents of avaiiable $P_2O_5$ and exchangeable K, several ranges were established for the purpose of convenience in fertilizer recommendation, that is, very low, Low, Medium, High and very High. 6. More phosphate was recommended in the northern region, clayey soils, and paddy soils, whereas less in the southern region and sandy soils. More potash was recommended in the northern region and sandy soils, whereas less in the southern region and clayey soils. 7. The lower the PH, the more fertilizers were recommended. However, liming was considered to be more effective than increas in amount of fertilizers.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.1-4
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• 1998

The ecology of rhizome rot incidence rates between Seosan, Chungnam and Bongdong, Chonbuk province were surveyed in this experiment. The rhizome rot incidence rate of Seosan was lower than that of Bongdong. The average ginger product of former province was 1,140kg, whereas it's 818kg per 10a. in latter province. Treatment after disease incidence frequently used fungicide at Seosan. There were different soil physiological property between fields. Although Eunhari and Yulsori were belong to Bongdong province, incidence rate was low at Eunhari, contained 23% clay and high incidence rate at Yulsori, approximately contained 60% silt. Many soil chemical properties of cultivated area were belong to optimum concentration range, but phosphate(P) was higher than optimum concentration, 450-550ppm. The number of soil fungi in the middle of cultivated season tended to show the highest. Both bacteria and actinomyces` number was similar to the result of fungi. The bacteria/fungi ratio was greatly different between surveyed fields.

• Journal of Bio-Environment Control
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• v.18 no.1
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• pp.29-39
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• 2009

The influence of windbreak to minimize the ventilation velocity near the plant canopy of a greenhouse strawberry was thoroughly investigated using computational fluid dynamics (CFD) technology. Windbreaks were constructed surrounding the plant canopy to control ventilation and maintain the concentration of the supplied $CO_2$ from the soil surface close to the strawberry plants. The influence of no windbreak, 0.15 m and 0.30 m height windbreaks with varied air velocity of 0.5, 1.0 and 1.5 m/s were simulated in the study. The concentrations of supplied $CO_2$ within the plant canopy of were measured. To simplify the model, plants were not included in the final model. Considering 1.0m/s wind velocity which is the normal wind velocity of greenhouses, the concentrations of $CO_2$ were approximately 420, 580 and 653 ppm ($1{\times}10^{-9}kg/m^3$) for no windbreak, 0.15 and 0.30 m windbreak height, respectively. Considering that the maximum concentration of $CO_2$ for the strawberry plants was around 600-800 ppm, the 0.30 m windbreak height is highly recommended. This study revealed that the windbreak was very effective in preserving $CO_2$ gas within the plant canopy. More so, the study also proved that the CFD technique can be used to determine the concentration of $CO_2$ within the plant canopy for the plants consumption at any designed condition. For an in-depth application of this study, the plants as well as the different conditions for $CO_2$ utilization, etc. should be considered.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.49-56
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• 2019

This experiment was conducted to select an optimum application rate of blended biochar pellet as slow release fertilizer during cabbage cultivation. The blended biochar pellet made with a combination(4:6) of biochar and pig manure compost with unloading N, P, K solutions for adjusting about 9% of total nitrogen(TN). The treatments were consisted of the control as recommended application rates for cabbage cultivation in National Institute of Agricultural Sciences, N 40%, N 40% and 0.07M MgO and N 60 % of the blended biochar pellet, respectively, based on nitrogen application of recommended rates to cabbage cultivation. Changes of $NH_4-N$, $NO_3-N$, $P_2O_5$ and $K_2O$ concentrations in the soil and growth characteristic and yield components were investigated and observed during the cabbage cultivation. The experimental result shown that contents of $NH_4-N$, $NO_3-N$ and $K_2O$ of soil in the N 40% were significantly difference(p<0.01) with the control. $P_2O_5$ concentrations of soil in the N 40% were highest among the treatments. The fresh weight per cabbage in the N 40% was not significantly different(p>0.05) from the control, but in the N 40% and 0.07M MgO and N 60% was lower than that of the control. It was considered that an optimum blended biochar application rate for cabbage cultivation was 40% of recommended nitrogen application.

• Korean Journal of Agricultural Science
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• v.36 no.2
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• pp.135-145
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• 2009

This research was conducted to investigate the effect of various phosphorus concentrations in fertilizer solution on growth of and nutrient uptake by 'Chugyang' egg plant (Solanum melongena L.). Tissue and soil analyses were also conducted to set the threshold levels of phosphorus in plants when disorders develop for phosphorus deficiency or excess. Brown and purple areas developed on the margin of mature leaves and it enlarged rapidly in P deficient plants. The fruits in P deficient plants were small and dull purple in color. When P were excess in fertigation solution, the margins of lower leaves became scorched and it enlarged to inner part of the leaves. The fruits of P excess plants became small and had the curl shape. The tissue $PO_4$-P contents in the most recently fully expanded leaves and dry weight of full above ground plant tissue at 35 days after transplanting showed quadratic response ($y=0.7887+0.2394x-0.0197x^2$) and cubic response ($y=10.43+14.47x-4.7642x^2+0.3977x^3$) to elevated $PO_4$-P concentrations, respectively. When 10% reduction in dry weight set to threshold levels, optimum tissue $PO_4$-P contents are between 0.98 to 1.35%. The yield determined at 150 days after transplanting also showed cubic response to elevated phosphorus concentrations in fertigation solution ($y=1194.6+1502.2x-454.5x^2+35.64x^3$). When the 10% reduction in yield is set to threshold levels, the tissue $PO_4$-P contents for maximum yield should be around 1.53% to 2.25% in most recently fully expanded leaves at 150 days after transplanting.

• Horticultural Science & Technology
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• v.34 no.2
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• pp.220-227
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• 2016

The objective of this research was to investigate the influence of application rates of dolomitic lime in the acid substrate on the mitigation of high bicarbonate damage in 'Seolhyang' strawberry. For this purpose, an acid substrate was formulated by mixing of sphagnum peat moss and pine bark with the ratio of 5:5 (v/v). The pH, EC and CEC of the substrate analyzed before application of dolomite were 4.07, $0.46dS{\cdot}m^{-1}$, and $91.3cmol+/kg^{-1}$, respectively. To adjust the pH of substrate, various amounts of dolomitic lime [$CaMg(CO_3)_2$] such as 0 (control), 1, 2, 3, and $4g{\cdot}L^{-1}$ were added during substrate formulation. Then, seedlings with 3 leaf stage were transplanted as mother plants and those were fed with Hoagland solution containing $240mg{\cdot}L^{-1}$ of the $HCO_3{^-}$. The growth parameters of mother plants 140 days after transplanting, such as plant height, chlorophyll content, and fresh weight were the highest in the treatments of 2 and $3g{\cdot}L^{-1}$ of dolomitic lime. The physiological disorders in mother plants were not observed in the 1, 2 and $3g{\cdot}L^{-1}$ treatments, but the symptoms of Ca, K and B deficiencies were observed in the 0 and $4g{\cdot}L^{-1}$ treatments. During the propagation period, the number of daughter plants derived from each mother plant were 21.0, 29.5, 35.8, 27.3 and 16.0 in the treatments of 0, 1, 2, 3 and $4g{\cdot}L^{-1}$, respectively. The substrate pH during cultivation of mother plants were maintained at appropriate levels for the 1 and $2g{\cdot}L^{-1}$ treatments, whereas it was the highest in $4g{\cdot}L^{-1}$ treatment. The contents of macro- and micro-elements in the above ground tissue were the highest in $2g{\cdot}L^{-1}$ and the lowest in $4g{\cdot}L^{-1}$ lime treatments. Above results suggest that the bicarbonate injury originated from ground water can be mitigated by adjusting the amount of dolomitic lime incorporated into the acid substrate.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.3
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• pp.238-245
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• 1998

The reasonable level of nitrogen fertilizer is a key factor to reduce environmental contamination as well as to increase crop yield and quality. The treatments are $N=42kg\;10a^{-1}$, $N=48kg\;10a^{-1}$, $N=54kg\;10a^{-1}$. $N=60kg\;10a^{-1}$. $N=72kg\;10a^{-1}$ and $N=150kg\;10a^{-1}$. Analytical results of yield and quality of tea leaves harvested the second time are summarized as follows: The soil of experimental field was higher in organic matter($49.9g\;kg^{-1}$) and available phosphate($937mg\;kg^{-1}$) compared to the general field but lower in pH(5.07) compared to the general field. When the amount of nitrogen fertilizer application was raised, the yield of tea leaves, the content of nitrogen, total free amino acids, caffeine and chlorophyll increased: however, the yield of tea leaves increased to excessive levels. On the other hand, the increased level of nitrogen fertilizer did not show any difference in the contents of vitamin C and tannin. Eleven kinds of amino acids were isolated from second harvested leaves of tea where the content of theanine occupied over 50%, and content of $665{\sim}763mg\;100g^{-1}$. The contents of fatty acids and catechin did not show correlation with application level of nitrogen fertilizer. The content of fatty acid was produced $1,742{\sim}2,643mg\;100g^{-1}$, and content of catechin was produced 12.47~13.54%. In scoring test, $N=60kg\;10a^{-1}$ treatment was 0.5~6.0 point higher compared to other treatments. Consequently, $N=60kg\;10a^{-1}$ is considered to be the best level of nitrogen fertilizer in terms of decreased environmental contamination as well as to increase crop yield and quality.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.131-137
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• 1986

Korean lawn, Zoysia japonica STEUD, is the type of a perennial warm-season lawn grass that has a naturally green period during 5 months from May to September. This study was carried out to detect the effects of N-P-K fertilization, regrowth capacity after mowing and chlorophyll contents on prolongation of the green period in Zoysia japonica grasslands. The results obtained are summarized as follows: 1. The effects of nitrogen fertilizer application on Zoysia japonica grasslands were affected on regrowth capacity after mowing, green color of leaf canopies and chlorophyll contents, respectively. 2. A the experimental plots which applied 45g/$m^2$/10 weeks of $N_3$ fertilizer, there were high significant effects on prolongation of the green period and the plots of phosphorus and potassium had additive effects. 3. Prolongation of the green period to the last ten days of October was obviously possible by slow degrees in proportion to increment of N-P-K fertilization. 4. 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 CROP SCIENCE
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• v.58 no.3
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• pp.239-252
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• 2013

Agronomic characteristics and grain properties of Korean wheat of 175 farmers in nationwide for two years, 2010/2011 and 2011/2012, were evaluated to support basic data for improving grain quality of Korean wheat and enhancing Korean wheat consumption. Agronomic characteristics, including culm length, spike length, number of $spike/m^2$ and rate of off-type plant, and grain properties, including 1000 kernel weight, test weight, moisture, ash and protein content, were influenced by year and location. Number of $spike/m^2$, test weight, moisture, ash and protein content of wheat cultivated in 2011 were higher than those of 2012 and culm length, spike length, rate of off-type plant and 1000 kernel weight of 2012 were higher than those of 2011. Wheat cultivated in southern part of Korea showed higher culm length and 1000 kernel weight and lower test weight than those of northern part of Korea. Spike length, number of $spike/m^2$ and test weight were reduced by additional fertilization after mid of March, although there was no significant difference between date of additional fertilization and grain properties. Cultivated wheats in Jeollabuk-do showed lower ash content and higher protein content than those of other provinces and cultivated wheats in Jeollanam-do exhibited higher ash content than that of other provinces. As amount of fertilization increased, culm length, 1000 kernel weight and protein content increased and spike length and ash content were decreased, although date of additional fertilization did not effect on agronomic characteristics and grain properties. Amount of fertilization was positively correlated with 1000 kernel weight and protein content (r = 0.159, P < 0.05 and r = 0.212, P < 0.01, respectively) and was negatively correlated with ash content (r = -0.185, P < 0.05). Thousand kernel weight was negatively correlated with ash content (r = -0.226, P < 0.01) and positively correlated with protein content (r = 0.207, P < 0.01). Ash content increased as test weight and culm length decreased and 1000 kernel weight was influenced by culm and spike length (r = 0.397, P < 0.001 and r = -0.205, P < 0.01, respectively).