• Korean journal of applied entomology
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• v.47 no.3
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• pp.217-226
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• 2008

Development of T. urticae was studied on the leaves of eggplant grown in hydroponics with potash contents of 0 mM, 2 mM, 6 mM, and 12 mM. As the levels of potash increased, that of nitrogen decreased and that of P, K, Mg increased in the plant. While contents of crude protein and fiber decreased, those of ash and sugar increased. Carbohydrate content was the highest at 2 mM. Water contents increased as those of potash increased with the exception at 0 mM. Biomass was the heaviest as 552.7 g at 6 mM and the lightest at 0 mM. Leaf thickness and the content of chlorophyll increased as the content of potash increased. Laboratory leaf disc tests provided with various potash levels revealed that feeding and oviposition preferences of T. urticae were high at 6 mM and 12 mM, respectively. Ratio of damaged leaf by naturally occurring T. urticae on eggplants of 99 days post-transplant in the greenhouse was the highest at 6 mM. Development of immature stages of T. urticae shortened as the levels of potash increased with a less tendancy in male than in female. No differences were detected in adult longevity and oviposition period but the number of eggs laid was the most as 84.7 at 6 mM and the least as 40.6 at 0 mM. There were no differences in the rate of egg hatch and the ratio of sex. $R_o,\;r_m,\;and\;{\lambda}$ were the highest at 6 mM and the lowest at 0 mM. T and Dt were the lowest at 6 mM and the highest at 0 mM. There was a descending trand of T. urticae developmet when levels of potash either gets high or low in the hydroponics.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.6
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• pp.413-420
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• 2001

To prevent salt accumulation in cut-flower rose soil through proper nutrient management, the optimum concentration of nitrogen and potassium for fertigation was investigated. For the purpose, 'Noblesse' cut-flower roses was transplanted to a sandy loam soil in a plastic house and four nutrient levels (0, 25, 50 and $100mg\;l^{-1}$) of N and K separately were applied by drip-irrigation under -20 kPa of soil moisture tension. The growth and yield responses were assessed in terms of the length, weight and number of cut-flower roses, and the nutrient availability absorbed by plant. The length of cut-flowers was not affected by N concentration, but the weight and number of cut-flowers were greatest at $50mg\;N\;l^{-1}$. For K, the length and weight of cut-flowers were greatest at 25 and $50mg\;l^{-1}$, but the number of cut-flowers were remarkably great at $50mg\;l^{-1}$. Despite of increase of N and K fertigation concentration ranged from 25 to $100mg\;l^{-1}$, there was not significant difference between the uptake concentration of plant parts. As a result, the availability of N and K in $50mg\;l^{-1}$ fertigation was highest when compared to other fertigation concentrations, while the remaining amounts of N and K to soil was very low. The results of this study suggested that N and K concentrations of $50mg\;l^{-1}$ would be adequate for the fertigation of 'Noblesse' cut-flower rose.

• Korean Journal of Organic Agriculture
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• v.20 no.2
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• pp.173-183
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• 2012

This study was conducted to select promising green manure crops, providing sufficient amount of nutrients for satisfying fruit tree growth, with the overwintering cover crops grown in organic orchards in 2009. The cover covers were investigated in 13 organic orchards in Chonnam province in April and June. The dry matter in cover crops observed in April and June was the highest for Lolium multiflorum Lam. and Bromus japonicus Thunb., respectively. Total N and K production in April was the highest for Lolium multiflorum Lam, Vicia hirsuta (L.) S. F. Gray and Vicia angustifolia var. segetilis (Thuill.) K. Koch., respectively, with Bromus japonicus Thunb. in June. This study showed that the leguminous crops, Vicia hirsuta (L.) and Vicia angustifolia, would be the prospective cover covers as the both crops provided sufficient amount of N and $K_2O$ into the soil. Amount of $P_2O_5$ producing from all cover crops provided less than nutrient levels than those of recommended nutrient requirement for satisfying 10- to 15-year-old fruit tree growth.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.457-464
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• 2011

Livestock manure compost (LC) generally contains high content of phosphorus, therefore can be a substitute for phosphorus fertilizers. In this experiment of the cultivation of lettuce in green house, the possibility of LC as a subsitute for phosphorus fertilizer was investigated and the fertilizer efficiency of nitrogen and potassium in LC as compared with chemical N fertilizer (urea) and K fertilizer (potassium chloride) was examined. In proportion to the increase in the application rate of nitrogen fertilizer, soil pH declined, whereas EC and $NO_3$-N content became higher. The application of LC appeared to increase the soil content of organic matter, available phosphate, exchangeable calcium, magnesium and sodium more than that of chemical fertilizer. Supplementation of the K fertilizer by the lack amount from the application of LC resulted in the same exchangeable potassium content in soil with NPK plot in which N, P and K fertilizers were applied by the amount of soil test recommendation. The relationship between soil $NO_3$-N content and nitrogen application rate from fertilizer and compost showed as y=0.57717a+0.19760b+74.65 ($R^2$=0.6347) in which y is the soil $NO_3$-N content (mg $kg^{-1}$), a is nitrogen application rate from fertilizer and b is nitrogen application rate from compost (kg $ha^{-1}$), respectively. From this equation, the supply ability of $NO_3$-N into soil of LC exhibited about 34% (pig manure compost 37.0, chicken manure compost 34.7, cattle manure compost 23.3) of nitrogen fertilizer (urea).

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.436-441
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• 2009

The experiment was conducted to investigate the effect of nitrogen and potassium sources on growth and yield of strawberry 'Seolhyang' and 'Maehyang' in fertigation culture. The plant fresh and dry weight were higher in urea + potassium sulfate and ammonium sulfate + potassium sulfate as nitrogen and potassium sources than others in both varieties. But there were no significant difference among nitrogen and potassium sources in other growth characteristics, such as plant height, no. of leaf, crown diameter etc. Also, the marketable yield of fruit were higher in urea + potassium sulfate and ammonium sulfate + potassium sulfate in 'Seolhyang' than other treatments. 'Maehyang' was better in both treatments but there was no significant difference. The fruit qualities, such as total soluble solid, hardness, acidity, vitamin C content were not significant difference among the treatments. The acidity of soil was tended to decrease but EC was tended to increase highly in ammonium sulfate treatments as a nitrogen source. As above results, the urea and potassium sulfate were recommended as nitrogen and potassium sources for the fertigation culture of strawberry 'Seolhyang' and 'Maehyang'.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.286-293
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• 2012

This study was initiated to find out the suitable perennial ground covers naturally grown in thirteen organic orchards in Chonnam Province as a organic nutrient source for maintaining annual fruit tree growth. The ground covers were observed in April, June, and August in the orchards. Agropyron tsukusinense and Panicum virgatum observed in April and June, respectively, produced the highest dry weight, which increased amounts of N, $P_2O_5$, and $K_2O$, mineralizing from the residue in the ground covers. The occurrence of perennial ground covers in August decreased compared to April and June. Amount of residue in mowed Agropyron tsukusinense and Panicum virgatum satisfied nutrient demand (N; 20 kg/10a, $P_2O_5$; 11 kg/10a, and $K_2O$; 19 kg/10a) to achieve the annual growth of twenty-year old fruit tree.

• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.1-8
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• 2012

BACKGROUND: Organic fertilizers in watermelon cultivation are widely used to supply nutrient and organic matter. This study was conducted to investigate the effects of application rate of organic fertilizer on the watermelon growth and soil chemical properties in greenhouse METHODS AND RESULTS: The organic fertilizers used in this experiment were mixed expeller cake (MEC) and mixed organic fertilizer (MOF). The treatments were conducted with 4 levels (1.0 N, 0.7 N, 0.5 N and 0.3 N) on the basis of soil testing nitrogen fertilization (STNF) using MEC or MOF as the basal dressing, and using chemical fertilizers (CF) as the additional dressing on the rest of STNF. These fertilizations were compared to CF 1.0 N (0.3 N as the basal and 0.7 N as the additional dressing) and non fertilization (NF). The leaf area of watermelon in treatment 0.5 N and 0.3 N using MEC or MOF was similar to CF treatment. The absorbed nutrient amounts by leaf, weight and sugar contents of fruit in the 0.5 N and 0.3 N treatments were higher than other treatments. In 0.5 N and 0.3 N treatments using MEC or MOF on the basis of STNF, soil chemical properties such as electrical conductivity (EC), available $P_2O_5$ and exchangeable K concentrations after experiment showed tendency to decreasing or similar level before experiment. CONCLUSION(s): These results suggest that the MEC or MOF application as the basal dressing at the 30~50% level of STNF and CF application as the additional dressing on the rest of STNF be best to maintain adequate nutrient of soil and to increase marketable yield for watermelon.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.5
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• pp.318-324
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• 2000

Field experiment was conducted on a sandy clay loam paddy field in the Experimental Farm of the Kangwon National University for four years from 1995 to 1998 to evaluate the effect of different nitrogen fertilizers on soil property and rice yield. The size of each experimental plot was 75 m2. Basal application of fertilizer to the paddy field was on late April, and rice (cv. Odae) was sown with drill seeding on early May. Irrigation was done at 3 leaf stages after rice seeding. Electrical conductivity in soils treated with phosphate- and resin coated slow release fertilizers were relatively greater than those of the other fertilizer application. Available $P_2O_5$ concentration in soils after rice harvest increased significantly compared that in soil before field trial. Rice yield in transplanting culture were $6.516kg\;ha^{-1}$. The rice yield in the direct seeded paddy was 81.9 percents of the yield in the transplanted paddy. The rice yield in phosphate coated slow release fertilizer was the highest among various fertilizer trials in directly seeded dry paddy, while rice yield was the lowest in the organic fertilizer plus urea application. Rice yield between organic fertilizer plus urea and organic fertilizer application were not significantly different. The green manuring effect of rye in the direct seeded rice paddy in Chuncheon was low due to low temperature and short growth period.

• The Korean Journal of Mycology
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• v.25 no.2 s.81
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• pp.91-100
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• 1997

Production of alkaline carboxymethyl cellulase (CMCase) and xylanase by batch and fed-batch cultures of alkalophilic Cephalosporium sp. RYM-202 was investigated. Of carbon sources tested, wheat bran gave the highest production of those enzymes. The high levels of CMCase on carboxymethyl cellulose and xylanase on birchwood xylan suggest that the biosynthesis of CMCase and xylanase in Cephalosporium sp. RYM-202 is regulated separately at the level of enzyme induction. The temperature and pH for maximal production of those enzymes was $20^{\circ}C$ and 9.0, respectively. High concentration of wheat bran in batch fermentation resulted in the lower and delayed production of the enzymes by catabolite repression. In fed-batch fermentation with controlled feeding of 5% final wheat bran concentration, the highest activities of CMCase and xylanase were 0.39 and 9.2 units/ml, respectively, and 1.22 and 1.36 times higher respectively than those in batch fermentation on 5% wheat bran.

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.147-153
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• 2017

BACKGROUND: Soil water content strongly depends on weather condition and irrigation, and it could influence on crop nutrient use efficiency. This study was performed to assess nutrient uptake of soybean by soil water condition. METHODS AND RESULTS: In this study, nutrient leaching and crop uptake as affacted by water management practice was investigated using weighing lysimeter which is located in National institute of agricultural science, Wanju, Jeonbuk province from June 2015 to October 2016. Water supply for soybean (cv. Daewon) was managed with irrigation and rainfall. Nitrate leaching was greatest in the rainfall treatment at early July 2016. Yield of soybean in the rainfall treatment was only 25% compared to the irrigation due to the drought at flowering and podding period. The uptake of nitrogen was considerably reduced by drought whereas the uptake of phosphorus and potassium was less affected by drought. CONCLUSION: It was proven that nitrogen loss and uptake were dependent on soil water condition. Therefore, irrigation water management to maintain available soil moisture capacity is critical to nitrogen uptake and yield of soybean.