• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.4
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• pp.383-396
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• 1992

In order to find out the reasons for the excessive accumulation of certain fertilizer elements in arable land in Korea, which may be a detrimental factor for her sustainable agriculture in the future, total requirement of fertilizers were estimated from the huge number of soil test data obtained throughout the country using the fertilizer requirement models based on the soil analysis data and the concepts of multi nutrient factor balance or starter fertiliazer. The total fertilizer requirements estimated based on the present soil fertility status were much less than those estimated from the suspected cropping area of various crops cultivated depending on the conventional fertilizer recommendation for each crops or the actual amount of fertilizer elements consumed through National Agricultural Cooporative Federation(NACF). The excessive accumulation of certain fertilizer elements in arable land in Korea must be due to excessively high dose of chemical fertilizers as well as those farm wastes such as animal wasts produced unexpectedly in large amounts or crop residues. And it is suggested that the improved fertilizer recommendation must be developed in consideration both with the soil fertility status and the amounts of nutrient removal by each crop, and that the high analyzed complex fertilizers commonly used by farmers must ugently be developed in a form containing low P and K with Mg and slow release type N for the better balanced management practices of soil fertility by farmers arid for their practices of sustainable agriculture.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.2
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• pp.100-104
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• 1989

This study was carried out in order to develop a compound fertilizer for raising rice seedling in trays. A compound fertilizer, a trail product, was manufactured using the major fertilizer sources of ammonium sulfate, diammonium phosphate and potassium chloride in combination with zeolite and glutamic acid fermentation waste. Besides, polyacrylamide for slow release control of the fertilzer and Tachigaren and sulfuric acid for reducing the occurrence of seedling rot were used. The component ratios of N, $P_2O_5$ and $K_2O$ of trial product were 4.19, 5.41 and 4.05 percent respectively. The dissolution rate of nitrogen component in water for the trial product with polyacrylamide was lower about fifteen percents than the product without polyacylamide in six hours. Hymexazole, main component of Thachigaren, from the product was released about 86.2 percents in forty eight hours. When the product with polyacylamide applied on red earth soil and paddy soil, the pH of soil ranged from 4.6 to 5.4 for 25 days experiment.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.3
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• pp.296-300
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• 1988

A trial product of monogranular compound fertilizer for sesame under vinyle mulching cultivations was manufactured using the principal sources of urea, diammonium phosphate and muriate of potash in combination with a filler of zeolite and a binder of liquid waste from glutamic acid fermentation. Two field experiments using transparent vinyl mulching for single-crop cultivation and black vinyl mulching for cultivation after wheat and barley cropping were carried out to evalute their effects on sesame and the results obtained were as follows. Plant height and stem diameter of the trial product in sesame plant were higher and better than those of NPK split application and NPK all basic application. As the yield of the trial product was higher and similar to the NPK application plots in transparent and black vinyl mulching treatment respectively, the one time basic application of a developed monogranular compound fertilizer for sesame was possible under vinyl mulching cultivation.

• Asian Journal of Turfgrass Science
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• v.26 no.2
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• pp.135-139
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• 2012

Creeping bentgrass (Agrostis stolonifera) is one of the most popular turfgrasses for high-quality playing surface such as putting green on golf courses and athletic fields. Continues damage such as divot injury on creeping bentgrass is major issue to maintain golf course properly. Although plentiful researches to maximize divot resistance have been reported, minimal research has focused on relation between nitrogen (N) sources and divot resistance. The study was conducted to determine the effect of N source for turfgrass divot recovery and overall tee performance. Eleven fertilizer treatments as N sources were applied to creeping bentgrass 'Penncross'. Before the first application, divot injuries were simulated by removing a core of soil and turfgrass from established plots and backfilling with native soil. Data collection included turfgrass color and quality. N release speed did not influenced divot recovery. Frequency of urea application had no effects on divot recovery. Urea with split application had no difference with no treatment for divot recovery. Polyon product especially polyon mini (41-0-0) had the best performance for divot recovery and for maintaining better turfgrass quality. Overall, small particle size of slow-release N form would influence creeping bentgrasss to recover divot damage.

• Korean Journal of Plant Resources
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• v.28 no.2
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• pp.243-252
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• 2015

This study was performed to establish a production system for in situ and ex situ conservation of Elsholtzia minima Nakai, an endemic plant grown in Jeju Island. Moreover, this study aimed to identify root-growth characteristics according to the use of pre-treatment agents and seedling growth effect according to fertilizer application. The mean temperature was similar in greenhouse and vinyl-moist chamber, but air humidity was higher in vinyl-moist chamber than in greenhouse. After stem planting of Elsholtzia minima Nakai, initial root growth was observed after 10 days in greenhouse and after 7 days in vinyl-moist chamber. Root growth rate was more rapid in vinyl-moist chamber. Moreover, survival rate, root growth rate and root number was slightly higher in vinyl-moist chamber than in greenhouse, indicating that vinyl-moist chamber is more effective in plant growth. When pre-treatment agents were used to remove root growth-inhibiting substances, a higher root growth rate of more than 95% was found in pre-treatment groups, excluding the group treated with AgNO₃ at 77.5%. Thus, Elsholtzia minima Nakai is thought to have less root growth inhibitors. In the analysis of nitrogen application rate and Osmocote application by seedling container, a difference was found in survival rate and growth according to application rate and container conditions. When Osmocote, a slow release fertilizer, was applied to the soil surface around each culture container, survival rate and the growth of aerial and root parts were most favorable. Thus, Osmocote fertilizer is thought to be desirable for seedling propagation of Elsholtzia minima Nakai.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.551-554
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• 2012

The present laboratory investigation was conducted to assess the effect of heavy metals on carbon mineralization. Soil was treated with three concentrations (50, 100 and $150{\mu}mol\;g^{-1}$ soil) of two heavy metals (Cd and Zn) in a factorial combination of treatments replicated four times. Determination of carbon mineralization was carried out at 3, 7, 14, 21, 28, 42 and 56 days after metal treatments.. The amount of $CO_2$-C released from heavy metal treated soils was found to be decreased at an increasing rate during the first 28 days, followed by slow release as incubation progressed. The total amounts of $CO_2$-C released were 448, 382 and $348mg\;kg^{-1}$ soil respectively for soils treated with 50, 100 and $150{\mu}mol\;g^{-1}$ soil of Zn. The corresponding figures for Cd treated soils were 406, 354 and $282mg\;kg^{-1}$ soil implying that dose-dependent reduction in cumulative $CO_2$-C released from soils. The inhibition of carbon mineralization was found to be high in Cd treated soils than that of Zn treated. Therefore, tolerance and adaptation of the microbial community is likely to be related to the concentration and the type of metal. According to the results, carbon mineralization can be considered as possible indicator of soil pollution by means of heavy metals.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.3
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• pp.135-152
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• 1975

The following informations are known from physical and chemical characteristics of orchard soils and nutritional diagnosis of orange leaves in Jeju. 1. Most orange orchards are located on terrace and cindercone thus soil moisture and microclimate of an orchard will greatly be affected by its topography. 2. Excessive well drainage, shallow soil depth, high content of gravels, low solid phase ratio and strong wind will give severe problem of soil moisture and wind errosion, thus the exte- nsion of soil depth is necessary for maintain nutrients, water and sufficient root volume. 3. Available soil water was significantly and positively correlated with organic matter content and clay content also contributes to available soil water. Vinyl mulching was greatly helpful for soil water conservation, wind errosion prevention, soil temperature increases during winter. 4. Abundant amphoteric amorphous allophane take a key role to fix phosphorus and also rations and thus it is the major factor to determine fertilizer efficiency. Lime and phosphorus must be applied in deeper soil layer. Release of filed phosphorus must be reevluated for availability. 5. Organic matter such as see weeds will greatly increase fertilizer efficiency and low fertilizer efficiency during spring may be related to available soil water. 6. Nitrogen was in superoptimum and Mg was enough but P and Ca were somewhat deficient according to leaf analysies while K was deficient according to fruit analysis. Phosphorus application increased sugar/acid ratio and potassium decreases rind percentage. 7. Manganese deficiency and toxicity appeared in a few places. Iron and boron were enough. Most places showed tendency of copper excess but some places showed copper deficiency. 8. Soiling after elimination of rock base, application of slow release fertilizer and abundant organic matter, vinyl mulching and drip irrigation will increase fertilizer efficiency greatly and fruit yield drastically.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.8-14
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• 1996

Use of phosphate coated urea to decrease ammonia volatilization from directly seeded paddy under dryland condition at early stage was tested. Effect on urea hydrolysis was investigated through laboratory study comparing with use of thiourea, a urease inhibitor, under different water content. A field measurement of volitilized ammonia with phosphate-glycerol ammonia absorber was conducted for surface treated urea, phosphate coated urea, phosphate coated slow-release fertilizer and organic fertilizer. Through laboratory study, hydrolysis rate of phosphate coated urea at three days after treatment was lower than that of urea, however, the rate after one week was same. Thiourea addition retarted urea hydrolysis. By field measurement, ammonia volatilization was effectively reduced by use of phosphate coated urea.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.217-222
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• 2010

Bark is a general medium for potted Cymbidium in Korea, but it is difficult to shake off or eliminate the medium from the roots before exporting the potted plants. This working process can injure the roots and then deteriorate plant marketability. This study was carried out to select the optimum medium easier to eliminate from the roots instead of bark and the optimum amount of applied fertilizer to improve the plant growth. Cymbidium young plants 'Honey Hot' and 'Desert Look' were planted in pots with bark, cocochip, and peatmoss. The plants were treated with 2, 4, and 6 g of slow release fertilizer. The plant growth characteristics were investigated in the first and second years during production period of three years. The medium characteristics and mineral nutrient content of the leaves were also examined in the second year. In the first year, the plant growth of 'Desert Look' was improved in all peatmoss treatments more than bark. 'Honey Hot' showed the highest plant growth values in the bark treatment. In the second year, the plant growth of the two cultivars was improved in peatmoss. Cocochip treatments showed the lower plant growth values than bark and peatmoss in the first and second year. There was no significant difference among fertilizer amounts in all the media. The higher CEC values of peatmoss medium resulted to higher capacity to hold more nutrients than bark, and the nutrient retention of the peatmoss improved the plant growth. The higher K and Ca contents in the leaves would contribute to improve the plant growth. Consequently, it would be possible to use peatmoss instead of bark for Cymbidium young plants, but there must be always attention to appropriately water the medium and manage the moisture.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.13
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• pp.107-118
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• 1973

Experiments were carried out to study the effectiveness of METAP as a slow released fertilizer on the growth, grain yield and its components of paddy rice, and to compare its effects with those of single fertilizers in the fields of 3 Crop Experiment Stations and 7 provincial Offices of Rural Development. The effectiveness of METAP seems to be different according to the physical and chemical characteristics of soil, the time of application, climatic conditions, variety and cultural methods. Therefore, the experimental results obtained from the above experiment are summurized as follows: 1. When METAP was applied into sandy soil, grain yield was increased due to increase of the number of panicles, and split application of METAP was more effective than basal only. However, in the reclaimed soil, not heavily percolated soil and fertile soil, no differences were observed between MET AP and single fertilizer applied plot. 2. When a rice variety, 'TONGIL' which is sensitive to the low temperature and produce higher yield in the early transplanting, was not transplanted early and air temperature is relatively lower during the ripening stage, the percentage of ripened grains and 1,000 grains weight were not higher in the METAP applied plots than in the single fertilizer applied plots.