• Korean Journal of Soil Science and Fertilizer
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• v.8 no.3
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• pp.161-170
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• 1975

Status of agriculture in Jeju province were investigated to find out problems and solutions in view of weather, soils and crop productions. Two hundred harmful windy days per year force to build strong wind-break forest near to farm. Somewhat severe drought situation in croping could be completely avoided by good irrigation system using abundant underground water resources. Poor fertility of soils should be improved by using much compost, lime, fused phosphate, and high dose fertilizers. Optimum fertilizer level for each crop should be determined with special consideration on characteristics of volcanic ash soil.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.209-214
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• 2012

This experiment was carried out to investigate the replaceability of chemical fertilizer by SCB liquid fertilizer (SCB) in pear orchard for 5 years. The effects on the mineral content of leaf, fruit quality, yield and soil chemical properties are as follows: The mineral content of leaf showed no difference between the treatments; two SCB liquid fertilizer treatments based on the N (SCB-N) and K (SCB-K) content, and control (chemical fertilizer application). There were no significant differences in yield, titratable acidity and weight of the fruit although the figure of fruit weight was high in SCB-N treatment. Soluble solids content was higher in the SCB treatments than the control. Soil chemical properties such as the content of soil organic matter, available soil phosphate and exchangeable cation were not different, although soil pH was higher in SCB treatments. In conclusion, it is suggest that the use of chemical fertilizer in pear orchard could be replaced by the application of SCB liquid fertilizer because of the same effect on the growth of pear tree and soil chemical properties.

• Korean Journal of Medicinal Crop Science
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• v.11 no.3
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• pp.190-194
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• 2003

A field experiment was conducted to evaluate effect by split-application of slow-release fertilizer on the tea plant. The yield of the 2nd harvested tea leaves was not different to the slow-release fertilizer of two time split manuring had been doing Sep. or Mar. compared with the traditional manuring had been doing four time split manuring, but that of the slow-release fertilizer to one time split manuring in Sep. had decreased $12.5{\pm}1.5%$. In case of the 2nd harvested leave, the contents of chemical components related to quality such as total nitrogen, total amino acid were somewhat higher in the slow-release fertilizer (two time split manuring) than in the traditional manuring, but those of tannin, and caffeine were low, and those of chlorophyll, vitamin C, free sugar and theanine were not different to out of treatments. In scoring test, appearance and quality of green tea were more excellence in the two time split manuring compared with one time split manuring of slow-release fertilizer and with the traditional manuring (four time split manuring). Therefore, I thought that use of slow-release fertilizer be increased yield and quality of tea leaves, and improved efficiency nature of nitrogen, phosphate and potassium out of soil fertilizer components.

• Korean Journal of Organic Agriculture
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• v.5 no.1
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• pp.45-66
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• 1996

In Korea there is still no basic standard for organic agriculture and organic farmers in Korea do not follow the minimum requirements of IFOAM basic standard Most of them just practice the organic agriculture applying organic fertilizer, commercial seed without legume, rotation and green manure. But they believe this system is a absolutely environmental friendly agricultural system and it produce a safe agricultural product since they are not aware of the basic standard of organic agriculture at all. The overuse of organic fertilizer by some organic farmer have caused some severe problems risk for nitrate and phosphate leaching. In soil profile showed the potential risk for nitrate and phosphate leaching. In the paper, it is discussed on the environmental friendly function and the safe vegetable production by european organic agriculture which keeps the internationally recognized basic standards of organic agriculture. Therefore it is strongly recommended that korean organic farmer have to follow the IFOAM it is strongly in order to practice the environmental agriculture and produce the safe food. And it is also necessary to introduce to Korea the basic standard of organic agriculture which coincides with IFOAM's and Codex of FAO/WHO immediately if they really want to practice an organic agriculture in the country.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.210-214
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• 1982

A field experiment to compare the effects of different granular sizes of fused magnesium phosphate (FMP) on the growth and yield of barley plants was conducted on a loam soil during the 1978/1979 cropping period. The results were summarized as follows: 1. No significant differences in yield were observed between the application of comercial FMP, mixture of large and small granules, and small granular FMP; however, the smaller FMP application increased the yield of barley by 5 percent than the larger FMP application. 2. The fresh root weight and the total dry matter were greater in the smaller granular FMP, and the yield showed a linear relationship with the fresh root weight.

• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1132-1137
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• 2003

For the application of environment conscious glass-fertilizer, dissolution characteristics of phosphate glass was investigated. In 0.1K₂O-0.1SiO₂-0.6P₂O/sub 5/ glass system, the compositions were designed according to variation of CaO & MgO contents, and glass formation region was confirmed. From the glass composition, the confirmed glasses were investigated to figure out thermal and dissolution properties. It was detected that glass transition & softening temperature of the glasses increased with increasing MgO contents. The dissolution properties of the glasses was affected by CaO and MgO content ratio.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.326-331
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• 2015

High salinity and sodicity of soils play a negative role in producing crops in reclaimed tidal lands. To evaluate the effects of soil ameliorants on salt removal in a highly saline and sodic soil of reclaimed tidal land, we conducted a column experiment with treating gypsum, compost, and phosphate at 0-2 cm depth and measured the salt concentration of leachate and soil. Electrical conductivity of leachate was $45-48dSm^{-1}$ at 1 pore volume (PV) of water and decreased to less than $3dSm^{-1}$ at 3 PV of water. Gypsum significantly decreased SAR (sodium adsorption ratio) of leachate below 3 at 3 PV of water and soil ESP (exchangeable sodium percentage) below 3% for the whole profile of soil column. Compost significantly decreased ESP of soil at 0-5 cm depth to 5% compared with the control (20%). However, compost affected little the composition of cations below a depth of 5 cm and in leachate compared with control treatment. It was concluded that gypsum was effective in ameliorating reclaimed tidal lands at and below a soil layer receiving gypsum while compost worked only at a soil layer where compost was treated.

• Korean Journal of Environmental Agriculture
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• v.17 no.2
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• pp.182-188
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• 1998

The effect of arbuscular mycorrhizae(AM) on the growth of trifoliate orange seeding were investigated in volcanic ash soil. Trifoliate orange is used as a root stock of citrus in Cheju island. Seedings innoculated with AM fungi were grown for 16 weeks in pots of various levels of fertilizer. Growth characteristics and mineral nutrient contents were measured and spores of AM fungi colonized were identified. Seventy % of the replicsted pots of seedings were colonized by AM in the treatment of high level fertilizer and additional phosphate (40g of 21-17-17 complex fertilizer and 50g of fused phosphate added to 50L of soil). In treatments of low levels fertilizer or without fused phosphate addition, the pots colonized were less than 20 %. Colonization of trifoliate seedings with AM fungi greatly increased the growth of seedings. Shoot length and weight of shoot and root positively regressed on AM colonization ratio. AM colonization caused higher concentrations of P, Cu and Mg in plant, and the relations were significant at 5 % level. Contents of N and Zn in plants also tended to increase, while that of Ca to decrease, with increasing colonization ratio. Four species of AM fungi - Glomus deserticola, G. rubiforme, G. vesiculiferum and Acaulospora sp, - were found in the soil where roots of trifoliate orange as an innoculation materials were collected. All of the 4 species were found in the inoculated pot soils after the seedling growth, indicating that these species can be colonized in trifoliate orange roots.

• Korean Journal of Soil Science and Fertilizer
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• v.5 no.1
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• pp.1-8
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• 1972

In order to expect the effect of silica with large quantity application of current Fused calcium-magnesium phosphate on the paddy rice, there are difficulties of excess phosphorus application because of the high content of phosphate in this fertilizer. This experiment was discussed on the effect of posphate and silica absorbed by rice plant from the low concentrated fused calcium-magnesium phosphate which was fused with mixture of rock phosphate, chemical calcium oxide, magnesium oxide and silicate oxide in the furnace using coke, 1. The fusion material contained 8.9% of citric acid soluble $P_2O_5$ and 33% of soluble $SiO_2$. 2. The rice yields were increased with high significance accompanying the application levels of fused material amounts. 3. No. of grains per head, weight of 1,000 grains and percent of filled grain were caused to increase the productivity of rice plant on account of the high content of silica in straws absorbed from fusion material. The treatment of 300 kg/10a. was the highest yield among the levels of fusion material. 4. At the growing periods of rice plant, amount of absorbed phosphate was higher in the small amount treatment of fusion material until the formation period of young head, and was highest in the treatment of 300 kg/10a. leval among them but slightly desreased at 500 kg/10a. level at the harvest. Amount of absorbed silica was the same trend with phosphorus at the begining of growth period but increased rapidly from the formation period of young head to harvest in the large quantity application levels. 5. Much amount of nutrients were residued in the soil after experiment pacing with application levels. 6. The effect of silica and phosphate on rice plant can be expected with fusion material but it is necessary to decrease the phosphate content on account of the large residue of phosphate in the soil after experiment.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.143-148
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• 2012

Sustainable agriculture requires reliable information on the spatial distribution of the soil chemical properties for effective management of paddy fields. In order to provide adequate soil nutritional information for environmental-friendly agriculture, we investigated the soil chemical properties for 260 paddy soils sampled in Gyeongnam Province from 1999 to 2011 by four years of interval. Soil chemical properties of pH, organic matter, available phosphate and silicate, exchangeable potassium, calcium, and magnesium contents were analyzed. The pH value, organic matter, available phosphate and silicate, and exchangeable calcium and magnesium in paddy soils were significantly elevated in 2011 compared to 1999. The excessive levels of organic matter and available phosphate in paddy soils were detected in 2011. The soil available phosphate was highest in mountain foot-slope (p<0.05) and the soil organic matter was highest in diluvial terrace (p<0.05). It revealed that the soil available phosphate was the responsible factor for the differentiation of soil chemical properties by the topography in paddy soils.