• Korean Journal of Soil Science and Fertilizer
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• v.15 no.1
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• pp.16-33
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• 1982

The major problems of chemical fertilizer supply and consumption involved in price policies since the end of World War II in Korea and their solutions were extensively discussed. The period was divided into three sub-periods: 1946-1960, 1961-1967 and 1968 to present. Since 1968 when the operations of three large-scaled fertilizer plants: Yongnam Chemical Co., Chinhae Chemical Co. and Hankuk Fertilizer Co. were begun in full scale, the domestic supply of nitrogen and phosphate fertilizers were almost enough for the domestic demand. However, since 1976, when Namhae Chemical Co. was added to the production capacity, the fertilizer industry has been faced with the overproduction problem of nitrogen, and the high production cost due to high petroleum price, which gave financial difficulties. Several policy directions and alternative measures for solving the current problems were also suggested in this presentation.

• Journal of Sericultural and Entomological Science
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• v.35 no.1
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• pp.11-16
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• 1993

Field experiment and silkworm rearing were conducted for 4years in an attempt to reduce phosphorus fertilizer in mulberry field with high levels of phosphate. Experiments consisted of four treatments; normal recommended P application(13kg P2O5/10a), half, null and no fertilizer on each of 3 mulberry fields, two fields with 300ppm and one filed begining with 450ppm of aviable P2O5 content in soil. One of 300ppm fields was used for leaf quantity and one for leaf quality test by silkworm rearing. Leaf yield in the 300ppm field decreased after the 3rd spring in the no phosphorus treatment and in the 4th fall in the half phosphorus treatment. No yield decrease occurred in 450ppm field for 4 years. Yield decrease did occur in the next rearing season after soil phosphate content in the 10~20cm zone dropped below 150ppm. Phosphorus fertilizer should be applied at this time. Though P2O5 concentration in leaves of no phosphorus treatment was 0.18% lower that that of conventional treatment, there were no difference in cocoon quality.

• Journal of Korean Society on Water Environment
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• v.32 no.4
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• pp.343-348
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• 2016

A chemical sequencing batch reactor was operated to test the feasibility of nutrient recovery from a biological livestock wastewater treatment plant. Both phosphate and ammonia could be successfully recovered as magnesium ammonium phosphate (MAP) crystals. The contents of TP and TN in the recovered MAP crystals were 26.2% and 4.0%, respectively. Zn, Cr and Ti were identified in the crystals, but the contents remained below the Korean standard for an organic fertilizer. Chemical analyses confirmed that the MAP crystals could be useful phosphate fertilizers. On the other hand, the results of physical analyses using an X-ray diffractometer and an energy dispersive X-ray spectrometer strongly suggested that crystalline materials like magnesium potassium phosphate (KMP) and hydroxyapatite (HAP) were also formed during the MAP crystallization, depending on the availability of K⁺ and Ca²⁺.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.494-501
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• 2013

Two phosphate solubilizing Pantoea strains (P. agglomerans and P. rodasii) were employed in elucidating their phosphate solubilizing potential under different carbon and nitrogen sources, pH, temperature and salt conditions. Plant growth promoting characteristics such as ACC deaminase activity, indole acetic acid (IAA), HCN, ammonia, and siderophore production of the two strains were assessed in vitro. Potential applicability of the strains as bio-inoculants was also evaluated in pot experiments conducted under green house conditions. Phosphate solubilization measured as the amount of phosphorous released into the medium was recorded as 810 and $788{\mu}g\;ml^{-1}$ respectively by P. agglomerans and P. rodasii. Glucose at the rate of 2% was found be the best carbon source, while $(NH_4)_2SO_4$ was the best nitrogen source for both strains. Despite a slight decrease in phosphate solubilization observed at higher temperature, pH and salt concentrations, both strains could withstand against a range of temperature ($30-35^{\circ}C$), pH (7-9) and the presence of NaCl (up to 5%) without much compromising the phosphate solubilization. Different plant growth promoting traits (ACC deaminase activity, IAA, HCN, ammonia, and siderophore production) of the strains and their ability to promote the growth of green gram seedlings indicate that both strains possess high potential to be used as bio-inoculants.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.268-273
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• 1999

To measure the precision of Soiltek$^{(R)}$ KA-1 spectrophotometric measurement of soil available phosphate, standard deviation, C;V, and relative sensitivity were investigated, comparing to Lancaster method. Available phosphate concentration measured by Soiltek$^{(R)}$ KA-1 spectrophotometric method was highly correlated with Lancaster method($r=0.998^{***}$) and the slop of regression equation was close to 1.0. There were no differences in standard deviation. CV, and relative sensitivity for soil available phosphate concentrations measured by two methods. Regarding to convenience of experimental procedure and instrumental operation, and time saving analysis, Soiltek$^{(R)}$ KA-1 spectrophotometric measurement for soil available phosphate is highly recommended.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.118-126
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• 2020

Silicon and phosphorus are elements that are beneficial for plant growth. Despite the abundant availability of silicate and phosphate in the Earth's crust, crop nutritional requirements for silicon and phosphorus are normally met through the application of fertilizer. However, fertilizers are one of the major causes of heavy metal pollution. In our study, we aimed to assess silicate and phosphate solubilization by the bacteria Enterobacter ludwigii GAK2, in the presence and absence of phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), to counteract cadmium stress in rice (Oryza sativa L). Our results showed that the GAK2-treated rice plants, grown in soil amended with phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), had significantly reduced cadmium content, and enhanced plant growth promoting characteristics including fresh shoot and root weight, plant height, and chlorophyll content. These plants showed significant downregulation of the cadmium transporter gene, OsHMA2, and upregulation of the silicon carrier gene, OsLsi1. Moreover, jasmonic acid levels were significantly reduced in the GAK2-inoculated plants, and this was further supported by the downregulation of the jasmonic acid related gene, OsJAZ1. These results indicate that Enterobacter ludwigii GAK2 can be used as a silicon and phosphorus bio-fertilizer, which solubilizes insoluble silicate and phosphate, and mitigates heavy metal toxicity in crops.

• Korean Journal of Soil Science and Fertilizer
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• v.5 no.2
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• pp.53-57
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• 1972

In order to obtain some informations on the improvement of fertility of poor red yellow soils widely distributed in hilly lands of Korean peninsula, a pot culture study was made with a hill land soil in comparison with a fertile soil commonly used for vegetables. The results are as follows; 1. In addition to the normal application of phosphate, the mixing of a large dose of fused phosphate with whole soil increased the yeild of chinese cabbage remarkably, having the promotion particulary of the available phosphate level in the acidic low fertility soil. At the sometime the mixing seemed to short down the period of soil maturing to fertile for good crop. It is, however, considered that such effect of fused phosphate must also be evaluated economically through a long term experiment. 2. A relatively close relationship between the soil phosphate soluble in dilute acid and chinese cabbage growth was observed.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.442-446
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• 2007

From the rhizoplane and rhizosphere of pepper, tomato, lettuce, pasture, and grass, unsoluble inorganic phosphate solubilizing bacterial strains were isolated using plate base assay on Pikovskaya's medium. Two strains, CL-1 and CL-2, which produced largest halo on plates (indicative of phosphate solubilization)were selected for further studies. Based on these biochemical and 16S rRNA analysis strains CL-1, CL-2 were found to be as species of Pseudomonas sp. and Kluyvera sp., respectively. In broth assay Pseudomonas sp. CL-1 and Kluyvera sp. CL-2 solubilized insoluble phosphate by 193.4 mg and $493.6P\;mg\;L^{-1}$, respectively after $3^{rd}$ day inoculation. These effecient phosphate solubilizing bacteria have a potential to be developed as microbial based fertilizer in future.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.195-200
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• 1982

Fused phosphate and slag have used as a sources of phosphate and silicate fertilizers. In order to find out effects of these fertilizers on the growth of young rice plants in nursery, relationships between dry matter production and nutrient uptake at different fertilizer application rates were investigated for two rice varieties, Milyang 23 (a Indica-Japonica hybrid) and Akibare (a Japonica). The results were summarized as followers; 1. The maximum dry matter production was obtained at 75-150 kg/10a of fused phospate and 100-200 kg/10a of slag, respectively, however, a some variations between varieties were recognized. 2. The top/root ratio of varieties around 1.0 was proper for healty see dings and this ratio was reached at application of 75 kg/10a of fused phosphate and 200 kg/10a of slag. 3. The efficiency of applied silicate of rice seedlings was higher in fused phosphate than in slag. 4. The growth of seedling was severely retarded when soil pH was increased above 7 by the application of more than 225 kg/10a of fused phospahte and 400 kg/10a of slag.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.773-778
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• 2011

Long-term continuous application of livestock by-products to agricultural land may adversely affect the soil characteristics and the crop yield. Five year term study from 2007 was carried out to assess the effects of repeated application of low-concentration swine slurry on soil chemical properties including phosphate and heavy metal contents and yield of tomato (Lycopersicon esculentum) and cucumber (Cucumis sativus L.) in a greenhouse. Treatments were conventional chemical fertilizers and three application rates of low-concentration swine slurry (Slurry composting and biofiltration, SCB): 50%, 100%, and 200% of recommended nitrogen fertilization. For swine slurry treatment of 50% nitrogen, deficient nitrogen was supplemented with urea fertilizer. The soil phosphorus and heavy metal contents after five year continuous application of swine slurry were not significantly higher than those of chemical fertilizer use. Repeated application of the swine slurry alone for five years resulted in relatively high soil exchangeable potassium and sodium compared with chemical fertilizer treatment. Contents of heavy metals in leaves of tomato and cucumber did not show significant difference among treatments. Yields of the crops for the swine slurry were not significantly different from that of chemical fertilizer. The results imply that continuous application of the swine slurry may not influence levels of soil phosphate and trace elements in greenhouse soils but could accumulate potassium and sodium in the soil.