• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.286-296
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• 2007

To increase phosphate (P) availability in soils, the efficiency of silicate (Si) in reducing P adsorption was investigated by competitive adsorption tests under changing conditions of pH, ion concentrations, and order of anion addition along with single adsorption properties of each ion at $20^{\circ}C$. In the single ion adsorption study, P and Si ions showed the opposite reaction patterns: phosphate adsorption decreased with increasing pH and attained adsorption maximum however, silicate adsorption increased with increasing pH without attaining adsorption maximum. Phosphorus and Si adsorption were influenced by pH in the range of 5.0 - 9.0 and the type and amount of P and Si concentration. Silicate added to soil before P or in a mixture with P significantly reduced P adsorption above pH 7.0; however, there was no significant Si-induced decreased in P adsorption at pH 5.0 when anions were added as mixture. The efficiency of Si in reducing P adsorption increased with increasing Si concentration and pH. The effect of P on Si adsorption was relatively small at pH 5.0 and no effect of P on silicate adsorption was observed at pH 9.0. The presence of Si strongly depressed P adsorption when Si was added before P compared to P and Si added as a mixture. These results suggest that application of Si may decrease P adsorption and increase the availability of P in soils. Furthermore, a Si source would be better to add before P application to enhance the availability of P in soils.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.241-248
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• 2009

A farming area located near an abandoned copper mine in GuPo-ri, Choongchung province is heavily contaminated with heavy metals such as As, Pb, Cd, Cu and Zn of which concentrations are higher than the values typically detected in Korean soil environment. In this work, laboratory and field studies were conducted to examine feasibility of using Ca-citrate-phosphate solution in stabilizing heavy metals in the polluted soils. In laboratory batch experiments with field soil, the addition of Ca-citrate-phosphate solution resulted in decrease of aqueous phase concentration of phosphate and improvement of heavy metal stabilization, compared to those for sterilized soil samples. This indicates that microbial uptake of phosphate may have provided positive effects on availability of phosphate toward heavy metal stabilization. According to microbial community analysis for the field experiment, the use of Ca-citrate-phosphate led to increased diversity of microbial populations, and strict anaerobic microorganisms such as Anaerofilum and Treponema became the most dominant populations in the solution-amended field experiments. These findings suggest that, when Ca-citrate-phosphate is used for heavy metal stabilization in soils, microbial processes may have important roles in improving the stabilization of heavy metals by providing reducing conditions to the treatment locations or/and by making phosphate available to heavy metal stabilization.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.325-332
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• 1983

To investigate interactions of silicate and phosphate applied in paddy soil, different levels of the two fertilizers were treated on pots of Jinheung variety of Japonica rice, then availability and absorption of the silicate and phosphate and growth of the rice plant were analyzed. The availability of silicate applied in soil was reduced by increased application of phosphate and this antagonism implied the interaction of silicate and phosphate in soil. The silicate absorption by rice plants was remarkably reduced by the phosphate application, while the phosphate absorption was reduce only at high levels of silicate. At low levels of silicate, the phosphate absorption was affected differently depending on growth stage or parts of the rice plant. The application of silicate fertilizers increased the pH of the soils. The application of silicate and phosphate fertilizers improved the plant height, the tiller number, and the grain weight, but not the dry weight of the grain. The effect of interaction of silicate and phosphate on the plant growth did not appeared.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.4
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• pp.281-286
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• 1990

Field experiments were conducted to avail the accumulated phosphorus by silica 200kg/10a and compost 2,000kg/10a instead of phosphate fertilization in 1988 to 1989. Cultivated varieties were Dongjinbyeo in paddy soils of Av. $P_2O_5$ 233ppm, and Baegunkong in upland soils of Av. $P_2O_5$ 530ppm. The results were as follows. 1. Available phosphorus in the soil was increased about 60ppm in silica and compost application compared with control. Its increment rate by silica and compost application was higher in paddy soils than in upland soils. 2. Absorbed phosphorus by plant was increased in silica and compost application compared with control, whose difference was higher in soybean plant than in rice plant. 3. Amount of absorbed phosphorus in plant was negative in relation to soil DTPA-Fe, but was positive in relation to soil reduction and root nodule of soybean. 4. Persistence rate of phosphorus was about 80 percent in compost application and 100 percent in phosphate fertilization compared with control, and it was apt to decrease by silica. 5. The yield of rice was no difference between with and without phosphate fertilization, but the yield of soybean was increased 5 percent in none application compared with phosphate fertilization.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.949-954
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• 2012

This study is conducted to evaluate the effects of chelating agents for improving plant growth and reusing accumulated nutrients in soils of plastic film house. Two experiments were carried out at follows: i) The incubation test was conducted using soils treated with 0, 300 mM of EDTA and DTPA to examine the availability of nutrients. ii) For the pot test, chinese cabbages were cultivated in soils with 0, 0.1, 0.5, 1, and 5 mM of EDTA and DTPA to examine the impacts of plant growth response. The application of chelating agents increased ther availability of soil nutrients in the following order: DTPA > EDTA > control. Inorganic concentration of chinese cabbages in DTPA treatments consderably increased in nitrogen, phosphate, iron and aluminium contents than that of the other treatments. The optimal concentration of DTPA for vigorous plant growth as 0.5 mM. Thus, DTPA was more effective than other chelating agents for healty growth of cabbages and the availability of nutrients accumulated in plastic film house.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.49-54
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• 2007

This study was conducted to determine effects of composted livestock manure application on soil nutrient change. PVC pot $(30\times100cm)$ was filled with either volcanic ash soil (Gujwa series) or non-volcanic ash soil (Aewol series) and the 20 cm surface soils were applied with composted livestock manures of cattle pig and poultry at the rates of 0, 50, 100 and 150 ton/ha, respectively. After 210 days soils samples of phosphate, potassium, calcium, and magnesium affected by application of the compost. The applied composted were equivalent to the application of organic matter of $23\sim111$ ton/ha and nitrogen of $80\sim450$ ton/ha. Availability rate of phosphate after the application of composted livestock manures ranged from 1.6 to 91.7% according to the different composted. It was much higher in the non-volcanic ash soil than in the volcanic ash soil. Availability rate of potassium fractional recovery rate change ranged from 22 to 94% according to the different manures. It was larger in the composted Availability rate of calcium 38 to 93% and $9\sim90%$ in volcanic ash soil and non-volcanic ash soil, respectively, It was higher in the composted manures followed by cattle and composted pig manures. Availability rate magnesium ranged from 12 to 41% and $1\sim9%$ in volcanic ash soil and non-volcanic ash soil, respectively. The rate was higher in the composted poultry manure followed by pig and composted cattle manures.

• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.197-202
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• 2003

Phosphorus is one of the major plant growth limiting nutrients, despite being abundant in soils in both inorganic and organic forms. Phosphobioinoculants in the form of microorganisms can help in increasing the availability of accumulated phosphates for plant growth by solubilization. Penicillium oxalicum CBPSTsa, isolated from paddy rhizosphere, was studied for its phosphate solubilization. The influence of various carbon sources like glucose, sucrose, mannitol and sorbitol and nitrogen sources like arginine, sodium nitrate, potassium nitrate, ammonium chloride and ammonium sulphate were evaluated using liquid media with tricalcium phosphate (Ca-P), ferric phosphate (Fe-P) and aluminium phosphate (Al-P). Maximum soluble phosphate of 824 mg/L was found in the amendment of sucrose-sodium nitrate from 5 g/L of Ca-P. Mannitol, sorbitol, and ariginine were poor in phosphate solubilization. While sucrose was better carbon source in solubilization of Ca-P and Al-P, glucose fared better in solubilization of Fe-P. Though all the nitrogen sources enhanced P solubilization, nitrates were better than ammonium In the amendments of ammonium chloride and ammonium sulphate, higher uptake of available phosphates by the fungus was found, and this resulted in depletion of available P in Fe-P amendment Phosphate solubilization was accompanied by acidification of the media, and the highest pH decrease was observed in glucose amendment Among the nitrogen sources, ammonium chloride favored greater pH decrease.

• Korean Journal of Environmental Agriculture
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• v.23 no.3
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• pp.133-137
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• 2004

Recently, saw dust manure has been widely used in horticultural crop production in Korea. Animal manure is produced by decaying of livestock manure mixed with saw dust, and contained higher nutrients and ion concentration than the traditional manure made from rice straw and grasses. Therefore, a continuous application of the animal manure disregarding to soil characteristics may be ruined the soil conditions. This study was conducted to investigate the transportation of the nitrogen, phosphate, potassium, and ion concentration of the animal manure applied to volcanic and non-volcanic soils in Jeju islana Soil chemical analysis were done before and 180 days after animal manure application. After animal manure application, $NO_3$-N moved up to 90cm in volcanic soil, while the movement was limited to 60 cm in non-volcanic soil. Phosphate concentration was high up to 30 cm, where crop roots are mainly distributed, in volcanic soil, however, the phosphate moved up to 60 cm in volcanic soil. Exchangeable potassium moved up to 90 cm in volcanic soil, but the movement wns limited up to 60 cm in non-volcanic soil. For both soil types, no significant different in ion concentrations was observed up to 60 cm in soil depth, though the concentrations were higher in volcanic ash soils as compared to the non-volcanic ash soils.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.3
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• pp.162-165
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• 1982

As an approach to the explanation of increased availability of phosphate in reduced wetland soils, the interrelationships among pH, pe, $Fe^{+{+}}$ and water soluble phosphate in reduced soil-water suspension was studied. 1. p.e value of soil incubated for 8 weeks at $30^{\circ}C$ under waterlogged condition was sufficiently low to allow the conversion of strengite to vivianite. 2. The concentration of water soluble $Fe^{+{+}}$ in this system was higher than that is allowable by the solubility of vivianite. 3. From the relationship between pH and the concentration of water soluble $Fe^{+{+}}$, the concentration of water soluble $Fe^{+{+}}$ could be determined with the solubility of $FeCO_3$. 4. No definite relationship between pH and water soluble P was recognized which implied that the concentration of water soluble P in this system could not determined with the solubility of vivianite.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.173-180
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• 1996

Effects of inoculation with phosphate-solubilizing microorganisms, Pseudomonas putida and Aspergillus niger, were studied in both acidic red-yellow and alkaline calcareous soils cropped with pimiento. In red-yellow soil after cultivation, the amounts of soil available phosphorus on non-fertilizer and fertilizer plots inoculated with Aspergillus niger, and on rice straw plot inoculated with Pseudomonas putida and Aspergillus niger were significantly higher than uninoculation treatments, but there were no differences in calcareous soil. With inoculation of either Pseudomonas putida or Aspergillus niger, increase in phosphorous uptake by pimiento cultivated in calcareous soil was detected on non-fertilizer, and fertilizer plots except rice straw plot. Although there were no significant differences in soil cellulase activities among treatments, the activity was the highest on rice straw plot in red-yellow soil. The phosphatase activities in red-yellow soil were increased by the inoculation with Aspergillus niger only, and the activity in calcareous soil was improved by the inoculation with either Pseudomonas putida or Aspergillus niger.