• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.110-134
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• 1977

Effects of phosphorus, potassium and calcium applications on root activity and agronomic characters of paddy rice were studied in submerged paddy soil on which starch was applied to accelerate soil reduction and production of toxic substance during 1971～1973. Root activity at heading date was decreased in reduction accelerated soil by starch application. Effect of calcium application on root activity was differed along soil conditions, phosphorus or potassium levels. Single effects of phosphorus or potassium application were not significant on every observed characters. Calcium application when phosphorus or potassium was not used as basal but used as top dressing increased yield and yield components, especially filled grain ratio. Effect of calcium application along soil conditions was differed on agronomic characters, but calcium application with phosphorus or potassium was more effective to increase yield components and grain yield. Sufficient application of phosphorus, potassium and calcium could improve the nutritional situation of rice plant for panicle development and grain maturity in reduction accelerated paddy soil in which poor growing of rice plant after panicle formation is anticipated by the production of toxic substance from soil.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.4
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• pp.268-275
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• 2013

To evaluate the effects of submerged aerators installed at Chudong and Muneui areas in Daechung Reservoir on improvement of water quality and reduction of algal bloom, the water quality was monitored at the effected and control areas at the time of operation. The water temperature and concentrations of dissolved oxygen, total phosphorus, and total nitrogen in depth at the effected and control areas were not different each other, indicating the submerged aerators at these areas are not effective for circulation of water body and reduction of nutrients. In warmer season, the concentrations of total phosphorus in deep water, which was probably released from contaminated sediment or inflowed from watershed, was high. To decide the operation of aerators in this season, the concentration of total phosphorus in water should be considered because the dispersed phosphorus by operation of aerators can enhance the algal growth.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.2
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• pp.120-126
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• 2022

The objective of this study was to determine effects of phosphorus on lignification and carbohydrate metabolism in Kentucky bluegrass under drought stress. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (PO₄^3-; P) or potassium phosphonate (PO₃^3-; PA) in drought-stressed plants. Drought had significant negative effects on plant growth, as revealed by reduced biomass of shoot. Drought-induced increase of lignin content was concomitant with the increase of phenylalanine ammonia-lyase (PAL). Soluble sugar content was highly increased but fructan content was largely decreased by drought stress. However, the application of phosphorus was efficient to ameliorate the adverse effects of drought. PA application improved reduced shoot growth and relative water content, and inhibited lignification synthesis with a reduction of PAL activity. P or PA application maintained soluble sugar and fructan content at similar levels to controls under drought stress. These results indicate that phosphorus application may mitigate the drought stress by inhibiting the lignification and promoting the fructan assimilation.

• 한국환경농학회:학술대회논문집
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• 2009.07a
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• pp.350-351
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• 2009

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.12
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• pp.1743-1749
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• 2000

An experiment was conducted to investigate the effect of supplementation of commercial phytase and ${\beta}-glucanase$ to wheat-soybean meal based layer diets. Control (17% CP) and reduced protein (13.5% CP) diets were compared with and without phytase and/or ${\beta}-glucanase$. Reducing dietary crude protein levels reduced the amount of N excreted by laying hens with no adverse affect on egg production or overall feed conversion ratio. There was, however, a slight reduction in average egg weight. When phytase was added to the control protein diets it was possible to reduce the level of dicalcium phosphate in the diet without a loss in performance and daily P output was reduced significantly. When phytase was added to the reduced protein diets, however, there was a dramatic loss in performance in the last four weeks of the study. Supplementation of ${\beta}-glucanase$ to wheat based layer diet did not appear to have beneficial affects in terms of laying performance and reducing nitrogen or phosphorus excretion. Combination of phytase and ${\beta}-glucanase$ had no positive effects on laying performance or reduction of DM, N and P.

• Journal of Korean Society on Water Environment
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• v.33 no.4
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• pp.387-393
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• 2017

A chemical batch tests were conducted to evaluate if microwave heating enhances phosphorous release from waste activated sludge (WAS) at pH 2.5, 5, 7, 9 and 11. Polyphosphate-accumulating organisms have a unique physiological feature, which releases intracellular polyphosphate granules when they are exposed under high temperature environments. Microwave irradiation was found to encourage large amount of phosphorus release from WAS, depending on pH and temperature conditions. Most of phosphorus was released below $59^{\circ}C$ within 30 min. A marked increase in phosphorus release was observed under alkaline or acidic conditions. However, based on control tests for phosphorus release under different pH conditions without microwave heating, the largest amount of phosphorus released by microwave irradiation was found at pH 7, followed by 5, 9, 11. On the other hand, crystallization was conducted to obtain magnesium ammonium phosphate (MAP) from phosphate released by microwave heating at pH 7. X-ray diffraction analysis confirmed that the recovered crystalline materials were MAP. MAP is an environmentally friendly fertilizer, which slowly releases ammonia and phosphorus in response to the demand of plant root. Thus, the recovered MAP as a phosphate fertilizer is fully expected to play a important role in the reduction of agricultural non-point pollution.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.4
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• pp.59-65
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• 2011

The purpose of this study was to analyze the water quality change when wastewater applied to study paddy fields. CREAMS-PADDY (Chemical, Runoff and Erosion from Agricultural Management System) model was used to estimate the field-scale water quality. Simulated results were compared with observed data monitored from Byeongjeom study paddy fields which is located near the Suwon sewage treatment plant in Gyeonggi-do. Significance analysis was performed for the three different irrigation water quality level and five fertilizer reduction scenarios using LSD (Least Significant Difference) and DMRT (Duncan's Multiple Range Test). Total nitrogen was found to be significant for both irrigation water quality level and fertilizer reduction while total phosphorus was not. Annual drainage load for total nitrogen was reduced by 66~92 % compared to irrigation load when treated wastewater irrigated to study paddy fields from 2002 to 2007. Total phosphorus was reduced by 70~86 %.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.134-138
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• 1997

The objective of this study was to examine the effect of phosphorus deficiency on nitrogen fixation and photosynthesis of nitrogen fixing soybean plant under $CO_2$ enrichment condition. The soybean plants(Glycine max [L.] Merr.) inoculated with Bradyrhizobium japonicum MN 110 were grown with P-stressed(0.05 mM-P) and control(1 mM-P) treatment under control$(400\;{\mu}l/L\;CO_2)$ and enrichment$(800\;{\mu}l/L\;CO_2)$ enviromental condition in the phytotron equipped with high density lamp$(1000\;{\mu}Em^{-2}S^{-1})$ and $28/22^{\circ}C$ temperature cycle for 35 days after transplanting(DAT). At 35 DAT, phosphorus deficiency decreased total dry mass by 64% in $CO_2$ enrichment condition, and 51% in control $CO_2$ condition. Total leaf area was reduced significantly by phosphorus deficiency in control and enriched $CO_2$ condition but specific leaf weight was increased by P deficiency. Phosphorus deficiency significantly reduced photosynthetic rate(carbon exchange rate) and internal $CO_2$ concentration in leaf in both $CO_2$ treatments, but the degree of stress was more severe under $CO_2$ enrichment condition than under control $CO_2$ environmental condition. In phosphorus sufficient plants, $CO_2$ enrichment increased nodule fresh weight and total nitrogenase activity(acetylene reduction) of nodule by 30% and 41% respectively, but specific nitrogenase activity of nodule and nodule fresh weight was not affected by $CO_2$ enrichment in phosphorus deficient plant at 35 DAT. Total nitrogen concentrations in stem, root and nodule tissue were significantly higher in phosphorus sufficient plant grown under $CO_2$ enrichment, but nitrogen concentration in leaf was reduced by 30% under $CO_2$ enrichment. These results indicate that increasing $CO_2$ concentration does not affect plant growth under phosphorus deficient condition and phosphorus stress might inhibit carbohydrate utilization in whole plant and that $CO_2$ enrichment could not increase nodule formation and functioning under phosphorus deficient conditions and phosphorus has more important roles in nodule growth and functioning under $CO_2$ enrichment environments than under ambient condition.

• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.1-6
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• 2016

In this year, Koreans have a shortage in agricultural and drinking water due to severe algal blooms generated in major lakes. Waste oyster shells were obtained from temporary storage near the workplace at which oysters were separated from their shells. Heating ($1000^{\circ}C$ for 1 h in air) was employed to convert raw oyster shell powders into calcium oxide powders that reacted efficiently with phosphorus and nitrogen to remove algal blooms from eutrophicated wastewater. As the dispersed amount of heated oyster shell powders was increased, water clarity and visual light penetration were improved. Coagulation, precipitation and carbonation process of the heated oyster shell powders in a water purifier facilitated removal of eutrophication nutrient such as phosphorus and nitrogen, which is both beneficial and economically viable. $CO_2$ implantation by carbonation treatment not only produced thermodynamically stable CaO in oyster shells to derive precipitated calcium carbonate (PCC) but also accelerated algal removal by activation of coagulation and precipitation process. The use of oyster shell powders led to a mean reduction of 97% in total phosphate (T-P), a mean reduction of 91% in total nitrogen (T-N) and a maximum reduction of 51% in chemical oxygen demand (COD), compared with the total pollutant load of raw algal solution. Remarkable water quality improvement of algal removal by heated oyster shell powders and PCC carbonation treatment will allow utilization as water resources to agricultural or industrial use.

• Journal of Life Science
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• v.20 no.10
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• pp.1468-1475
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• 2010

Sulfate reduction rates (SRR) using $^{35}SO_4^{-2}$, sulfide producing rates (SPR) using gas chromatography, the number of sulfate reducing bacteria (SRB) using the most probable number (MPN) method, and soil components (moisture, ammonium, total nitrogen, total organic carbon, total carbon, total inorganic phosphorus, total phosphorus, and sulfate) using standard methods in the organic/conventional rice paddy soils, cleaned/polluted reservoir soils, and cleaned/polluted foreshore soils were studied with the change of seasons. The average SRR was more related to the number of SRB and soil components (especially nitrogen and phosphorus) than sulfate concentration. SRR was also recorded to be highest in October soil samples. However, SPR was higher in foreshore soils containing a high concentration sulfate than in fresh water soils, and it was also recorded to be higher in the polluted areas than in clean areas. From these results, we can conclude that the SRR and SPR of anaerobic environments were affected by the number of SRB, soil components and temperature.