• Proceedings of the Korean Society of Grassland Science Conference
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• 2000.09a
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• pp.106.2-107
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• 2000

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.4
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• pp.342-349
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• 1998

In order to evaluate the effects of nitrogen (N) rate and application method on the recovery of N fertilizer applied in spring and summer by Satsuma mandarins (cv. Miyakawa Wase), N as urea was surface-applied at the rates of 50 (applied with 20 mm water; 50% N application) and 100% (three treatments; applied as solid, with 5 or 20 mm water) of the recommended rate ($150kg\;ha^{-1}\;yr^{-1}$) on 25 March and 12 June with an application ratio of 50 and 20%. The labeled N was applied only once in spring or summer. There were no differences among the four treatments in fruit yield, fruit quality except acid content of juice, and N content of leaves. The recovery of fertilizer N applied in spring by a tree ranged from 7.8 to 8.3% and that of N applied in summer ranged from 11.3 to 14.2% at the three recommended N rates and was 18.0% for the 50% N application. The recovery of fertilizer N applied in spring in the upper 40 cm of soil ranged from 32.1 to 37.7% at the three recommended N rates and was 55.8% at the 50% N application. For N applied in summer, it was 69.8% for surface application of the recommended N rate and ranged from 80.7 to 84.4% for the three N applications with water. The total (tree+soil) recovery of N fertilizer applied in spring was highest (64.1%) for the 50% N application and ranged from 40.3 to 45.5% for the three recommended N rates. The total recovery of N fertilizer applied in summer was also highest (99.4%) for the 50% N application and tended to be higher for the application of N with water than surface application and to increase with increasing irrigation amount of N application.

• Food Science and Preservation
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• v.5 no.3
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• pp.239-246
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• 1998

Polyimide membrane system was designed for manufacturing nitrogen-enriched gas, and basic technical data was suggested for appling this system to controlled atmosphere storage. The permeability characteristics of pure oxygen and nitrogen could be explained by dual-mode sorption model. There was substantial decrease in the permeation rates of oxygen, which is the more permeable gas, through the polyimide membrane due to the presence of nitrogen in comparison with pure oxygen. However, the permeation rates of nitrogen was increased by the presence of oxygen. The ideal separation factor was in the range of 5 to 6 in the range of temperature and pressure difference studied, and the separation factor of air was lower than the ideal separation factor. The increase of ideal separation factor with increasing temperature is due to the fact that the activation energy for oxygen is larger than that for nitrogen. Nitrogen concentration decreased rapidly with increasing product recovery, and it was found that this is a major operating factor to obtain nitrogen concentration required for controlled atmosphere storage. A relation equation, by which nitrogen concentration in storehouse can be predicted, was suggested under the establishment of a hypothetical model for controlled atmosphere storage process using polyimide membrane system.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.387-393
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• 2011

We analyzed the particle size distributions of three commercially available Devarda's alloy (DA) products, tested the nitrate recoveries of each particle size category, and examined the amounts of DA required for 100% recovery by varying $NO_3$-N concentration from 0.5 to 10 mg. We observed that use of DA coarser than 200 mesh resulted in poor analytical recovery (<80%). While the tested alloys were considered to be fine enough (>90% of the particles were less than 100 mesh), the recovery dramatically declined from 80% to 10% in a high concentration range (4 to 10 mg N). Satisfactory recovery was obtained by increasing the amount of finer DA (less than 300 or 450 mesh). However, there was no quantitative relationship between the amount of fine DA and nitrate recovered. Generally, the amount of nitrate reduced per unit DA decreased as the recovery efficiency declined. These results suggest that a sufficient amount of DA must be determined based on particle size distribution, and that treatment of at least two levels of DA and comparison of the subsequent change in nitrate recovery is required for soils containing high levels of nitrate. In addition, further studies are encouraged to account for the observed stoichiometric dis-equivalence of recovered nitrate N per unit mass of DA.

• Journal of Animal Environmental Science
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• v.12 no.2
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• pp.95-100
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• 2006

This study was carried out to develop a continuous process for recovering phosphorus in swine slurry. Magnesium chloride ($MgCl_2$) was used in the test as a magnesium source and the pH was regulated by adding NaOH and aerating. The results showed that the recovery rate of soluble phosphorus (SP) has increased with the molar ratios increased. In case of pH regulated with NaOH, the recovery rates of SP with molar ratio of 1:1.5 were over 95% from both farms. The removal of ammonia-nitrogen was at levels of $4{\sim}9%$. With aeration treatment, the SP recovery rate was 66% and the removal rate of ammonia-nitrogen was 15%. The treatment of NaOH to increase pH showed better SP recovery efficiency than the aeation treatment. However, in case of ammonia-nitrogen removal, the treatment of aeration showed better results than the NaOH treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.143-150
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• 1998

In order to evaluate the nitrogen (N) balance, from the different application methods and levels of $^{15}N$ applied to a satsuma mandarin orchard soils in spring, we surface-applied N as urea at the rates of 50 (water-dissolved), 100 (solid and water-dissolved) and 150% (solid) of the recommended rate ($180kg\;ha^{-1}$) in spring (lebeled N), summer (nonlebeled N) with application ratio of 5:2:3. Fruit yield and quality were not significantly affected by any treatment. Nitrogen contents of spring flush leaves in late August were 3.0% regardless of the treatments. The N recovery by parts of tree itself was in the order of leaves, fruits, roots, stems, and the highest recovery per tree was 22.3% in the 50% recommended water-dissolved surface broadcast while there were not much differences for N recovery (11.9 to 13.6%) among the other three treatments. Total N content in top 30cm of soils was 0.47% regardless of the treatments, but N proportion and total residual N from the fertilizer applied increased with increasing N rate while the N recovery in soils decreased. For the recommended N rate, N proportion and the residual N from the fertilizer applied were greater in the water-dissolved surface broadcast than those in soils surface broadcast. The highest total (tree + soils) N recovery was 70.9% in the 50% recommended water-dissolved surface broadcast, but tended to decrease to 52.2, 46.6, and 43.2% for the recommended water-dissolved surface broadcast, 100 and 150% of the recommended solid surface broadcast, respectively.

• Resources Recycling
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• v.4 no.1
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• pp.25-30
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• 1995

In the preparatIon of reclaimed aluminium lllgot from alumimum scrap, the aluminium recovery was studied a as a function of the preliminary treatment of samples, addition of flux and melting atmosphere. AI dross is produced by an oxidation reaction at the surface of liquid metal. The recovery of AI metal increases u up to maximum 95% by adding salt up to 7%, The recovery of AI metal in the compacted chip bale without oil removal mcrease about 14% compared io non-compacted chip. In the case of the AI seed melting process, the recovery of Al metal of the crushed and compacted chip hale is 97%, In meltmg of alumimum scrap under the atmosphere of carbon and nitrogen gas, the recovery of AI metal increase, but it is decreased when the mixture of salt and carbon powder is added excessively.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.132-139
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• 1999

A field experiment was conducted at Cheju from early March 1998 to early March 1999 to evaluate the effects of foliar applied urea on leaf N content and N recovery in satsuma mandarins (Citrus unshiu Marc.). Seven years old 'Okitsu Wase' trees received foliar spray of urea (22 or 43 g N $tree^{-1}yr^{-1}$) or soil application of urea (86 g N $tree^{-1}yr^{-1}$). 56% of N was applied in spring, 11% in summer and 33% in fall. There were seven trees per N treatment and two trees per N treatment received $^{15}N$-labeled urea in spring and summer to determine N recovery. There were no differences between the treatments for fruit yield and its quality. Nitrogen content of spring flush leaf blades up to early September was greater for trees received foliar spray comparing with soil application but was not greatly affected by any treatment after mid-November. The recovery of fertilizer N in various parts of trees receiving foliar spray of 22 g N $tree^{-1}yr^{-1}$ was greatest, followed by receiving foliar spray of 43 g N and soil application of 86 g N. The recovery of fertilizer N in tree was 29.2 and 17.7% for foliar spray of 22 and 43 g N $tree^{-1}yr^{-1}$, respectively and 8.0% for soil application of 86 g N $tree^{-1}yr^{-1}$. The recovery of fertilizer N in the upper 40 cm of soil was 50.3, 45.6, and 51.8% for foliar spray of 22 and 43 g N $tree^{-1}yr^{-1}$, and soil application of 86 g N $tree^{-1}yr^{-1}$ respectively. The total (tree, fallen leaves, winter weeds, and soil) recovery of fertilizer N was 81.8, 65.1, and 60.6% for foliar spray of 22 and 43 g N $tree^{-1}yr^{-1}$, and soil application of 86 g N $tree^{-1}yr^{-1}$, respectively.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.10b
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• pp.192-193
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• 2005

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.201-208
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• 1994

In order to study the effect of exsisting soil nutritional elements on the nitrogen uptake of sunflower, sorghum and black gram, pot experiment was carried out by using soils sampled from three different depths(0~20, 45~65, 90~110cm) of Brigalow soil in Australia. The results obtained were as follows : Dry matter and nitrogen uptake of corps were increased in the soil with higher nitrogen content. Chlorine uptakes of sunflower and sorghum were increased in the soil with higher nitrogen and lower chlorine contents, but that of black gram was done in the soil with higher contents of both elements. Ratios of nitrogen derived from applied fertilizer of three corps and fixed nitrogen of black gram were relatively low in the soil with higher content of soil nitrogen, but those derived from soil nitrogen were reverse. Recovery rates of applied nitrogen were relatively increased with higher cation uptakes of crops. Chlorine uptakes of sunflower and sorghum were positively correlated with each recovery of nitrogen, but that of black gram didn't show the trend. Recovery rate of applied nitrogen for black gram had significantly negative correlation with increase of soil chloride content.