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Korean Journal of Environmental Agriculture

p-ISSN 1225-3537
e-ISSN 2233-4173

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The Korean Journal of Environmental Agriculture is an official publication of the Korean Society of Environmental Agriculture. It is published quarterly a year, March 31, June 30, September 30, and December 31, and distributed to more than 700 members including individuals and institutions. The abbreviated title is ‘Korean J. Environ. Agric.’ The journal was launched on June 30 in 1982, the Print ISSN was issued on October 30, 1992 (Volume 11, No. 2) while the Online ISSN was issued on December 31, 2010 (Volume 29, No. 4). Whole document of a part of the articles in this journal are listed in the Google Scholar, Korea Citation Index (KCI) and ScienceCentral. The full text is freely available from http://www.korseaj.org.

Creative Commons Attribution Non-Commercial License

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Current Issue 2017. Vol.36, Iss.3more..

  • Change in Available Phosphate by Application of Phosphate Fertilizer in Long-term Fertilization Experiment for Paddy Soil
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    BACKGROUND:

    Phosphorus(P) is a vital factor for rice but excess input of phosphorus fertilizer can cause environmental risk and waste of fertilizer resources. We studied to assess the change of available phosphate, P balance, critical concentration of available phosphate under a rice single system.

    METHODS AND RESULTS:

    The changes of available phosphate of paddy soil were examined from long-term fertilization experiment which was started in 1954 at the National Academy ofAgricultural Science. The treatments were no phosphate fertilization(No fert., andN), phosphate fertilization(NPK, NPKC, and NPKCLS). The available phosphorus concentrations in treatmentswithout phosphate fertilizer (No fert. andN)were decreased continuously. But, after 47 years, available phosphate content in phosphate fertilizer treatment (NPK,NPKC, andNPKCLS) reached at the highest (245~331 mg kg-1), showing a tendency to decrease afterward. The mean annual P field balance in these treatments (NPK,NPKC, andNPKCLS) had positive values that varied from16.6 to 17.5 kg ha-1 year-1, and ratio of residual P were increased. These showed that phosphate fertilizer in soil were converted into the form of residual phosphorus which was not easily extracted by available phosphate extractant. Also, Itwas estimated that the critical value of available phosphate for rice cultivationwas 120mg kg-1 using Cate-Nelson equation.

    CONCLUSION:

    We concluded that no more phosphate fertilizer should be applied in rice single system if soil available phosphate is higher than the critical P value.

  • Nutrient Leaching and Crop Uptake in Weighing Lysimeter Planted with Soybean as Affected by Water Management
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    BACKGROUND:

    Soil water content strongly depends on weather condition and irrigation, and it could influence on crop nutrient use efficiency. This study was performed to assess nutrient uptake of soybean by soil water condition.

    METHODS AND RESULTS:

    In this study, nutrient leaching and crop uptake as affacted bywatermanagement practice was investigated using weighing lysimeter which is located in National institute of agricultural science, Wanju, Jeonbuk province fromJune 2015 toOctober 2016. Water supply for soybean (cv. Daewon)wasmanagedwith irrigation and rainfall. Nitrate leaching was greatest in the rainfall treatment at early July 2016.Yield of soybean in the rainfall treatment was only 25%compared to the irrigation due to the drought at flowering and podding period. The uptake of nitrogen was considerably reduced by drought whereas the uptake of phosphorus and potassium was less affected by drought.

    CONCLUSION:

    It was proven that nitrogen loss and uptake were dependent on soil water condition. Therefore, irrigation water management to maintain available soil moisture capacity is critical to nitrogen uptake and yield of soybean.

  • Simultaneous Determination and Monitoring of Bisphenols in River Water using Gas Chromatography-Mass Spectrometry
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    BACKGROUND:

    This studywas carried out to establish an efficient sample preparation for the simultaneous determination of bisphenols (BPs) in river water samples using gas chromatography-mass spectrometry (GC-MS). Sample preparation was examined with conventional extraction methods, such as solid-phase extraction (SPE) and liquid-liquid extraction (LLE), and their efficiencywas compared with validation results, including linearity of calibration curve, method detection limit (MDL), limit of quantification (LOQ), accuracy, and precision.

    METHODSANDRESULTS:

    TheBPs (bisphenolA, BPA; bisphenol B, BPB; bisphenol C, BPC; bisphenol E, BPE; bisphenol F, BPF; bisphenol S, BPS) were analyzed using GC-MS. The range ofMDLs by SPE and LLEmethodswas 0.0005∼0.0234 μg/L and 0.0037∼0.2034 μg/L, and that of LOQswas 0.0015∼0.0744 μg/L and 0.0117∼0.6477 μg/L, respectively. The calibration curve obtained from standard solution of 0.004∼4.0 μg/L(SPE) and 0.016∼16 μg/L (LLE) showed good linearity with r2 value of 0.9969 over. Accuracy was 93.2∼108% and 97.4∼120%, and precisionwas 1.7∼4.6%and 0.7∼6.5%, respectively. The values of MDL and LOQ resulted from the SPE method were higher than those from the LLE method, particularly those values of BPAwere highest among theBPs. Based on the results, the SPE method was applied to determine the BPs in river water samples. Water samples were collected from mainstream, tributary and sewage wastewater treatment plants (SWTPs) in theYeongsan river basin. The concentration of BPB, BPC, BPE, BPF andBPSwere not detected in all sites, whereas BPA was ranged 0.0095∼0.2583 μg/L, which was 0.0166∼0.0810 μg/L for mainstreams, 0.0095∼0.2583 μg/L for tributaries, 0.0352∼0.1217 μg/L for SWTPs.

    CONCLUSION:

    From these results, the SPE method was very effective for the simultaneous determination of BPs in river water samples using GC-MS.We provided that it is a convenient, reliable and sensitive method enough to monitor and understand the fate of the BPs in aquatic ecosystems.

  • Effect of Nitrogen Fertigation on The Growth and Nutrition Uptake of ‘Brightwell’ Rabbiteye Blueberry
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    BACKGROUND:

    Rabbiteye blueberry(Vaccinium ashei Reade) has lownutrient uptake efficiency due to its shallow and fibrous root system without root hairs. This study was carried out to establish an efficient nutrient application standard by investigating the effect of nitrogen fertigation on the growth and fruit characteristics of rabbiteye blueberry.

    METHODS AND RESULTS:

    ‘Brightwell’ rabbiteye blueberry was treated with 0, 50, 100 and 200% nitrogen fertigation of recommended fertilizer application (6, 9 and 14 g/bush in the first, second and third years, respectively). The results showed that leaf nitrogen content significantly correlated with the fruit weight and fruit yield. However, canopy area, dry weight, sugar and anthocyanin contents did not correlate significantlywith the leaf nitrogen content. The leaf and stem dry weights of ‘Brightwell’ rabbiteye blueberry during the third year of plantingwere the highest with 50% nitrogen fertigation (leaf dry weight=723.7 g/bush; stem dry weight=890.7 g/bush). Maximum fruit yield of ‘Brightwell’ rabbiteye blueberry (12.9 kg/bush) was observed during the third year of planting with 50% nitrogen fertigation and thiswas about 70%greater than the treatment that received no nitrogen fertigation. The fruit yields of ‘Brightwell’ rabbiteye blueberry during the third year of planting treated with 100 and 200% nitrogen fertigation were 11.0 and 11.5 kg/bush, and these were 17 and 12%lower than the 50%nitrogen fertigation treatment, respectively. Further, the efficiency of nitrogen utilization was the highest (90%) with 50% nitrogen fertigation and lowest (18%) with 200% nitrogen fertigation.

    CONCLUSION:

    The results of this study suggests that fertigationwith 50%of the recommended fertilizer could be most effective for enhancing the growth and nitrogen use efficiency of rabbiteye blueberry.

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