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Open Access Journal

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 2016. Vol.35, Iss.4more..

  • Effect of Phosphate Application on Cadmium Extractability and its Uptake by Rice Cultivated in Contaminated Paddy Soil
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    BACKGROUND:

    To determine effect of phosphate (P) application on Cadmium (Cd) extractability and its uptake by rice plant in Cd contaminated paddy soil, dipotassium (K2HPO4) which was the most effective of P materials to decrease Cd extractability in previous study was selected as P fertilizer.

    METHODS AND RESULTS:

    Dipotassium phosphate was applied at the rates of 0, 78, 234, and 390 kg P2O5/ha, and then rice was cultivated in submerged paddy soil from Jun. to Oct. in 2015. Cadmium concentrations in grain, straw, and root of rice plant decreased significantly with increasing application rate of K2HPO4. The trend of 1 M NH4OAc extractable Cd concentration in soil was similar to that of Cd uptake by rice plant. One M NH4OAc extractable Cd concentration was negatively related to soil pH and negative charge. Alleviation of Cd phytoavailability of rice in paddy soil might be attributed to increase in pH and negative charge of soil. Using a quadratic response model, amount of grain yield were related to K2HPO4 application rates as Grain yield = 5.38 + 2.39 ×10-3 K2HPO4 – 6.65 × 10-6 K2HPO4 2 (model R2 = 0.968). Using this equations, the greatest grain yield (5.6 Mg/ha) was at the rate of 180 kg P2O5/ha. At this application rate of P, the Cd concentration in grain was 0.53 mg/kg, implying ca. 23% lower than the control.

    CONCLUSION:

    From the view point of heavy metal safety and crop productivity, it might be good P management to apply P fertilizer with 4 times higher rate than recommendation (45 kg/ha).

  • Synergistic and Antagonistic Interactions for Pesticide mixtures to Honeybee Larvae Toxicity
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    BACKGROUND:

    Recently, the widespread distribution of pesticides in the hive has been of concern about pesticide exposure on honeybee (Apis mellifera L.) health. Larval toxicity was adapted to assess the synergistic and antagonistic interaction of cumulative mortality to the honeybee larvae of the four most common pesticides detected in pollen.

    METHODS AND RESULTS:

    Acetamiprid(3.0 ㎕/L), chlorothalonil (803.0 ㎕/L), coumaphos (128.0 ㎕/L), and tau-fluvalinate (123.0 ㎕/L) were tested in combination; binary, ternary and four component mixture. Larvae were exposed to four pesticides mixed in diet at the average levels detected in pollen. As a result, synthetic toxicity was observed in the binary mixture of acetamiprid with coumaphos. The binary and ternary component mixtures of tested pesticides have mostly demonstrated additive effect in larval bees. The significant antagonistic effects were found in four parings of mixtures including chlorothalonil added to acetamiprid/tau-fluvalinate or acetamiprid/coumaphos/tau-fluvalinate, and tau-fluvalinate added to acetamiprid/chlorothalonil or acetamiprid/coumaphos/chlorothalonil.

    CONCLUSION:

    Interactions between combinations of four pesticides showed mostly additive or antagonistic effects in larval bees. Therefore, predicting the larval mortality of pesticides mixtures on the basis of the results of single pesticide may actually overestimate the risk. We suggest that pesticide mixture in pollen be evaluated by adding their toxicity together for complete data on interactions.

  • Factors Influencing the Acrylamide Content of Fried Potato Products
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    BACKGROUND:

    Acrylamide (CAS No. 79-06-1) is known to be a carcinogenic compound, and is classified as a Group 2A compound by the International Agency for Research on Cancer (IARC, 1994). Acrylamide can be generated during the browning process via the non-enzymatic Maillard reaction of carbohydrates such as reducing sugars and of amino acids such as asparagine, both of which occur at a temperature above 120℃. Potato tubers contain reducing sugars, and thus, this will affect the safety of processed potato products such as potato chips and French fries. In order to reduce the level of acrylamide in potato processed products, it is therefore necessary to understand factors that affect the reducing sugar content of potatoes, such as environmental factors and potato storage conditions, as well as understanding factors affecting acrylamide formation during potato processing itself.

    METHODS AND RESULTS:

    Potatoes were cultivated in eight regions of Korea; For each of these different environments, soil physico-chemical characteristics such as pH, electrical conductivity, total nitrogen, available phosphate, and exchangeable cation content were measured and correlations with potato reducing sugar content and potato chip acrylamide levels were examined. The reducing sugar content in potato during storage for three months was determined and acrylamide level in potato chip was analyzed after processing. The storage temperature levels were 4℃, 8℃, or 10℃, respectively. The acrylamide content of chips prepared from potatoes stored at 10℃ or 2 0℃ for one month was analyzed and the different frying times were 2, 3, 5, and 7 min.

    CONCLUSION:

    This study showed that monitoring and controlling the phosphate content within a potato field should be sufficient to avoid producing brown or black potato chips. For potatoes stored at low temperatures, a reconditioning period (20℃ for 20 days) is required in order to reduce the levels of reducing sugars in the potato and subsequently reduce the acrylamide and improve chip coloration and appearance.

  • Effect of Girdling on the Flowering and Yield in Scion Rooted ‘Shiranuhi’ Mandarin grown in Plastic Film House
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    BACKGROUND:

    ‘Shiranuhi’ mandarin is one of the popular citrus cultivars in Jeju Island, Korea. However, the emergence of scion roots since the past few years has altered its flowering, fruiting, and quality. Girdling of branches is one of the methods of increasing flowering in citrus trees.

    METHODS AND RESULTS:

    This experiment was conducted to determine the effect of girdling on the flowering and yields of scion rooted ‘Shiranuhi’ mandarin hybrid. We selected normal trees without scion roots as controls. The trees with scion roots were divided into two groups: trees without girdling and with girdling on main branches. Each group contained five replications and the experiment was conducted in Gosan and Harye of Jeju Island. The scion rooted trees revealed severely decreased flowering and low flowering/leaf ratios; however, the leaf/fruit ratio significantly increased. But, girdling on main branches significantly increased flowering and the flowering/leaf ratio. In the scion rooted trees, yields dropped due to poor flowering; however, girdling of branches efficiently improved the yields of the trees. Fruit quality, fruit size, and fruit weight of scion rooted trees were low in comparison with the control, whereas girdling of the branches improved flowering and the fruit weight to some extent. No significant difference in soluble solid contents was observed.

    CONCLUSION:

    Girdling is an effective method to induce flowering of the scion rooted ‘Shiranuhi’ mandarin trees. In addition, yields of scion rooted trees were improved.

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