• Title/Summary/Keyword: agricultural ecosystem

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Seasonal Variation of CO2 Exchange During the Barley Growing Season at a Rice-barley Double Cropping Paddy Field in Gimje, Korea (김제 벼-보리 이모작 논에서 보리재배 기간의 CO2 교환량의 계절적 변화)

  • Min, Sung-Hyun;Shim, Kyo-Moon;Kim, Yong-Seok;Hwang, Hae;Jung, Myung-Pyo;Choi, In-Tae
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.16 no.2
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    • pp.137-145
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    • 2014
  • Rice-barley double cropping system is typical in southwestern part of South Korea. However, the information of carbon dioxide ($CO_2$) exchange for barley growing season has still limited in comparison with rice. Using the eddy covariance (EC) technique, seasonal variation of $CO_2$ exchange was analyzed for the barley growing season at a rice-barley double cropping field in Gimje, Korea. The effects of environmental factors and biomass on the $CO_2$ flux also were investigated. Quality control and gap-filling of flux data were conducted before this analysis and investigation. The results indicated that $CO_2$ uptake increased rapidly at tillering stage and maximum net ecosystem exchange of $CO_2$ (NEE) occurred at the early of May, 2012 ($-11.2gCm^{-2}d^{-1}$), when the heading of barley occurred. NEE, gross primary production (GPP), and ecosystem respiration (Re) during the barley growing season were -348.0, 663.3, and $315.2gCm^{-2}$, respectively. In this study, an attempt has been made to measure NEE, GPP, and Re with the help of the EC system for the barley growing season for the first time in Korea, focusing on $CO_2$ exchange between the biosphere and the atmosphere.

Seasonal Variation of Carbon Dioxide and Energy Fluxes During the Rice Cropping Season at Rice-barley Double Cropping Paddy Field of Gimje (김제 벼-보리 이모작 논에서 벼 재배기간동안의 CO2 및 에너지 플럭스의 계절적 변화)

  • Min, Sung-Hyun;Shim, Kyo-Moon;Kim, Yong-Seok;Jung, Myung-Pyo;Kim, Seok-Cheal;So, Kyu-Ho
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.15 no.4
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    • pp.273-281
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    • 2013
  • Based on the results of continuous flux measurements at the Gimje paddy flux site in the southwestern coast of Korea, carbon dioxide and energy exchanges between customarily cultivated rice-barley double cropping paddy field and the atmosphere during the 2012 rice growing season (from $9^{th}$ Jun. 2012 through $20^{th}$ Oct. 2012) were analyzed. Carbon dioxide and energy (H, LE) fluxes were estimated by the eddy covariance method. Environmental parameters (net radiation, precipitation, etc.) and plant biomass (LAI, plant height, etc.) were measured along with fluxes. After the quality control and gap-filling, the observed fluxes were analyzed. The results have been showed that net ecosystem exchange (NEE), gross primary production (GPP), and ecosystem respiration (Re) during the rice cropping period were -277.1, 710.3, and 433.2 g C $m^{-2}$, respectively.

Economic Value Evaluation of Ecosystem Services in Organic Rice-Fish Mixed Farming System in Paddy Wetland (벼-담수어 유기농 복합생태 논습지의 생태계서비스 경제적 가치평가)

  • Nam, Hongshik;Byeon, Youngwoong;Park, Keechoon;Park, Kwanglai;Lee, Youngmi;Han, Eunjung;Kim, Changhyun;Kong, Minjae;Son, Jinkwan
    • Journal of Wetlands Research
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    • v.22 no.4
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    • pp.286-294
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    • 2020
  • This study aims to economically evaluate rice production and various ecological services provided by organic rice paddy carrying out rice-fish mixed farming. It was also conducted to find a stable structure for increasing the income of rice-producing farmers and promoting ecological services by evaluating the economic feasibility of organic rice paddy for rice-fish mixed farming. As a result of the analysis of expected effects by ecological service functions according to the types of agriculture in the rice-fish mixed farming, general conventional paddy fields were evaluated to have an effect of continuously decreasing biodiversity such as amphibian reptiles, aquatic insects, bird habitats, experience and ecological education, and vegetation diversity, while the biodiversity of organic and rice-fish mixed paddy fields was assessed to increase. As a result of evaluating the economic value, as the area for fish production increases compared to the common practice and organic paddy fields, rice production decreases, but fish production increases and total income was analyzed to increase. In addition, if the value of ecosystem service functions is assessed in the future, it will increase further. It is hoped that these findings will be used as basic data for solving oversupply problems in the rice industry, preserving safe farm income, and improving sustainable farming and ecosystem service functions.

Effects of cultivation ages and modes on microbial diversity in the rhizosphere soil of Panax ginseng

  • Xiao, Chunping;Yang, Limin;Zhang, Lianxue;Liu, Cuijing;Han, Mei
    • Journal of Ginseng Research
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    • v.40 no.1
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    • pp.28-37
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    • 2016
  • Background: Panax ginseng cannot be cultivated on the same land consecutively for an extended period, and the underlying mechanism regarding microorganisms is still being explored. Methods: Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) and BIO-LOG methods were used to evaluate the microbial genetic and functional diversity associated with the P. ginseng rhizosphere soil in various cultivation ages and modes. Results: The analysis of microbial diversity using PCR-DGGE showed that microbial communities were significantly variable in composition, of which six bacterial phyla and seven fungal classes were detected in P. ginseng soil. Among them, Proteobacteria and Hypocreales dominated. Fusarium oxysporum, a soilborne pathogen, was found in all P. ginseng soil samples except R0. The results from functional diversity suggested that the microbial metabolic diversity of fallow soil abandoned in 2003was the maximum and transplanted soil was higher than direct-seeding soil and the forest soil uncultivated P. ginseng, whereas the increase in cultivation ages in the same mode led to decreases in microbial diversity in P. ginseng soil. Carbohydrates, amino acids, and polymers were the main carbon sources utilized. Furthermore, the microbial diversity index and multivariate comparisons indicated that the augmentation of P. ginseng cultivation ages resulted in decreased bacterial diversity and increased fungal diversity, whereas microbial diversity was improved strikingly in transplanted soil and fallow soil abandoned for at least one decade. Conclusion: The key factors for discontinuous P. ginseng cultivation were the lack of balance in rhizosphere microbial communities and the outbreak of soilborne diseases caused by the accumulation of its root exudates.

International Movement of Biocides Regulation (Biocides의 국제적 규제동향)

  • 박정규
    • Environmental Analysis Health and Toxicology
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    • v.15 no.4
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    • pp.115-122
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    • 2000
  • Biocides, or non-agricultural pesticides, are a broad class of chemical. They are including biological agents used to disinfect/sanitize, pesticides for non-agricultural use, wood preservatives, antifoulants, etc. Since the early 1980s, many adverse effects of biocides to human health and ecosystem have been found in the world. Especially, antifouling biocide like TBT caused serious toxic effects on the marine organisms. Therefore, OECD began to work on biocides in mid 1996 to help Member countries co-operate in the assessment and registration of these products. EU also announced the Biocidal Products Directive (BPD, 98/8/EC) in 1998 to harmonize regulatory approaches to allow EU countries to conduct evaluations of biocides more efficiently. Korea just start to consider of biocides regulation. Some biocides products are regulated, but not all the biocides which are using in Korea. Therefore, we need to make a appropriate regulation for the all biocides categories. In addition, there are necessary to develop risk assessment tools, to survey the use pattern and amount, to research on the ecosystem contamination by the biocides .

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