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Contribution of nitrogen-fixing organisms to the N budget in Trachypogon savannas [An article from: European Journal of Soil Biology]
Book Details
PublisherElsevier
ISBN / ASINB000RR7V30
ISBN-13978B000RR7V32
AvailabilityAvailable for download now
Sales Rank99,999,999
MarketplaceUnited States 🇺🇸
Description
This digital document is a journal article from European Journal of Soil Biology, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
Trachypogon savannas in Venezuela are mainly used for extensive cattle raising. These savannas are currently affected with man-made or natural fires. During fires, 24% of the nitrogen (N) necessary for primary production is lost through volatilisation. More is lost by leaching and/or erosion. Since those losses are not compensated for by N input through precipitation, N balance in these savannas depends on biological mechanisms. In this study we explore the possible forms of biological N fixation, in particular the cyanobacterial activity from soil microbial crusts, and the contribution of grass rhizosphere microorganisms. Determinations were made by using, in situ, the method of acetylene reduction as an estimate of nitrogenase activity (NA). N"2 fixation due to NA in the soil-plant system is 13.7 and 7.8 kg ha^-^1 year^-^1 for the burned and protected plots, respectively. Even considering the lowest fixation values by microbial crusts, they could provide 6% of the N needed for annual production of the vegetation of the savanna under fire, and 9% in the protected savanna. These amounts of N"2 sustained the productivity of the vegetation experiencing periodical fires.
Description:
Trachypogon savannas in Venezuela are mainly used for extensive cattle raising. These savannas are currently affected with man-made or natural fires. During fires, 24% of the nitrogen (N) necessary for primary production is lost through volatilisation. More is lost by leaching and/or erosion. Since those losses are not compensated for by N input through precipitation, N balance in these savannas depends on biological mechanisms. In this study we explore the possible forms of biological N fixation, in particular the cyanobacterial activity from soil microbial crusts, and the contribution of grass rhizosphere microorganisms. Determinations were made by using, in situ, the method of acetylene reduction as an estimate of nitrogenase activity (NA). N"2 fixation due to NA in the soil-plant system is 13.7 and 7.8 kg ha^-^1 year^-^1 for the burned and protected plots, respectively. Even considering the lowest fixation values by microbial crusts, they could provide 6% of the N needed for annual production of the vegetation of the savanna under fire, and 9% in the protected savanna. These amounts of N"2 sustained the productivity of the vegetation experiencing periodical fires.
