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Soil nitrogen transformations under ...

Pereira, Engil Isadora Pujol.

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Soil nitrogen transformations under elevated carbon dioxide and ozone concentrations during the growing season of soybean.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Soil nitrogen transformations under elevated carbon dioxide and ozone concentrations during the growing season of soybean./
Author:	Pereira, Engil Isadora Pujol.
Description:	50 p.
Notes:	Source: Masters Abstracts International, Volume: 48-06, page: 3462.
Contained By:	Masters Abstracts International48-06.
Subject:	Agriculture, Agronomy. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=1477102
ISBN:	9781124025674

Soil nitrogen transformations under elevated carbon dioxide and ozone concentrations during the growing season of soybean.
Pereira, Engil Isadora Pujol.

Soil nitrogen transformations under elevated carbon dioxide and ozone concentrations during the growing season of soybean. - 50 p.

Source: Masters Abstracts International, Volume: 48-06, page: 3462.

Thesis (M.S.)--University of California, Davis, 2010.

The increasing atmospheric concentrations of CO2 and O 3 are likely to alter ecosystem functioning by modifying rates of plant photosynthesis and production of plant biomass. Soil microorganisms that are driven by the amount and quality of plant organic material conduct crucial ecosystem processes, such as N cycling. This study aims to investigate how soil N cycling will respond to elevated CO2 and O3. More specifically, it focuses on the changes in nitrifiers and denitrifiers communities, as well as N transformation processes, under elevated CO 2 and O3 conditions within the growing season and across soil environments (i.e., rhizosphere and bulk soil). We determined changes in soil available N and in gene abundance of total bacteria (16S rRNA), nitrifiers (amoA) and denitrifiers (nosZ), caused by elevated CO2 and O3 in the rhizosphere and bulk soil of a soybean (Glycine max (L.) Merr.) agroecosystem. Soil samples were collected at different phenological stages of the soybean plants: fourth trifoliolate leaf (V4), full pod (R4), and full maturity (R8) during the 2008 growing season at the SoyFACE experiment in Champaign-Urbana, Illinois. The abundance of 16S rRNA genes ranged from 1.54 x 108 to 3.77 x 108 copies g-1 soil. Elevated CO2 increased 16S rRNA gene abundance during R8 compared to V4 and R4. The amoA gene abundance ranged from 6.5 x 106 to 1.5 x 107 copies g-1 soil, but neither elevated CO 2 nor O3 had significant effects on amoA abundance. The nosZ gene abundance ranged from 2.87 x10 5 to 4.18 x 106 copies g-1 soil and was significantly more abundant in the rhizosphere compared to the bulk soil. Although not statistically significant, elevated O3 tended to increase the abundance of nosZ, whereas elevated CO2 did not change nosZ abundance. In contrast to our expectations, the effects of elevated CO2 and O3 on the measured variables were not more pronounced in the rhizosphere compared to the bulk soil. Although total soil N was significantly higher under elevated than ambient O3 conditions, elevated O3 decreased soil mineral N through a reduction in plant material input and increased denitrification, which was indicated by the higher abundance of nosZ. Elevated CO 2 did not alter any of the parameters evaluated and elevated CO 2 and O3 showed no interactive effects on nitrifier and denitrifier communities nor on the concentration of total and mineral N in soil. Sampling event, which corresponded to the different plant phenological stages did not show any interaction effects with CO2 and O 3 on N dynamics.

ISBN: 9781124025674Subjects--Topical Terms:

1018679
Agriculture, Agronomy.

Soil nitrogen transformations under elevated carbon dioxide and ozone concentrations during the growing season of soybean.
LDR:04022nam 2200337 4500 001 1398203
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020 $a 9781124025674
035 $a (UMI)AAI1477102
035 $a AAI1477102
040 $a UMI $c UMI
100 1 $a Pereira, Engil Isadora Pujol. $3 1677083
245 1 0 $a Soil nitrogen transformations under elevated carbon dioxide and ozone concentrations during the growing season of soybean.
300 $a 50 p.
500 $a Source: Masters Abstracts International, Volume: 48-06, page: 3462.
500 $a Adviser: Johan Six.
502 $a Thesis (M.S.)--University of California, Davis, 2010.
520 $a The increasing atmospheric concentrations of CO2 and O 3 are likely to alter ecosystem functioning by modifying rates of plant photosynthesis and production of plant biomass. Soil microorganisms that are driven by the amount and quality of plant organic material conduct crucial ecosystem processes, such as N cycling. This study aims to investigate how soil N cycling will respond to elevated CO2 and O3. More specifically, it focuses on the changes in nitrifiers and denitrifiers communities, as well as N transformation processes, under elevated CO 2 and O3 conditions within the growing season and across soil environments (i.e., rhizosphere and bulk soil). We determined changes in soil available N and in gene abundance of total bacteria (16S rRNA), nitrifiers (amoA) and denitrifiers (nosZ), caused by elevated CO2 and O3 in the rhizosphere and bulk soil of a soybean (Glycine max (L.) Merr.) agroecosystem. Soil samples were collected at different phenological stages of the soybean plants: fourth trifoliolate leaf (V4), full pod (R4), and full maturity (R8) during the 2008 growing season at the SoyFACE experiment in Champaign-Urbana, Illinois. The abundance of 16S rRNA genes ranged from 1.54 x 108 to 3.77 x 108 copies g-1 soil. Elevated CO2 increased 16S rRNA gene abundance during R8 compared to V4 and R4. The amoA gene abundance ranged from 6.5 x 106 to 1.5 x 107 copies g-1 soil, but neither elevated CO 2 nor O3 had significant effects on amoA abundance. The nosZ gene abundance ranged from 2.87 x10 5 to 4.18 x 106 copies g-1 soil and was significantly more abundant in the rhizosphere compared to the bulk soil. Although not statistically significant, elevated O3 tended to increase the abundance of nosZ, whereas elevated CO2 did not change nosZ abundance. In contrast to our expectations, the effects of elevated CO2 and O3 on the measured variables were not more pronounced in the rhizosphere compared to the bulk soil. Although total soil N was significantly higher under elevated than ambient O3 conditions, elevated O3 decreased soil mineral N through a reduction in plant material input and increased denitrification, which was indicated by the higher abundance of nosZ. Elevated CO 2 did not alter any of the parameters evaluated and elevated CO 2 and O3 showed no interactive effects on nitrifier and denitrifier communities nor on the concentration of total and mineral N in soil. Sampling event, which corresponded to the different plant phenological stages did not show any interaction effects with CO2 and O 3 on N dynamics.
520 $a This study shows that elevated CO2 may have limited effects on terrestrial N transformations in soybean agroecosystems, but elevated O 3 can lead to a decrease in plant N availability in both the rhizosphere and bulk soil. In conclusion, in addition to reducing photosynthetic rates, elevated O3 can also affect ecosystem productivity by reducing the mineralization rates of plant-derived residues.
590 $a School code: 0029.
650 4 $a Agriculture, Agronomy. $3 1018679
650 4 $a Climate Change. $3 894284
650 4 $a Environmental Geology. $3 1672929
650 4 $a Agriculture, Soil Science. $3 1017824
690 $a 0285
690 $a 0404
690 $a 0407
690 $a 0481
710 2 $a University of California, Davis. $b Horticulture and Agronomy. $3 1676792
773 0 $t Masters Abstracts International $g 48-06.
790 1 0 $a Six, Johan, $e advisor
790 1 0 $a van Kessel, Chris $e committee member
790 1 0 $a Scow, Kate M. $e committee member
790 $a 0029
791 $a M.S.
792 $a 2010
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=1477102