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Can biochar mitigate nitrogen losses...

Pereira, Engil Isadora Pujol.

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Can biochar mitigate nitrogen losses in organic farming systems?

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Can biochar mitigate nitrogen losses in organic farming systems?/
作者:	Pereira, Engil Isadora Pujol.
面頁冊數:	130 p.
附註:	Source: Dissertation Abstracts International, Volume: 76-04(E), Section: B.
Contained By:	Dissertation Abstracts International76-04B(E).
標題:	Agriculture, Soil Science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3646370
ISBN:	9781321363654

Can biochar mitigate nitrogen losses in organic farming systems?
Pereira, Engil Isadora Pujol.

Can biochar mitigate nitrogen losses in organic farming systems? - 130 p.

Source: Dissertation Abstracts International, Volume: 76-04(E), Section: B.

Thesis (Ph.D.)--University of California, Davis, 2014.

This item must not be sold to any third party vendors.

Nitrogen (N) management represents a challenge for organic farming systems. In particular, sufficient N mineralization is not always achieved, timing of N release and plant uptake is often not synchronized, and subsequent N transformations of mineralized N may be lost as environmental pollutants (e.g., leached N and nitrous oxide (N2O) emissions). Biochar, the charcoal obtained from the thermal decomposition of biomass waste under limited oxygen supply, has the potential to alter soil physicochemical properties that regulate the retention of soil N. This dissertation evaluates biochar as a means to improve N management in organic farming systems by reducing environmental N losses and stabilizing N within the agricultural landscape. The following three experiments investigated these conditions using a multi-scale approach, including an on-farm trial and greenhouse experiments, high-frequency assessment of greenhouse gases (GHGs), 15N pool dilution techniques, and microbial analysis.

ISBN: 9781321363654Subjects--Topical Terms:

1017824
Agriculture, Soil Science.

Can biochar mitigate nitrogen losses in organic farming systems?
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245 1 0 $a Can biochar mitigate nitrogen losses in organic farming systems?
300 $a 130 p.
500 $a Source: Dissertation Abstracts International, Volume: 76-04(E), Section: B.
500 $a Adviser: Johan Six.
502 $a Thesis (Ph.D.)--University of California, Davis, 2014.
506 $a This item must not be sold to any third party vendors.
506 $a This item must not be added to any third party search indexes.
520 $a Nitrogen (N) management represents a challenge for organic farming systems. In particular, sufficient N mineralization is not always achieved, timing of N release and plant uptake is often not synchronized, and subsequent N transformations of mineralized N may be lost as environmental pollutants (e.g., leached N and nitrous oxide (N2O) emissions). Biochar, the charcoal obtained from the thermal decomposition of biomass waste under limited oxygen supply, has the potential to alter soil physicochemical properties that regulate the retention of soil N. This dissertation evaluates biochar as a means to improve N management in organic farming systems by reducing environmental N losses and stabilizing N within the agricultural landscape. The following three experiments investigated these conditions using a multi-scale approach, including an on-farm trial and greenhouse experiments, high-frequency assessment of greenhouse gases (GHGs), 15N pool dilution techniques, and microbial analysis.
520 $a The first experiment examined the effects of a variety of biochar amendments on plant performance, soil properties and N transformation rates in a mesocosm representing an organic lettuce production system (Lactuca sativa ). N2O fluxes were monitored throughout the growing period as well as functional genes that encode nitrification (amoA) and denitrification (nirK, nirS, and nosZ) enzymes of bacteria. Findings from this study indicate that some biochars may accelerate N mineralization from organic fertilizer and increase net nitrification. Decreases in N2O fluxes were only observed for a short period, not leading to significant effects in total emissions. The second experiment examined whether biochar amendments reduce N losses from soils and improve plant performance and whether these effects are N level dependent. Fertilizer inputs, N output through harvest, leachate, and N2O emissions were used to assess N utilization and environmental losses of biochar-amended soils. These evaluations were carried out for two growing seasons in a mesocosm representing an organic lettuce production system. Analyses of plant performance indicate that biochar amendments did not provide any increases in plant biomass in soils that received less than commercial fertilization rates (225 kg N ha -1). At commercial fertilization rates, biochar increased N use efficiency (NUE) and decreased N losses via leaching, which lead to a significant decrease in ratio of N lost over N exported in biomass. N2O emissions were altered by biochar amendments only in soils that received 50% of commercial fertilization rates (112 kg N ha-1), which did not alter the ratio of N lost over N exported in biomass.
520 $a The third experiment provides an on-farm high frequency assessment of GHG emissions from biochar amended-soils in an organic walnut orchard, in addition to an estimate of the GHG savings from the conversion of orchard residue into utility grade energy. Despite observed short-term decreases, biochar alone or in combination with compost did not alter total CO2 and N2O emissions from soils; whereas, the conversion of orchard residue into energy and C sequestration through soil amendment lead to a carbon credit of 100.3 Mg CO2-Ceq per year.
520 $a In conclusion, biochar did not decrease total N2O emissions from soils, but occasionally reduced N losses via leachate and improved plant utilization of N. A larger long-term environmental benefit of biochar was found to occur when using orchard residue for energy generation and C sequestration in soils.
590 $a School code: 0029.
650 4 $a Agriculture, Soil Science. $3 1017824
650 4 $a Biogeochemistry. $3 545717
650 4 $a Sustainability. $3 1029978
690 $a 0481
690 $a 0425
690 $a 0640
710 2 $a University of California, Davis. $b Horticulture and Agronomy. $3 1676792
773 0 $t Dissertation Abstracts International $g 76-04B(E).
790 $a 0029
791 $a Ph.D.
792 $a 2014
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3646370