Evaluating soil productivity and climate change benefits of woody biochar soil amendments for the US Interior West

Managing our lands to provide for today and the future requires sustainable land management practices that enhance productivity while reducing climate impacts. Proponents claim biochar soil amendments offer a comprehensive solution to enhance soil capacity to deliver water and nutrients to plants while decreasing climate impacts through reduced nitrous oxide (N2O) emissions from fertilizer use and carbon (C) sequestration. This dissertation evaluates such claims for woody biochar applications within the US Interior West; to enhance crop production and reduce N2O emissions in deficit irrigation agricultural systems, and to support forest road restoration efforts. It also employs laboratory incubations and soil biogeochemical modeling to predict and to better understand the controls on biochar's greenhouse gas mitigation potential. The field studies demonstrate that this woody biochar improved soil moisture content but its enhanced capacity to retain water did not alleviate plant water stress when water inputs were low. Similarly, in forest soils, this woody biochar amendment improved plant available N but at levels that did not impact productivity. In lab incubations this woody biochar reduced N2O emissions. While this reduction could not be explained by bulk soil mineral N transformations, the soil moisture regime did affect biochar's ability to reduce N2O emissions. Despite the observed biochar N2O emission reductions in incubated soils, under field conditions biochar effects on N2O emissions were inconclusive. When evaluating biochar's C sequestration potential, soil biogeochemical modeling revealed that 59 percent of the biochar C applied will be sequestered in soils after 100 years. Losses from biochar fragmentation and leaching may constitute a considerable proportion of the C losses. Of the applications considered, C sequestration remains the most promising use for biochar soil amendments within the US Interior West.

Name thesis:degree_name

Doctor of Philosophy (Ph.D.)

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Ecology

Grantor dc:publisher

Colorado State University. Libraries

Year dc:date.issued

2018

Authors dc:creator

• Ramlow, Matthew Alan, author
• Cotrufo, M. Francesca, advisor
• Ogle, Stephen, committee member
• Rhoades, Charles C., committee member
• von Fischer, Joseph, committee member

• C sequestration
• greenhouse gas mitigation
• road decommissioning
• deficit irrigation
• biochar
• nitrous oxide

Statement dc:rights

• Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.

Language dc:language.iso

eng, English

Identifier URI

https://doi.org/10.25675/3.018800

OAI identifier oai:identifier

oai:mountainscholar.org:10217/191388