The effect of tillage on oxidation of soil organic carbon in organically-managed soil

CSANR Project 098

Status: Complete

Project Summary

Organic agriculture uses tillage for several purposes including incorporation of organic inputs. Tillage also speeds oxidation of inputs and soil organic carbon (SOC). In order to understand and model the potential of organic inputs to change total SOC, we need to better characterize the effect of tillage on the simultaneous mineralization and oxidation of inputs and SOC. We will use the natural abundance of 13C (δ13C) in corn-based manure to facilitate differentiation of input and SOC oxidation in response to tillage in organically managed soil.

We will impose tillage/no-tillage treatments and measure δ13C over the growing season in non-vegetated plots that were amended with manure in 2011. Also in 2012, a repeat of the experiment will be established. By enhancing models of input and soil C turnover and sequestration, we address BIOAg Priority Areas of fertility, soil quality, and organic wastes.

Annual Entries

2012

Principal Investigators: Stewart Higgins
Claudio Stockle
Additional Investigators: Andy Bary
Lynne Carpenter-Boggs
Craig Cogger
Progress Report: http://www.tfrec.wsu.edu/pdfs/P2786.pdf
Grant Amount: $39,752

2013

Principal Investigators: Stewart Higgins
Claudio Stockle
Additional Investigators: Andy Bary
Lynne Carpenter-Boggs
Craig Cogger
Doug Collins
Progress Report: http://csanr.wsu.edu/wp-content/uploads/2012/06/id98-StockleHiggins.pdf

2013

Principal Investigators: Stewart Higgins
Claudio Stockle
Additional Investigators: Andy Bary
Lynne Carpenter-Boggs
Craig Cogger
Doug Collins
Progress Report: http://csanr.wsu.edu/wp-content/uploads/2012/06/98Stockle.pdf

Publications

Carpenter-Boggs, Carlson, Higgins, Stockle. Decomposition of dairy manure assessed in the field by monitoring natural abundance of 13C. SSSAJ.  Accepted for publication.

Impacts and Outcomes

 Short‐Term: We have knowledge of the decomposition dynamics of fresh dairy manure in soil. This information can be immediately used in ongoing modeling efforts to asses environmental
services of organic farming.
 Intermediate‐Term:  When  published,  the  results  will  be  available  to  the  general scientific
community for use in assessing decomposition of cow manure.
 Long‐Term: Future projects by other researchers will be more aware of the advantage of using
naturally occurring stable isotopes to assess decomposition of particular carbon pools within soil
containing complex mixtures of carbon from various sources.