A study recently completed in New Zealand found that adding biochar to the soils of pastures where Cows (ruminants) were grazing sharply decreased the excess nitrous oxide from the cows urine. It appears that the biochar helps the soil absorb the extra gasses although long term testing of the effect of cow urine and pasture with biochar still needs to be done.

You can get the Full Report, or read the Abstract from the American Society of Agronomy web site:
https://www.agronomy.org/publications/jeq/abstracts/40/2/468

Biochar Incorporation into Pasture Soil Suppresses in situ Nitrous Oxide Emissions from Ruminant Urine Patches
by Arezoo Taghizadeh-Toosi,Tim J. Clougha, Leo M. Condronab, Robert R. Sherlocka, Craig R. Andersonb and Robin A. Craigiec
Published in the Journal of Environmental Quality Vol. 40 No. 2, p. 468-476

A summary is here: Can Biochar Help Suppress Greenhouse Gases?

Comment to bioenergy with carbon storage (BECS)
Christoph Steiner, to the Terra Preta Discussion List, November 8, 2007


Carbon-negative bioenergy to cut global warming could drive deforestation:
An interview on BECS with Biopact’s Laurens Rademakers Mongabay.com (November 6, 2007) http://news.mongabay.com/2007/1106-carbon-negative_becs.html


The article on mongabay.com deals about a proposed mechanism for generating carbon-negative bioenergy. Bioenergy with carbon storage (BECS) holds out the prospect of reducing CO2 from the atmosphere while producing carbon-negative energy. The article provides an informative introduction on how “carbon-negativity” is feasible and assumes geosequestration (developed from the “clean coal” industry,
CO2 capture in depleted oil and gas fields, saline aquifers etc.) as the sequestering tool. Laurens Rademakers delineates the risks such as deforestation of tropical rainforests and leakage of geosequestration. In addition these technologies require vast capital inputs and large scale projects.

www.biochar.org - balance carbon and restore soil fertility
Christoph Steiner, Germany