Ballesteros to defend dissertation

William Ballesteros Possu, doctoral student, will defend his dissertation at 1 p.m., June 26 in Hardin Hall, Room 901.
William Ballesteros Possu, doctoral student, will defend his dissertation at 1 p.m., June 26 in Hardin Hall, Room 901.

William Ballesteros Possu, doctoral student, will defend his dissertation at 1 p.m., June 26 in Hardin Hall, Room 901.

His dissertation is titled, "Carbon Storage and Potential of Windbreaks on Agricultural Lands of the Continental United States." His adviser is Jim Brandle.

Abstract:

Agricultural production systems face major challenges under climate change scenarios, in terms of expected negative impacts on productivity and persistence of the crops. Greenhouse gases (GHG) from agriculture continue to rise although not as fast as from other fossil fuel-based human activities. Windbreaks perform several ecosystems functions that improve the local and regional capacity of crop systems to increase yields and offer environmental services by minimizing the negative effects of extreme weather events. Field windbreaks also represent an important means of mitigating greenhouse gas emissions. This is predominantly accomplished by the windbreak trees storing carbon (C) in their above and belowground woody tissue while reducing carbon dioxide (CO2) emissions either through avoidance of emissions or through energy savings. However, available and reliable data for estimating crop windbreak contributions to whole-farm and regional C assessments are scarce and in most regions do not exist.

We investigated the C storage potential of windbreaks and the extent of potential reduction in emissions due to the presence of windbreaks in different farming scenarios in the Continental U.S. We compared the performance of many allometric equations to determine the C storage potential of some windbreak tree species in different regions of the continental U.S., 2) analyzed the reduction of carbon equivalent (CE) emissions for different crops by planting windbreaks, and 3) evaluated hypothetical farms synthesized with different windbreak designs together with cropping systems and farmstead. These scenarios were evaluated in the way they best can offset their C emissions.

Jenkin's model was the best tool for estimating biomass/C storage potential for windbreaks. Different windbreak designs can offset C emissions from cropping systems in small and large-scale farms. Windbreaks have an important impact in C emissions reduction when planted in agricultural lands. Two- or three row field windbreaks can offset most C crop emissions. Key aspects of the windbreak potential for offsetting C emissions in farming operations included: site conditions, tree species, house size, windbreak designs, and farmers willingness to adopt these changes. The findings from this project provide further evidence of the role crop windbreaks can play in GHG mitigation in agriculture and describe a reasonable, science-based approach for estimating the level of these contributions.