Shelterbelts, hedgerows and grazed woodlands are an important part of the agricultural landscape in central Alberta. These agroforestry systems provide wildlife habitat, serve as windbreaks, retain snow and water and reduce soil erosion. The trees also capture and store carbon from the atmosphere, which helps to offset greenhouse gas emissions and mitigates impacts of tillage on soil health and productivity.
In 2012, a study was initiated to examine the carbon storage potential of these three agroforestry systems across central Alberta. This study includes 36 sites, with 12 sites of each agroforestry type.
At each site, plots were established in areas with tree cover and adjacent areas without tree cover (crop or pasture). In this study, we are measuring the amount of carbon in vegetation and soils and the carbon escaping to the atmosphere. This study addresses two major questions about the impacts of agroforestry systems: 1) How does carbon storage differ in areas with tree cover compared to areas with crop or pasture cover? 2) Of the three agroforestry types, which system stores the most carbon above- and belowground?
Initial findings suggest that there could be substantial carbon storage benefits for land managers who incorporate tree cover into their agricultural systems. For example, surface soils under tree cover have higher carbon concentrations than those under crop cover. In particular, hedgerow systems have the highest surface soil carbon concentrations, suggesting that soils in these systems could be more effective at storing carbon. Results also suggest that there is more stable carbon in soils under forest cover, meaning carbon in those soils is less likely to be released back into the atmosphere.
Additional data collected in 2014 and 2015 will help shed light on patterns in carbon storage among agroforestry land uses, including soil carbon abundance and stability. Combined, this information will help identify new policies intended to reward farmers for management practices that promote carbon storage and reduce greenhouse gas emissions from agricultural lands.
This project is funded by the Agricultural Greenhouse Gases Program through Agriculture and Agri-Food Canada.