Effects of Short Rotation Willow on Riparian Soil Organic Matter Qualities.

Short rotation willow (SRW) is a promising land management practice in the Prairie Pothole Region (PPR) for supplying bioenergy feedstock. The effects of SRW on soil organic matter (SOM) quantity and characteristics in the riparian zones of PPR wetlands are relevant because of links to GHGs emission and biogeochemical cycling, which are an important concern for agriculture and the environment. In the recent past SRW have been promoted as a tool for mitigating atmospheric CO₂ emissions while providing a renewable energy source. High biomass producing capacity of SRW can substantially enhance the amount of organic matter in the soil, both above- and below-ground, especially by mulching leaf litter and absence of cultivation slows decomposition and further helps to retain organic matter in soil during first rotation. The content and characteristics of SOM within at 0-30cm depth were measured under SRW land management practice in the riparian zones of PPR wetlands and compared to adjacent annual cropland and unmanaged pasture in a field experiment in Indian Head, Saskatchewan, Canada. Total and Water Extractable Soil Organic Carbon were used to assess SOM content and Density Fractionation and Fourier Transform Infrared (FTIR) Spectroscopy were used to characterize the chemical structure of SOM from each land management practice. Detailed characterization will provide an insight into the fate of SOM ability to contribute in biogeochemical cycling in soil; and determine whether soil will continue to accumulate SOM or become an important source of SOM breakdown under SRW during the first rotation.