Switchgrass has been proposed as a biofuel feedstock in the US. Studies in the past decades have shown that switchgrass is able to produce sizable biomass with varied management practices. Recent studies have focused on its cultivation impact on the environment, including water use, nitrate leaching and soil water content. However, little research has evaluated switchgrass aboveground biomass production across lands with varied quality across Michigan nor has research quantified factors limiting switchgrass aboveground biomass. This thesis attempted to fill the research gap. The Systems Approach to Land Use Sustainability model was used to assess switchgrass aboveground net primary productivity (ANPP) and evapotranspiration (ET) across Michigan in 1981-2010 and 2039-2068 and to quantify limited nitrogen and water effect on switchgrass aboveground biomass potential reduction. The results showed that switchgrass ANPP would decrease in 2039-2068 compared to 1981-2010 for a majority region in Michigan. Its ET would increase in 2039-2068 compared to 1981-2010 for most of Michigan but the increase in ET would be attributed to higher soil water evaporation in 2039-2068. The limited nitrogen would affect switchgrass ANPP production less in 2039-2068 than in 1981-2010. However, limited water would affect its production more in the projected future.
Read
