Water Use of Miscanthus and Corn on Marginal Land in the North Carolina Coastal Plain Region

Bioenergy crops are being promoted as an alternative option to reduce dependence on finite fossil fuel reserves. Current research shows that miscanthus can yield substantial amounts of biomass with relatively low inputs of water and fertilizer, making it a potential candidate for land areas considered “marginal”. However, relatively little is known about miscanthus water use for the conditions of North Carolina (NC). Here we present data from a study designed to compare the water use of miscanthus and corn fields grown in marginal land at the Coastal Plain region of NC. Soil at the site is a loamy sand with low water holding capacity. Energy and water fluxes were obtained by means of the Bowen ratio energy balance method. Measurements during the 2021 growing showed that canopy structure and length of the growing season played an important role in explaining differences in water use patterns between the two crops. Due to greater leaf are index (LAI), miscanthus intercepted more radiant energy than corn, which resulted in lower soil heat fluxes. Consequently, available energy was greater for miscanthus throughout the growing season, which resulted in greater latent heat fluxes when compared to corn. At the end of the season a deficit of 129 mm of water was observed for Miscanthus, whereas corn left a surplus of 70 mm. Results suggested that biomass production by bioenergy crops in marginal lands is obtained at the expense of substantial amounts of water.