Harvest Timing and Switchgrass Quality in Tennessee.

A domestic supply of energy is important for the nation’s economic security.  The use of multiple sources of energy is important for our long-term economic stability.  Bioenergy is one of sources and switchgrass is one of the feedstocks that can be used to provide a sustainable source of energy that can also enhance rural development.  Improving yields has been a large focus of switchgrass research but switchgrass quality is also an important area.  As future conversion facilities will be interested in feedstock quality as well as quantity, this area requires additional research.  Research on the effects that harvest timing may have on switchgrass nitrogen, phosphorus, potassium, and sulfur is important for a sustainable, high-quality feedstock.  Switchgrass plants from field plots were harvested 8-13 times per year between May and November under a one-cut system to intensively identify changes that take place during the growing season.    Preliminary results indicate that, depending on the nutrient, harvests may be taken 2 to 17 weeks earlier than currently projected in Tennessee (after November 1 or first killing frost).  This could allow for greater flexibility for farmers when managing switchgrass for bioenergy.