The yield and composition of switchgrass and coastal panic grass grown as a biofuel in Southern England

Switchgrass (Panicum virgatum L.) and coastal panic grass (Panicum amarum A.S. Hitchc. & Chase) are perennial grasses indigenous to North America. Switchgrass has been shown to have good potential as a biofuel crop in both the US and Canada. In the study reported here, seven varieties of switchgrass and one panic grass were evaluated for 5 years under the temperate maritime conditions in Southern England. Both species had 0 or 60 kgNha−1 applied annually in spring as treatment. Yield was measured after flowering and when stems were dead in the winter. Yield increased annually for 4–5 years except for the variety Dacotah, and in the fifth year dead stem yields ranged from 8.82 to13.97 tdmha−1. There was no response to N except for one variety in one year. Mineral concentration in biomass was higher at flowering than at dead stem harvest and delaying harvesting further provided more time for P, K and Cl to be leached but yield also declined.