Reynoutria bohemica - an alternative Miscanthus x giganteus?

In the relative absence of reports on Reynoutria as a possible alternative to Miscanthus both as perennial "renewable resources", cultivation effects on plant development and yield were tested in field trials at Dikopshof exp erimental station of Bonn University. Miscanthus was planted in 1935 with d ensities of either 1 plant/m(2) or 4 plants/m(2) and Reynoutria in 1996 wit h either 1 plant/m(2) or 3 plants/m(2) and either 0 or 200 kg nitrogen/ha a s mineral fertilizer. The majority of Miscanthus plants was damaged in the first winter after the planting due to the lack of frost hardiness. Plant d evelopment and dry matter were determined in the first two and first three years, respectively. In the final years 1938/99, techniques were examined t o remove the 3 and 4 year-old Reynoutria and the 4 and 5 year-old Miscanthu s. In the first year, Miscanthus formend a larger number of shoots with up to 57 shoots/plant and Reynoutria higher shoots of up to 223 cm. Miscanthus ou tyielded Reynoutria in the first two years, a situation which reversed in t he third year with 24.2 t dry matter per hectare. The higher plant densitie s both in Reynoutria and also in Miscanthus produced a larger number of sho ots/m(2) and higher yields in the three years. The future development will be assessed. Nitrogen fertilization affected plant development and dry matt er only of Reynoutria. In the year 1998 the removing of Miscanthus and Reyn outria with Round up, cultivating or regular mowing caused considerable pro blems. The perennial results indicate that Reynoutria reaches actually the high yield of Miscanthus. While Reynoutria shows advantages in winter hardi ness the removal is very difficult. For this reason Miscanthus should be pr eferred as far as the planned utilization allows that.