THE POTENTIAL OF 2 PERENNIAL C-4 GRASSES AND A PERENNIAL C-4 SEDGE ASLIGNOCELLULOSIC FUEL CROPS IN NW EUROPE - CROP ESTABLISHMENT AND YIELDS IN E ENGLAND

Three perennial C-4 rhizomatous species, Cyperus longus L., Spartina c ynosuroides and Spartina pectinata Link. were examined as potential re newable energy crops. These species are unusual among C, plants in sho wing natural distributions which extend into cool temperate regions. T his study examined whether these species could be established in the c ool temperate climate of eastern England and whether they could consis tently attain the relatively high dry matter yields associated with C, plants of warmer regions. Clonally produced material was planted in 1 986, on two sites with contrasting soil types in Essex, eastern Englan d. Planting was within a randomized-block design incorporating replica ted plots of each species, both with and without fertilizer. Survivors hip and stem demography were monitored at monthly intervals from 1986 to Jun. 1989 for stem recruitment and to Dec. 1991 for stem density. Y ields were determined from 1987 (the year following establishment) to 1993. Survivorship of the planted propagules over the first 12 months was 92 % for S. pectinata, 96 % for S. cynosuroides and 100 % for C. l ongus. Recruitment of new stems peaked in Apr. of most years, although a significant number of new stems appeared as early as Feb. Stem deat h peaked in Sep. or early Oct. and all above-ground stems had died by mid-Nov. Stem density trends indicated that 2-4 years were required to reach a steady-state density, depending upon species. The stem densit y of the two Spartina species had reached more than 1000 m(-2) in 1989 although that of S. pectinata fluctuated considerably in the subseque nt years. C. longus stem density rose to approx. 600 m(-2) by 1988 and did not change significantly in the subsequent years. In the 6 years following establishment, annual yields averaged across all fertilizer treatments and both sites were 1.0, 1.1 and 1.3 kg m(-2) for C. longus , S. cynosuroides and S. pectinata, respectively. The average annual y ield of all three species at the site with the heavier soil was 1.3 kg m(-2). This was significantly greater than the 1.0 kg m(-2) on the li ghter soil. Nitrogen addition did not significantly increase yield. Ev en in the absence of any nitrogen addition, the annual yield of S. pec tinata averaged 1.2 kg m(-2) over the 6 years, with no evidence of any decline with the increasing age of the stands. (C) 1995 Annals of Bot any Company