Morphological and mechanical properties of Miscanthus in relation to harvesting, lodging, and growth conditions

Field experiments with Miscanthus 'giganteus' and Miscanthus 'sinensis' inc luding studies concerning effects of harvest time, lodging, pruning, and fe rtilisation on morphological and mechanical properties were conducted. Stem length increased from the first to the second harvest and then decreased d ue to natural internode abscission starting at the upper internodes. An ave rage of three internodes was lost from the stems. The lengths of internodes 2 and 4 were independent of harvest time. However, the lengths of the uppe r internodes were at a minimum at harvest times 2-4. The internode length i ncreased from the second to the fourth internode and then followed by a dec rease. Outer diameter, inner diameter, culm wall thickness, moment of inert ia, modulus of elasticity, and flexural rigidity decreased from the lower t o the upper nodes and internodes. Average internode length, culm wall thick ness, internal diameter, outer diameter, moment of inertia (I) of internode s, and modulus of elasticity of internodes were not influenced by harvest t ime. Moment of inertia was high and modulus of elasticity was low for inter nodes compared to the nodes. However, the flexural rigidity was highest for internodes. The measured values for modulus of elasticity ranged from 2-8 GPa. Pruning of the crop and use of a minimum of nitrogen fertilizer reduce d the risk of lodging. (C) 2001 Elsevier Science B.V. All rights reserved.