Structural changes of plant residues during decomposition in a compost environment

Summary in the original language of the document

We investigated the actual degradation of plant material during composting by qualitative methods using Scanning Electron Microscopy (SEM) combined with quantitative chemical methods. Decomposition of Mischanthus (Mischanthus oogiformis L.), hemp (Cannabis sativa L.) and wheat (Triticum aestivum L.) straw was observed by placing litterbags containing these materials in compost piles. Hemp and Mischanthus straw were more stable than the wheat straw, but the two materials differed in the way they were degraded despite similar chemical composition. Hemp straw was broken down in more flexible structures compared to the rigid breakdown of Mischanthus straw. We concluded that the anatomical arrangement of the tissue is just as an important part of the decomposition rate as the content of recalcitrant compounds. Thus, when using composted plant materials as growing medium the choice of material must depend not only on nutritional quality but also on structural quality. This study indicates that hemp material might be a good structural component in a compost to be used as a growing medium.