Extrusion of Different Plants into Fibre for Peat Replacement in Growing Media: Adjustment of Parameters to Achieve Satisfactory Physical Fibre-Properties

Christian Dittrich, Ralf Pecenka, Anne-Kristin Løes, Rafaela Cáceres, Judith Conroy, Francis Rayns, Ulrich Schmutz, Alev Kir, Harald Kruggel-Emden

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)
115 Downloads (Pure)


Peat is a highly contentious input in agriculture. Replacing or reducing peat by substitution with lignocellulosic biomass processed into fibre by twin-screw-extrusion could contribute to more sustainable agriculture with regard to horticultural production. Therefore, plant wastes including pruning from Olea europaea L. and Vitis spp. L., residues from perennial herbs like Salvia spp. L., Populus spp. L. and forest biomass were processed to fibre for peat replacement with a biomass extruder. The water-holding-capacity (WHC), particle-size-distribution and other physical fibre characteristics were determined and compared to peat. The specific energy demand during extrusion was measured for aperture settings from 6–40 mm. No fibre reached the 82% WHC of peat. At the setting of 20 mm of all materials investigated, Salvia performed best with a WHC of 53% and moderate specific energy demand (167 kWh tDM−1) followed by Olea europaea with a WHC of 43% and a low energy demand (93 kWh tDM−1). For Populus, opening the aperture from 20–40 mm decreased energy demand by 41% and WHC by 27%. The drying of biomass for storage and remoistening during extrusion increased the specific energy demand. Despite a lower WHC than peat, all investigated materials are suitable to replace peat in growing media regarding their physical properties.
Original languageEnglish
Article number1185
Pages (from-to)1185
Number of pages21
Issue number6
Publication statusPublished - 10 Jun 2021

Bibliographical note

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Horizon 2020 Organic-PLUS (774340)


  • twin-screw extrusion
  • fibre
  • agricultural residues
  • peat substitution
  • specific energy demand
  • water holding capacity
  • Peat substitution
  • Fibre
  • Agricultural residues
  • Twin-screw extrusion
  • Water holding capacity
  • Specific energy demand

ASJC Scopus subject areas

  • Agronomy and Crop Science


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