New tools for particle shape analysis of substrate components: initial results and future prospects
Substrate components are classified and selected for mixes in part based on their particle size determined through sieving processes. However, sieving tools and methods do not directly consider particle shape. The irregular shapes and sizes of substrates components create a large pore volume (over 85%), of which the shape and size of particles greatly influence the resulting matric structure of the materials, and therefore their physical properties (water retention, drainage). Particle shape of coco fiber, pine bark, wood fiber and white peat were studied with two dynamic image analyzers: the QicPic and the CPA2, based on wet and dry dispersion, respectively. Distribution of shape descriptors (elongation, circularity and roundness of materials) were calculated and analyzed, in relation to the particle size. Results showed that the materials tested are highly elongated and very angular, with a low circularity. Circularity decreased and elongation increased with an increase in particle size, while roundness remained very low. Despite the different methods of sample preparation and calculation models, both QicPic and CPA2 tools were able to image and quantify similar particle shapes in these substrates effectively.
Durand, S., Jackson, B.E., Bartley, P.C., Fonteno, W.C. and Michel, J.C. (2021). New tools for particle shape analysis of substrate components: initial results and future prospects. Acta Hortic. 1317, 335-342
QicPic, computerized particle analyzer, dynamic image analysis