Laurent Augusto

Comparison of ingrowth cores and ingrowth meshes in root studies: 3 years of data on Pinus pinaster and its understory

Key messagePine fine root biomass, live fraction and specific root length studied after collection with ingrowth cores do not correspond with those collected with ingrowth meshes.AbstractRoot studies are a challenging task, yet they are primordial to improve our understanding of biogeochemical cycles in many ecosystems. Methods reducing operator time and minimizing disturbance while permitting adequate assessment of root dimensions in space and time would naturally be of great relevance. Recently, ingrowth meshes have been proposed as a valuable alternative to existing methods, deployable in remote areas and potentially yielding smaller disturbances along with a reduction in time spent per sample. In this study, we used flexible mesh material in Pinus pinaster production forests. The mesh material (pore size 6 by 6xa0mm) was either applied as cores (15xa0cm deep, 8xa0cm diameter) or as linear meshes (15xa0cm deep, 50xa0cm long), and left in soils for 9, 24, or 36xa0months. Roots were retrieved from both devices and separated over plant species (pine and understory species), diameter class and vitality (live or dead). We expected 1) improved assessment of larger diameter roots in the linear meshes due to a larger mesh surface and 2) less disturbance of the soil for the linear meshes. Results indicate that most patterns were similar between both devices and species, but the meshes resulted in lower ingrowth for all diameter classes, and the cores better reflected the standing biomass. The larger surface of the linear meshes resulted in larger disturbance and did not permit to reduce time per sample. Future research may target ingrowth meshes of reduced size and perhaps of more rigid material.