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<jats:title>Abstract</jats:title><jats:sec> <jats:title>Purpose</jats:title> <jats:p>Selection for root traits has become a target in (pre-)breeding programs aiming at improving crop ability to capture soil resources. However, the benefit of selected traits in heterogeneous target environments will depend on spatial and temporal interactions between root systems, the soil environment (fertility and water supply) and management (fertiliser placement).</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>We assessed growth and phosphorus acquisition of durum wheat (<jats:italic>Triticum durum</jats:italic> L.) lines defined by contrasting seminal root angles (41° ‘Narrow’ vs 82° ‘Wide’), in response to different soil phosphorus placements and seasonal water dynamics. Responses were evaluated in clear pots (seedlings), rhizoboxes (late-tillering stage) and a custom lysimeter system (flowering stage).</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>The Narrow genotype increased deep soil exploration (down to 50 cm) during early growth, with a tendency to more rapidly acquire phosphorus placed as a deep fertiliser band (25 cm depth). However, genotypic differences in shoot biomass or phosphorus uptake were not apparent at anthesis, in part due to phosphorus-induced changes in phenological development. Contrastingly, the wide genotype increased root growth in the topsoil (0–10 cm) when phosphorus was stratified in this layer and produced greater biomass at anthesis under these conditions. Shoot and root biomass and phosphorus uptake decreased when the topsoil dried out, with the greatest effect observed for phosphorus stratified in this layer.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>The benefits of the selected root angle trait strongly depend on nutrient and water distributions and dynamics in the target environment. Ideotype breeding efforts and farmer selection of genotypes should consider the context in which genotypes will be deployed.</jats:p> </jats:sec><jats:sec> <jats:title>Highlight</jats:title> <jats:p>The interaction between root system architecture and heterogeneous distributions of phosphorus and available water determine the relative performance of durum wheat genotypes with contrasting root angles.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background and aims</jats:title> <jats:p>Low productivity open lichen (<jats:italic>Cladonia</jats:italic> spp.) woodlands have been rapidly expanding in the closed-crown feather moss (<jats:italic>Pleurozium schreberi</jats:italic> (Brid.) Mitt.) boreal forest of eastern Canada. While open-woodland areas are progressing, there is little information on the recoverability of open lichen woodlands back to closed-canopy forests.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>An experimental set-up using moss transplantation was installed on a poor jack pine (<jats:italic>Pinus banksiana</jats:italic> Lamb<jats:italic>.</jats:italic>) stand with a lichen ground cover in 2011. Treatments included: 1) lichen cover removed, 2) lichen cover removed and transplantation of a feather moss cover, 3) lichen control, and 4) a natural jack pine site with feather moss cover (moss control). We extracted tree stem increment cores and collected needles and soil samples for nutrient analysis.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>The transplanted-moss treatment can counteract the adverse effects of lichen on jack pine growth. This treatment enhanced foliar nutrition and soil nutrients, especially ammonium (N-NH<jats:sub>4</jats:sub><jats:sup>+</jats:sup>) and nitrate (N-NO<jats:sub>3</jats:sub><jats:sup>−</jats:sup>). With this treatment, the soil conditions (e.g., soil nutrients, soil moisture) and foliar nutrition were closer to that of moss control. Surprisingly, lichen removal treatment did not improve growth and resulted in poorer jack pine growth and harsher soil conditions.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>Feather moss can establish, survive, and remain healthy in an environment previously occupied by lichen. The replacement of lichen by feather moss establishes soil conditions that appear conducive to better tree growth and have the potential of restoring the productivity of boreal forests in open-canopy lichen woodlands.</jats:p> </jats:sec>