Sedum root foraging in layered green roof substrates
Background and aims
Layered profiles of designed soils may provide long-term benefits for green roofs, provided the vegetation can exploit resources in the different layers. We aimed to quantify Sedum root foraging for water and nutrients in designed soils of different texture and layering.
In a controlled pot experiment we quantified the root foraging ability of the species Sedum album (L.) and S. rupestre (L.) in response to substrate structure (fine, coarse, layered or mixed), vertical fertiliser placement (top or bottom half of pot) and watering (5, 10 or 20 mm week−1).
Water availability was the main driver of plant growth, followed by substrate structure, while fertiliser placement only had marginal effects on plant growth. Root foraging ability was low to moderate, as also reflected in the low proportion of biomass allocated to roots (5–13%). Increased watering reduced the proportion of root length and root biomass in deeper layers.
Both S. album and S. rupestre had a low ability to exploit water and nutrients by precise root foraging in substrates of different texture and layering. Allocation of biomass to roots was low and showed limited flexibility even under water-deficient conditions.
KeywordsGreen roof Sedum Vegetation Root foraging Substrate texture and layering
This study was funded by the Regional research fund for Western Norway (project 239039), a strategic institutional programme to the Norwegian Institute of Bioeconomy Research (NIBIO) through the Research Council of Norway (project 248349/F40), the National Natural Science Foundation of the People’s Republic of China (No. 31401892) and the Doctoral Foundation of Heilongjiang Bayi Agricultural University (xdb2013-02).
Compliance with Ethical Standards
Conflict of interest
The authors declare that they have no conflicts of interest. Funding parties had no role in planning, conducting or publishing the study.
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