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The complexity of wood ash fertilization disentangled : Effects on soil pH, nutrient status, plant growth and cadmium accumulation

Johansen, Jesper Liengaard ; Nielsen, Maiken Lundstad ; Vestergård, Mette ; Mortensen, Louise Hindborg ; Cruz-Paredes, Carla LU orcid ; Rønn, Regin ; Kjøller, Rasmus ; Hovmand, Mads ; Christensen, Søren and Ekelund, Flemming (2021) In Environmental and Experimental Botany 185.
Abstract

Wood ash is a by-product from energy production that can be recycled to forests to regain nutrients and prevent acidification. However, low concentrations of nitrogen (N) in wood ash may reduce its potential positive effect on plant growth. In addition, wood ash can have a high content of toxic heavy metals such as Cd, thus there are concerns that it may increase Cd accumulation in plants. We grew Deschampsia flexuosa (Wavy hair-grass) in pots in acidic nutrient poor forest soil fertilized with different concentrations of wood ash (corresponding to field application of 0, 1.1, 3.3, 11 and 33 t ha−1). Additionally, to disentangle the pH and nutrient effects of wood ash application, we included treatments with either CaO, to... (More)

Wood ash is a by-product from energy production that can be recycled to forests to regain nutrients and prevent acidification. However, low concentrations of nitrogen (N) in wood ash may reduce its potential positive effect on plant growth. In addition, wood ash can have a high content of toxic heavy metals such as Cd, thus there are concerns that it may increase Cd accumulation in plants. We grew Deschampsia flexuosa (Wavy hair-grass) in pots in acidic nutrient poor forest soil fertilized with different concentrations of wood ash (corresponding to field application of 0, 1.1, 3.3, 11 and 33 t ha−1). Additionally, to disentangle the pH and nutrient effects of wood ash application, we included treatments with either CaO, to simulate pH effects of wood ash, or potassium (K) + phosphorus (P) fertilizer to mimic the nutrient effects. After 4.5 months of growth, we measured soil pH, plant biomass, Cd accumulation in shoots and N concentration in the various compartments of the system. Wood ash addition stimulated plant growth, whereas CaO and K + P addition resulted in more moderate increases in biomass. Despite the low concentration of N in the wood ash, plant uptake of N increased in wood ash amendments, probably because wood ash stimulated mineralization of soil organic N. Plant Cd content significantly increased at the highest dose of wood ash. Our results suggest that addition of wood ash significantly stimulates plant growth due to the combined effect of increased pH, elevated nutrient levels and increased N mineralization. Furthermore, despite the rather high Cd content in used wood ash (16.3 mg kg−1), wood ash amendments up to 11 t ha−1 did not result in significantly increased plant uptake of Cd.

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author
; ; ; ; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
keywords
Cadmium, Circular economy, Plant growth, Plant nutrients, Soil pH, Sustainability, Wood ash
in
Environmental and Experimental Botany
volume
185
article number
104424
pages
9 pages
publisher
Elsevier
external identifiers
  • scopus:85101337157
ISSN
0098-8472
DOI
10.1016/j.envexpbot.2021.104424
language
English
LU publication?
no
additional info
Publisher Copyright: © 2021 Elsevier B.V.
id
851e0d47-e315-44b7-a9cd-a79e97908387
date added to LUP
2022-08-26 11:30:33
date last changed
2023-04-28 10:22:32
@article{851e0d47-e315-44b7-a9cd-a79e97908387,
  abstract     = {{<p>Wood ash is a by-product from energy production that can be recycled to forests to regain nutrients and prevent acidification. However, low concentrations of nitrogen (N) in wood ash may reduce its potential positive effect on plant growth. In addition, wood ash can have a high content of toxic heavy metals such as Cd, thus there are concerns that it may increase Cd accumulation in plants. We grew Deschampsia flexuosa (Wavy hair-grass) in pots in acidic nutrient poor forest soil fertilized with different concentrations of wood ash (corresponding to field application of 0, 1.1, 3.3, 11 and 33 t ha<sup>−1</sup>). Additionally, to disentangle the pH and nutrient effects of wood ash application, we included treatments with either CaO, to simulate pH effects of wood ash, or potassium (K) + phosphorus (P) fertilizer to mimic the nutrient effects. After 4.5 months of growth, we measured soil pH, plant biomass, Cd accumulation in shoots and N concentration in the various compartments of the system. Wood ash addition stimulated plant growth, whereas CaO and K + P addition resulted in more moderate increases in biomass. Despite the low concentration of N in the wood ash, plant uptake of N increased in wood ash amendments, probably because wood ash stimulated mineralization of soil organic N. Plant Cd content significantly increased at the highest dose of wood ash. Our results suggest that addition of wood ash significantly stimulates plant growth due to the combined effect of increased pH, elevated nutrient levels and increased N mineralization. Furthermore, despite the rather high Cd content in used wood ash (16.3 mg kg<sup>−1</sup>), wood ash amendments up to 11 t ha<sup>−1</sup> did not result in significantly increased plant uptake of Cd.</p>}},
  author       = {{Johansen, Jesper Liengaard and Nielsen, Maiken Lundstad and Vestergård, Mette and Mortensen, Louise Hindborg and Cruz-Paredes, Carla and Rønn, Regin and Kjøller, Rasmus and Hovmand, Mads and Christensen, Søren and Ekelund, Flemming}},
  issn         = {{0098-8472}},
  keywords     = {{Cadmium; Circular economy; Plant growth; Plant nutrients; Soil pH; Sustainability; Wood ash}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Environmental and Experimental Botany}},
  title        = {{The complexity of wood ash fertilization disentangled : Effects on soil pH, nutrient status, plant growth and cadmium accumulation}},
  url          = {{http://dx.doi.org/10.1016/j.envexpbot.2021.104424}},
  doi          = {{10.1016/j.envexpbot.2021.104424}},
  volume       = {{185}},
  year         = {{2021}},
}