High yielding biomass genotypes of willow (Salixspp.) show differences in below ground biomass allocation.
Willows (Salixspp.) grown as short rotation coppice (SRC) are viewed as a sustainable source of biomass with a positive greenhouse gas (GHG) balance due to their potential to fix and accumulate carbon (C) below ground. However, exploiting this potential has been limited by the paucity of data available on below ground biomass allocation and the extent to which it varies between genotypes. Furthermore, it is likely that allocation can be altered considerably by environment. To investigate the role of genotype and environment on allocation, four willow genotypes were grown at two replicated field sites in southeast England and west Wales, UK. Above and below ground biomass was intensively measured over two two-year rotations. Significant genotypic differences in biomass allocation were identified, with below ground allocation differing by up to 10% between genotypes. Importantly, the genotype with the highest below ground biomass also had the highest above ground yield. Furthermore, leaf area was found to be a good predictor of below ground biomass. Growth environment significantly impacted allocation; the willow genotypes grown in west Wales had up to 94% more biomass below ground by the end of the second rotation. A single investigation into fine roots showed the same pattern with double the volume of fine roots present. This greater below ground allocation may be attributed primarily to higher wind speeds, plus differences in humidity and soil characteristics. These results demonstrate that the capacity exists to breed plants with both high yields and high potential for C accumulation.
Agroecology Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
Jennifer
J
Cunniff
Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, SY23 3EE, UK.
Sarah J
SJ
Purdy
Agroecology Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
Tim J P
TJ
Barraclough
Agroecology Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
March
M
Castle
Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, SY23 3EE, UK.
Anne L
AL
Maddison
Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, SY23 3EE, UK.
Laurence E
LE
Jones
Agroecology Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
Ian F
IF
Shield
Sustainable Soils and Grassland Systems Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
Andrew S
AS
Gregory
Agroecology Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
Angela
A
Karp
Allocation; Biomass; Carbon accumulation; Genotypes; Roots; Willow