2 Stage Anaerobic Digestion of Post Extracted Algae Residue (PEAR) of Algae to Generate Biohythane

The elemental composition of woody biomass has important consequences for both energy conversion processes and agronomic management of nutrient budgets. We evaluated the effects of genotype, environment and their interaction on elemental concentrations in shrub willow. Samples from six genotypes in four trial locations were separated into bark and wood, and analyzed for C, N and H by combustion and for elemental composition by ICP-OES. An additional set of whole biomass samples for the six genotypes from six additional trial locations were also analyzed, totaling 252 total independent observations. Generally Salix purpurea genotypes had high N, Mg and Fe concentrations in bark, whereas S. miyabeana genotypes had high Ca concentrations in both bark and wood. Hybrids between these two species displayed intermediate values in elemental composition, suggesting an additive mode of inheritance for these traits. Multivariate analyses of the broader suite of biomass samples showed strong environmental effects on elemental composition, but there were a number of significant genotype × environment interactions. Nutrient export rates at harvest were largely a function of yield, but some genotypes showed signs of luxury uptake when N was abundant. These results showed important genotype-specific preferences in nutrient uptake, which may need to be addressed in nutrient management plans. Our test sites did not include heavy metal contaminated soils, but these data suggest a capacity to exploit existing genetic resources for improving phytoremediation applications and for development of effective riparian buffer strips to reduce excess nutrient export.