Effects of Beneficial Microbes and Seaweed Extract on the Productivity of Poplar and Switchgrass

Houman Fei, together with a team of researchers from Saint Mary's University in Canada, investigated the use of Azospirillum brasilense N8, Penicillium bilaii, Variovorax paradoxus JM63, and a seaweed extract from Ascophyllum nodosum (ANE) on the growth and nutrient content of three clones of hybrid poplars, Populus x cv. ‘Hill', ‘Okanese' and ‘Walker', and two cultivars of switchgrass (Panicum virgatum), wild type  and the ‘Cave-In-Rock' cultivar.

Researchers found that the biomass accumulation in the poplar clones ‘Okanese' and ‘Walker' was significantly enhanced in treatments with either A. brasilense N8 or P. bilaii. There is also evidence that ANE increased the second-year growth of the clone ‘Walker'. However, there were no significant effects on biomass accumulation in ‘Hill,' indicating a genotype-specific effect.

In switchgrass, an 18% increase in shoot biomass in cv. ‘Cave-In-Rock' inoculated with either A. brasilense N8 or P. bilaii were observed in greenhouse tests. However, there were no significant increases in the field trials. None of the treatments had significant effects on biomass accumulation in the WT switchgrass, hinting another genotype-specific effect.

These results indicate that application of certain beneficial soil microbes and plant-growth promoting substances such as ANE could be used in certain genotypes of biomass feedstock crops to improve sustainable production of these crops.