149-3 Sweet Pearl Millet, Sweet Sorghum, and Corn As Bioenergy Crops in Eastern Canada: Learning From the Roots.

See more from this Division: SSSA Division: Soil & Water Management & Conservation
See more from this Session: Bioenergy Production and Environmental Consequences

Monday, November 4, 2013: 1:45 PM
Marriott Tampa Waterside, Grand Ballroom J

Marie-Noelle Thivierge, Agriculture & Agri-Food Canada, Quebec, QC, CANADA, Anne Vanasse, D├ępartement de phytologie, Laval University, Ste Foy, QC, CANADA, Denis Angers, Quebec Research and Development Centre, Agriculture & Agri-Food Canada, Qu├ębec, QC, Canada, Martin Chantigny, Soils and Crops Research and Development Centre, Agriculture & Agri-Food Canada, Quebec, QC, CANADA and Philippe Seguin, 21111 Lakeshore Rd., McGill University, Ste-Anne-de-Bellevue, QC, CANADA
Abstract:
Sweet pearl millet (Pennisetum glaucum [L.] R. BR.) (SPM) and sweet sorghum (Sorghum bicolor [L.] Moench) (SS) are annual C4 grasses that could be interesting alternatives to corn (Zea mays [L.]) for ethanol production in Eastern Canada. The nitrogen (N) requirements of SPM and SS are considerably lower than for corn, suggesting a greater efficiency in soil- and fertilizer-N uptake. Since it is known that fine roots are the main pathway for plant nutrient uptake, differences in root morphology could partly explain this variable N uptake efficiency.

In a randomized block design, we compared the root systems of SPM (hybrid CSSPM7), SS (hybrid CSSH45), and corn (hybrid DKC 43-27) during two growing seasons on a well-drained sandy loam near Quebec City, Canada. Composite soil cores (8 cm diameter, 30 cm depth) were taken in each plot on the row and on the inter-row. Roots were separated from soil using a hydropneumatic elutriation system, red dyed, and scanned. Image analysis was performed with the software WinRhizo (Regent Instrument Inc., Quebec, Canada).

The ash-free root biomass was greater for corn and SS (5043 kg ha-1 and 4632 kg ha-1) than for SPM (2728 kg ha-1) (P<0.001). However, the total root length showed an opposite trend with 72 km m-3 for SPM, and only 47 km m-3 and 41 km m-3 for SS and corn respectively (P<0.001). The three crops also differed in the proportion of total root surface accounted for by fine roots of diameter < 0.2 mm. This proportion was larger for SPM (28% of total root surface) than for SS (24%) and corn (19%) (P<0.001). Other hypotheses to explain differences in N uptake must be investigated. Nevertheless, an improved knowledge of root systems of bioenergy crops is essential, in particular in evaluating their contribution to soil organic carbon.

See more from this Division: SSSA Division: Soil & Water Management & Conservation
See more from this Session: Bioenergy Production and Environmental Consequences