Monday, November 13, 2006
65-3
Flood Tolerance of Herbaceous Grasses and Legumes.
Robert L. McGraw and James H. Houx III. University of Missouri, 201 Waters Hall, Columbia, MO 65211
The study was initiated to identify potential flood-tolerant herbaceous species for use in floodplains. A flood-tolerance laboratory (FTL) was constructed along Sulphur Creek in the Missouri River floodplain at the Horticulture and Agroforestry Research Center near New Franklin, MO. The FTL has 12 channels, each approximately 6-m wide by 180-m long. Each channel can be independently adjusted for water depth, standing or flowing water, and duration of flooding. The FTL was divided into 3 blocks with 4 treatments per block. The flooding treatments were (1) five-weeks stagnant water, (2) five-weeks flowing water, (3) three-weeks flowing water, and (4) no flooding. Ten grass species and 15 legume species were transplanted into the channels in summer 2003 and 2004. The following spring each year, flooding treatments were applied to a depth of 15 cm. After flooding, plants were allowed to regrow for 4 weeks and the number and dry weight of surviving plants was determined. Results from the two years were similar. Plants survived better in the 3-week flood than the 5-week flood treatment but there was no significant difference between the stagnant and flowing treatments. For the grass species, reed canarygrass performed best across all flood treatments with 97% survival followed by switchgrass at 76%. Redtop, Virginia wild rye, smooth bromegrass, and Kentucky bluegrass had 44, 30, 16, and 14% survival averaged across all treatments. Tall fescue, orchardgrass, and timothy had less than 5% survival and no perennial ryegrass plants survived. The legumes did poorly. Only false wild indigo showed good flood tolerance with an 87% survival. Birdsfoot trefoil had a 17% survived and all other legumes did not survive any treatments either year.