Aquatic Plant Control Research Program. Effects of Organic Amendments to Sediment on Freshwater Macrophyte Growth

摘要

The growth of three submersed macorphyte species (Myriophyllum spicatum, Hydrilla verticillata, and Elodea canadensis) and three partially emergent macrophyte species (Sagittaria latifolia, Myriophyllum aquaticum, and Potamogeton nodosus) was examined on a nonamended sediment and on the same sediment amended by additions of five types of vegetative organic matter (two labile and three refractory). With individual amendments, the organic content of the sediment was increased from an initial value of ca. 10 percent to a final value of 15 percent (low-level amendment) and from an initial value of ca. 15 percent to a final value of 20, 25, and 30 percent (high-level amendments). At equal levels of organic matter addition (low-level amendment), macrophyte growth varied with the type of amendment and the species of aquatic macrophyte. Biomass accrual by emergent species as a group was generally greater on all sediments, and was less inhibited than that of submersed species on amended sediments. At the high levels of amendment, the growth of representative submersed and emergent species was severely inhibited on all amended sediments irrespective of amendment type. The inhibitory influence of Hydrilla verticillata of sediment amended by additions of labile organic matter decreased with increasing sediment age relative to time of amendment.