Quality of deferred forage from waterfowl nesting sites on the Canadian prairies

The nesting success of waterfowl can be increased by deferred use of perenn ial forage plant species adjacent to Canadian prairie wetlands for habitat cover. However, the maintenance of plant species diversity and biomass prod uction requires periodic vegetation management such as biomass harvesting. The objective of this study was to determine the quality of forage harveste d from these sites as affected by deferral period (years), cutting height, species type (tame vs. native) and province. Biomass was sampled at 16, 12 and 12 sites in Manitoba, Saskatchewan, and Alberta, respectively, represen ting a range from 2 to 4 yr of deferred use. Plant species were described a nd samples were clipped at 10 and 20 cm cutting height at 8 or 16 transect points per site in late July or early August 1994. Forage quality was deter mined as crude protein (CP), in vitro organic matter digestibility (IVOMD), acid detergent fibre (ADF), neutral detergent fibre (NDF), P and Ca conten t. Deferral period affected quality, but the response varied by province. F or example, IVOMD was 90 g kg(-1) higher at sites with longer deferred use in Saskatchewan, but was similar for Alberta and Manitoba sites. Harvesting at 20 cm height resulted in 24 g kg(-1) greater IVOMD and 9 g kg(-1) incre ased CP averaged across all three provinces. Forage from tame species sites exhibited 70 g kg(-1) higher IVOMD, 49 g kg(-1) greater CP, 0.3 g kg(-1) m ore P and 4.6 g kg(-1) more Ca content than that of native species sites in Alberta but there was no difference between vegetation types at sites in t he ether provinces. These forage sources will produce medium quality hay fo r beef cattle production. Deferring native species sites for 2 yr will prod uce highest biomass yields with the highest cellulosic content for potentia l bioethanol conversion.