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

The nesting success of waterfowl can be increased by deferred use of perennial forage plant species adjacent to Canadian prairie wetlands for habitat cover. However, the maintenance of plant species diversity and biomass production requires periodic vegetation management such as biomass harvesting. The objective of this study was to determine the quality of forage harvested 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, representing a range from 2 to 4 yr of deferred use. Plant species were described and 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 determined as crude protein (CP), in vitro organic matter digestibility (IVOMD), acid detergent fibre (ADF), neutral detergent fibre (NDF), P and Ca content. Deferral period affected quality, but the response varied by province. For 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) increased 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) more 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 the other provinces. These forage sources will produce medium quality hay for beef cattle production. Deferring native species sites for 2 yr will produce highest biomass yields with the highest cellulosic content for potential bioethanol conversion.