Erosion control and soil improver
Birdsfoot trefoil provides good soil cover, particularly if associated with tall fescue or a small-grain crop such as barley or oats (Hannaway et al., 2004; Hall et al., 1993). Birdsfoot trefoil can be sown along roadsides to prevent wind and water erosion (Bush, 2002). Birdsfoot trefoil is an N-fixing legume. When it makes up more than 30% of a mixed stand, it provides enough N to the companion grass to sustain its growth and no N fertilizer is needed (Hall et al., 1993). Birdsfoot trefoil was successfully used in soil reclamation (china clay sand wastes) in England where it significantly increased the yield and protein content of its companion grass (Jefferies et al., 1981).
Wildlife habitat
Birdsfoot trefoil provides good cover for wildlife (Bush, 2002). It is a good source of pollen for bees and bumble bees (Bush, 2002; Brian, 1951). Its flowers produce abundant and concentrated nectar and it is considered a valuable honey plant in North America (Canpolin, 2012).
CH4 and N emissions
The condensed tannins in birdsfoot trefoil elicit reductions in CH4 emissions and urinary N in dairy cattle (Woodward et al., 2004; Williams et al., 2011). Though this reduction is partly offset by an increase in faecal N, it favours a reduction of N leaching and volatilization, which contributes to the reduction of eutrophication and greenhouse gas emissions (Aufrère et al., 2012).