Yield and nutritive value of grazed complex legume–grass mixtures under increasing nitrogen application rates

Abstract

Complex pasture mixtures are advantageous, but little information exists on the best forage species and nitrogen (N) management in eastern Canada. We compared under mob stocking four complex mixtures of one of two legume species [alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus corniculatus L.)] plus one of two grass mixes [No. 1 — timothy (Phleum pratense L.), meadow fescue (Schedonorus pratensis (Huds.) P. Beauv.), reed canarygrass (Phalaris arundinacea L.), and Kentucky bluegrass (Poa pratensis L.); No. 2 — tall fescue (Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.), meadow bromegrass (Bromus biebersteinii Roem. and Schult.), reed canarygrass, and Kentucky bluegrass] under three N application rates at three sites over the first three post-seeding years. Legume species had little effect on most forage attributes mainly because of their low contribution to forage dry matter (DM) yield (<30%) in second and third years. The grass mix with tall fescue and meadow bromegrass (No. 2) yielded similar or slightly better than the one with timothy and meadow fescue (No. 1) but tended to have a greater neutral detergent fibre concentration, and lower N and total digestible nutrient concentrations. Nitrogen fertilization increased forage DM yield only in second and third years when the legume contribution to forage DM yield was <30%, and it increased N concentration and decreased nonstructural carbohydrate concentration. These results highlight the challenge of maintaining legume species in rotationally grazed pastures of eastern Canada and confirm recommendations of applying no or little N fertilizer on grazed legume–grass mixtures when the legume contribution to forage DM yield is >30%.

Feasibility of using phytoremediation biomass for sustainable biofuel production via thermochemical conversion

“…In the second year, herbaceous plant species provided three harvests, which yielded 16 233 kg ha –1 of dry biomass in total. Based on the literature and common agricultural practices, herbaceous biomass output ranges from 3870 to 10 320 kg ha –1 when grown on clean (noncontaminated) soil 20–22 . It is likely that fertilization with mineral and organic fertilizers as well as using bacterial additives provided good conditions for well selected plant species, so a harvest higher than in common agricultural practices was obtained 23 …”

“…Based on the literature and common agricultural practices, herbaceous biomass output ranges from 3870 to 10 320 kg ha -1 when grown on clean (noncontaminated) soil. [20][21][22] It is likely that fertilization with mineral and organic fertilizers as well as using bacterial additives provided good conditions for well selected plant species, so a harvest higher than in common agricultural practices was obtained. 23 In the case of Serbia (case study 2), rapeseed provided a total dry biomass output of about 10 000 kg ha -1 in the first growing season and 2650 kg ha -1 of seed in the second growing season; the dry biomass yield was about 8000 kg ha -1 .…”

Legume addition to alfalfa‐based mixtures improves the forage energy to protein ratio

“…Overall, the establishment of BT across environments was lower than expected and its proportion in botanical composition was low in the first 2 post‐seeding years. In eastern Canada, BT is recognized as a slow establishing species (Bélanger, Tremblay, Papadopoulos, et al., 2020). Even if average proportions of added legume species in botanical composition were different from the expected proportions based on seeding rates, a gradient of proportions was observed as intended for each legume species.…”