Cutting management of alfalfa‐based mixtures in contrasting agroclimatic regions

Abstract

Cutting schedules affect forage yield, nutritive value, and persistence but few studies have recently assessed the effect of intensive cutting schedules on alfalfa (Medicago sativa L.)-based mixtures. We determined the effects of (a) cutting at early bud vs. early bloom of alfalfa, (b) a fall cut, (c) alfalfa-grass mixture vs. pure alfalfa, (d) one vs. two grasses, and (e) tall fescue (Schedonorus arundinacea [Schreb.] Dumort.) vs. timothy (Phleum pratense L.) in an experiment over four post-seeding years at four sites with four cutting schedules on four alfalfa-based mixtures. Cutting alfalfa at early bud rather than early bloom reduced annual forage dry matter (DM) yield by 2.03 Mg ha −1 and alfalfa contribution to DM yield by 17 percentage units, increased forage total digestible nutrient (TDN) concentration by 44 g kg −1 DM but did not increase estimated annual milk production per hectare. A fall cut did not improve annual forage DM yield and estimated annual milk production per hectare but reduced alfalfa contribution to DM yield. Pure alfalfa resulted in 1.09 Mg DM ha −1 less annual forage DM yield than alfalfa grown with one or two grasses. Two forage grasses with alfalfa compared with just one grass had no effect on forage DM yield and estimated annual milk production per hectare. The response of forage DM yield and estimated annual milk production per hectare to timothy or tall fescue with alfalfa varied with site but forage TDN concentration and alfalfa contribution to DM yield were generally greater with timothy than tall fescue.Abbreviations: ADF, acid detergent fiber; aNDF, neutral detergent fiber assayed with a heat-stable amylase and sodium sulfite; CP, crude protein; DM, dry matter; GDD, growing degree-days calculated using a 5 • C basis; NDFd, in vitro neutral detergent fiber digestibility; PLS, pure live seed basis; TDN, total digestible nutrients; VNIRS, visible and near-infrared reflectance spectroscopy.

Grass–Legume Forage Systems Effect on Phosphorus Removal from a Grassland Historically Irrigated with Reclaimed Wastewater

“…Phosphorus removal is heavily dependent on herbage accumulation, and therefore, the sole use of monoculture legumes may not be a highly effective ameliorator of phosphorus from high P soils in water-limited environments. Bélanger et al [56] reported that alfalfa grown in mixtures with at least one forage grass species had greater herbage accumulation than alfalfa grown alone, and their results were in concurrence with the results of this study. Further, the seeding rate ratio played a key role in herbage accumulation differences among the grass monocultures, and grass-legume mixtures in this study, and a similar observation was made by Adjesiwor et al [57].…”

Perennial forages in cold‐humid areas: Adaptation and resilience‐building strategies toward climate change

“…Under continental cold and humid conditions of northeastern North America, a moderate level of species diversity (about two to seven species) in intensively managed perennial forage stands generally benefits or at least maintains forage yield and reduces weeds (Bélanger et al., 2014, 2020; Deak et al., 2007, 2010; McElroy et al., 2012; Papadopoulos et al., 2012; Sanderson et al., 2005, 2012; Skinner & Dell, 2016; Tracy & Sanderson, 2004) compared to monocultures and/or to less diverse mixtures. In a multi‐criteria optimization study, Goslee et al.…”

“…There is some evidence, although currently limited, that this relationship between species diversity and resilience is also valid for alfalfa‐based mixtures typical of northeastern North America. In eastern Canada, year‐to‐year stability of forage yield in alfalfa‐grass mixtures (with one or two grasses) was greater than in pure alfalfa over four post‐seeding years (Bélanger et al., 2020). In Pennsylvania, lower year‐to‐year variability in forage yield with complex (five or seven species) rather than simple (two or three species) mixtures including alfalfa was shown using the IFSM model (Deak et al., 2010).…”

“…Complementarity mechanisms and positive interactions among species as well as the portfolio effect (variations in the abundance of species in mixture over time) are still present under perturbations (e.g., drought, Bakker et al, 2019;Grange et al, 2021;Lüscher et al, 2022;Volaire et al, 2014) and could become even more important under increased weather variability associated with climate change (Mäkinen et al, 2015). Under continental cold and humid conditions of northeastern North America, a moderate level of species diversity (about two to seven species) in intensively managed perennial forage stands generally benefits or at least maintains forage yield and reduces weeds (Bélanger et al, 2014(Bélanger et al, , 2020Deak et al, 2007Deak et al, , 2010McElroy et al, 2012;Papadopoulos et al, 2012;Sanderson et al, 2005Sanderson et al, , 2012Skinner & Dell, 2016;Tracy & Sanderson, 2004) compared to monocultures and/or to less diverse mixtures. In a multi-criteria optimization study, Goslee et al (2013) found that "ideal" mixtures for pastures in northeastern United States would mostly include an intermediate level of species richness of between three and six species.…”

Modeled performance of forage mixtures and annual crops grown in eastern Canada under climate change

“…Forage yield and nutritive value of pure alfalfa and pure timothy were not assessed in this study as it is not a common practice in eastern Canada to use them in pure stands. Pure alfalfa was shown to have lower forage yield than in mixture with at least one grass species (Bélanger et al., 2020). These evaluations were carried out using IFSM for near future (2020–2049) and distant future (2050–2079) periods, and for two climatically contrasting agricultural areas in eastern Canada.…”