Alfalfa (Medicago sativa L.) overseeding on mature switchgrass (Panicum virgatum L.) stand: biomass yield and nutritive value after the establishment year

Abstract

Perennial crops can positively act on the environment providing a better inter-annual protection of soil cover from water erosion, limiting soil fertility degradation, the risk of nutrient leaching and the exploitation of water for irrigation. Switchgrass (Panicum virgatum L.), a warm-season grass native from North America, has been cultivated for decades as forage crop and only recently as bioenergy crop. Even if several studies reported a positive effect of nitrogen (N) supply on switchgrass yield and quality, potential indirect and direct environmental risks (e.g., eutrophication and greenhouse gas emission) are related to this practice. For this reason grass-legume intercropping can represent a sustainable practice able to increase biomass yield and quality, and at the same time to improve N use efficiency, soil structure and fertility. Based on this, the aim of this study was to evaluate the suitability of switchgrass to Mediterranean environment as forage crop and to improve biomass yield and its nutritional value by intercropping with alfalfa (Medicago sativa L). During spring 2013, in two switchgrass pure stands (varieties Alamo and Blackwell, respectively), alfalfa was established through direct seeding implementing a split-plot experimental design. Our first year results report a positive effect of the intercropping in increasing the total annual yield of the stand, of about 20% with respect to the pure switchgrass stand. However, the presence of alfalfa negatively affected switchgrass yield in the mixture. In both varieties, the crude protein content was higher in the mixture than in the pure switchgrass stands. Conversely, the neutral detergent fibre content in the mixture was lower than in pure switchgrass. Then, our results show that switchgrass-alfalfa intercropping leads to increase the profitability of grassland-based livestock production.

Overseeding oat into limpograss: The effect of trees on animal performance and profitability

“…Grassland-based feedstock is a sustainable way to reduce greenhouse gas emissions associated with animal products (Soussana et al, 2010;Thompson et al, 2023). The inclusion of perennial species such as perennial forage crops and trees has a high potential for storing carbon in soil and trunk and also has a positive impact on the environment by providing all-technique, to improve forage quality and the seasonal distribution of biomass production compared to monocultures (Bambo et al, 2009;Hanish et al, 2022;Mantino et al, 2016). Overseeding cool-season grasses (e.g., black oat (Avena strigosa Schreb), oat (Avena sativa L.), and annual ryegrass (Lolium multiflorum Lam.)…”

“…However, they are mainly grown as monoculture. Studies have described the potential of grass mixtures, for example, those obtained by the overseeding technique, to improve forage quality and the seasonal distribution of biomass production compared to monocultures (Bambo et al., 2009; Hanish et al., 2022; Mantino et al., 2016). Overseeding cool‐season grasses (e.g., black oat ( Avena strigosa Schreb), oat ( Avena sativa L.), and annual ryegrass ( Lolium multiflorum Lam.)…”

The overseeding of two cool-season legumes (Hedysarum coronarium L. and Trifolium incarnatum L.) on switchgrass (Panicum virgatum L.) mature stands increased biomass productivity

“…At present, only few recent researches mainly conducted in the USA have investigated the intercropping of switchgrass with cool-season legumes (Bow et al, 2008;Butler et al, 2013;Ashworth et al, 2015a). Recently in the Mediterranean, preliminary data of alfalfa (Medicago sativa L.) and switchgrass mixture showed an increase of biomass production in mixture than in pure grass stand (Mantino et al, 2016). Overall, the intercropping with legumes can decrease the use of N fertilizer, thus limiting the environmental risks related with nitrogen leaching and NOx soil emissions (Anglade et al, 2015).…”

Potential contribution of Sulla spinosissima (L.) and Sulla pallida (Desf.) as a forage crop for arid pastures rehabilitation

“…2013). Furthermore, agronomic and environmental factors such as grass-legume intercropping(Mantino et al 2016), irrigation treatments(Martiniello et al 2012), the effect of arbuscular mycorrhiza symbiosis(Sabia et al 2015), soil type(Snyman and Joubert 1995) and salinity(Kapulnik and Heuer 1991) and altitude(Mountousis et al 2006), could have a strong effect upon plant yield and quality. Notably, Sulla spinosissima L. at 397 m tends to bloom earlier and produce less forage compared to Sulla pallida Desf.…”