The Effect of the Invasive Plant Species Lupinus polyphyllus Lindl. on Energy Recovery Parameters of Semi-Natural Grassland Biomass

Abstract

Biodiversity of semi-natural grasslands is increasingly endangered by successful invasive plant species such as the legume Lupinus polyphyllus Lindl. In order to contain the propagation of this plant species, early and regular harvesting needs to be applied. Therefore, a form of utilization for the harvested biomass has to be developed. One opportunity could be the use of the biomass as a feedstock for biogas and solid fuel production. This study investigates the effect of L. polyphyllus on the nutrient and mineral composition in a mixture series with semi-natural grassland biomass and examines the changes in nutrient and mineral content through hydrothermal conditioning and mechanical dewatering of silage. Untreated lupine-invaded biomass has higher N and Mg concentrations, but lower Cl, K and S concentrations compared to the semi-natural grassland biomass. The mineral concentrations in the biomass exceeded recommendations for combustion. However, with the proposed pre-treatment of hydrothermal conditioning and subsequent dewatering, both lupine-containing and lupine-free semi-natural grassland biomass could achieve adequate values for combustion, given that a state-of-the-art combustion technique is used, including measures to reduce emissions of NO x and particulate matter. Thus, solid fuel production through hydrothermal conditioning and mechanical separation may offer a practical solution for the containment of lupine or other invasive species in semi-natural grasslands and may constitute an important element for sustainable bioenergy production.

Invader presence disrupts the stabilizing effect of species richness in plant community recovery after drought

“…Consequently, the overall stability of the native versus the invader communities may be inferred by two different mechanisms but might ultimately lead to stable—in terms of sheer biomass production—grassland communities (Wilsey et al, 2014). However, both invasive species tested in this study are pasture weeds and their presence might lead to a reduction in fodder value and thus, to economic losses (since the quality of hay production is reduced due to the presence of those species) especially if they occupy large parts of the affected grasslands (Bossdorf, Lipowsky, & Prati, 2008; Hensgen & Wachendorf, 2016). Additionally, invader presence in semi‐natural grasslands will certainly lead to significant change with respect to species richness, habitat provision, nutrient cycling, and water regulations (Klinger et al, 2019; Ramula & Sorvari, 2017; Thiele et al, 2010).…”

Germination of the invasive legume Lupinus polyphyllus depends on cutting date and seed morphology

“…In invaded habitats, L. polyphyllus is capable of overgrowing and shading the underlying vegetation and may cause a considerable decline in the richness of small species (Thiele et al 2010;Hiltbrunner et al 2014), while promoting the spread of tall-growing, nitrogen-demanding vegetation (Otte and Maul 2005). Meadows invaded by this species provide hay of low fodder quality, because of its high water-content and the presence of alkaloids in L. polyphyllus (Hensgen and Wachendorf 2016).…”

Remote sensing data fusion as a tool for biomass prediction in extensive grasslands invaded by L. polyphyllus

“…Lupines have a comparably complex vertical structure with overlapping leaves leading to occlusion of leaves and potential saturation of the biomass-reflectance relationship. As lupine plants usually have higher water contents than the surrounding grass vegetation (Hensgen and Wachendorf, 2016), it seems reasonable, that our machine learning model, based on spectral features, was able to incorporate this relationship.…”