Ensilability of Biomass From Effloresced Flower Strips as Co-substrate in Bioenergy Production.

Jürgen Müller,Juliane Hahn

doi:10.3389/fbioe.2020.00014

Abstract

Flower strips are grown to an increasing degree in order to enhance the ecological value of agricultural landscapes. Depending on their profitable life span and the crop sequence, the strips’ biomass must be mulched after flowering to enable repeated tillage. A promising alternative is the use of the flower strips’ biomass as a co-substrate for biomethanisation – thereby contributing to the climate-friendly generation of energy. This potential bioenergy substrate occurs only seasonally and is commonly produced only in limited quantities at a farm scale. To realize the additional benefit of flower strips as energy suppliers, stock piling of the strips’ biomass is required. However, information about the ensilability of flower strip biomass is still rare. We conducted a 2-year study to analyze the ensilability of pure biomass from effloresced flower strips and mixtures of flower strip biomass with 33 and 67% whole crop maize, respectively. Ensiling took place in 3 l model silos at laboratory scale after chopping the substrate. Before ensiling several chemical characteristics of the biomass stock were determined to assess the substrate’s biochemical ensilability potential (dry matter content, water-soluble carbohydrates, buffering capacity, nitrate content). The process-engineered ensiling success after 90 days was determined based on fermentation patterns. The ensilability potential of the pure flower strip substrates reached modest levels (fermentability coefficients according to Weißbach vary around the threshold of 45). Nevertheless, acceptable silage qualities were achieved under the laboratory conditions (pH ranging from 4.2 to 4.7). Compared to pure flower strip biomass, the addition of maize noticeably improved both the substrate’s biochemical ensilability potential and the quality of real fermented silage. We conclude that a mixture of 33% biomass from flower strips with 67% whole crop maize can be regarded as a recommendable ratio if proper ensiling technology is applied.

Highlights

Two developments characterize the current situation in the agricultural sector: the increasing demand for food (Davis et al, 2016) and the growing importance of bio-based energy production (Hennig et al, 2016)
With more than 40%, the dry matter content was highest in the pure flower strip mixture substrate (FM100)
Since there is little experience with the ensiling capability of flower strip mixture’s substrates, we studied the ensilability of botanically classified and compositionrelated described feedstock from late harvested flower strips as pure substrate or blended with whole-crop maize

Summary

Introduction

Two developments characterize the current situation in the agricultural sector: the increasing demand for food (Davis et al, 2016) and the growing importance of bio-based energy production (Hennig et al, 2016) Both developments are linked via their respective land requirements and are held responsible for the negative effects of intensive land use on biodiversity (Robertson et al, 2012; Tilman and Clark, 2015). In Europe, the support measures under the so-called second pillar of the EU Common Agricultural Policy (CAP) framework have led to a significantly increasing area of flowering strips in many regions (Haaland et al, 2011) recently Depending on their profitable life span and the crop sequence in which they are integrated, the strips’ biomass must be mulched after flowering in late summer in order to enable repeated tillage in early autumn. This technology does not require expensive drying and is most widespread in European rural areas (Capodaglio et al, 2016)

Methods

Results

Discussion

Conclusion