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The cultivation of perennial flowering wild plant species like common tansy (Tanacetum vulgare L.) seems promising for increasing biodiversity friendliness in rather monotonous bioenergy cropping systems in Central Europe, particularly on marginal sites. However, it is still unclear for which types of marginal agricultural land common tansy would be suitable and where; as a result, low-risk indirect land-use change biomass production through common tansy could be considered. Therefore, the aim of this study was to gather initial insights into the suitability of common tansy for sandy sites by means of a 6 L-pot experiment. For this purpose, five replicates of three substrates were prepared: Luvisol topsoil (control) from a field site near the University of Hohenheim, Germany; and admixtures of 50 and 83.4weight(wt)% of sand to the control (M1, and M2), respectively. This resulted in varying sand contents of the substrates of 4.7 (control), 53.3 (M1), and 83.0wt% (M2). In autumn 2021, common tansy seeds were collected from mother plants bearing the breeder's indentifier 'Z.8TAV 85/78'. These plants were part of a long-term field trial initiated at Hohenheim in 2014, where common tansy was grown as part of a wild plant mixture. In June 2022, 0.5 g of the seeds were sown in each pot. The pots were placed in outdoor conditions, arranged in a randomized complete block design and watered evenly as required. At harvest in July 2023, significant differences between the substrates in terms of the above- (shoots) and belowground (roots) development of the common tansy seedlings were observed. In M1, common tansy provided notable biomass growth of 56.6% of the control, proving to be potentially suitable for low-input cultivation under sandy soil conditions. However, an even higher share of sand and low nutrient contents in M2 resulted in minor plant development (14.4% of the control). Hence, field trials on sandy soils of about 50wt% of sand in the texture under tailored fertilization and various climatic conditions are recommended. [ABSTRACT FROM AUTHOR]

Due to its ample production of lignocellulosic biomass, Sida hermaphrodita (Sida), a perennial forb, is considered a valuable raw material for biorefinery processes. The recalcitrant nature of Sida lignocellulosic biomass towards pretreatment and fractionation processes has previously been studied. However, Sida is a non-domesticated species and here we aimed at expanding the potential of such plants in terms of their processability for downstream processes by making use of the natural variety of Sida. To achieve this goal, we established a collection comprising 16 different Sida accessions obtained from North America and Europe. First, we asked whether their cell wall characteristics are reflected in genetic distance or geographical distribution, respectively. A genotyping-by-sequencing (GBS) analysis resulting in a phylogenic tree based on 751 Single Nucleotide Polymorphisms (SNPs), revealed a high genetic diversity and a clear separation between accessions collected in North America and Europe. Further, all three North American accessions were separated from each other. Of the eleven European accessions, five form individual groups and six others belong to a single group. Clonal plants of seven selected accessions of American and European origin were produced and cultivated under greenhouse conditions and the resulting plant material was used for in-depth wet-chemical and spectroscopic cell wall characterization. Two accessions with contrasting cell wall characteristics were then selected and processed using the OrganoCat technology. Results of the different product yields and chemical compositions are reported. Overall, cell wall analyses revealed contrasting clusters regarding these main components between the accessions that can be related to genetic and, partly, geographical distance. Phenotypically, the accessions clustered into two groups that are not entirely overlapping with geographical origin. These results can be the basis for a targeted selection or cultivation of Sida accessions for biorefinery approaches. [ABSTRACT FROM AUTHOR]

Biomass from perennial plants can be considered a carbon-neutral renewable resource. The tall wheatgrass hybrid Szarvasi-1 (Agropyron elongatum , hereafter referred to as "Szarvasi") belongs to the perennial Poaceae representing a species, which can grow on marginal soils and produce large amounts of biomass. Several conventional and advanced pretreatment methods have been developed to enhance the saccharification efficiency of plant biomass. Advanced pretreatment methods, such as microwave-assisted pretreatment methods are faster and use less energy compared to conventional pretreatment methods. In this study, we investigated the potential of Szarvasi biomass as a biorefinery feedstock. For this purpose, the lignocellulosic structure of Szarvasi biomass was investigated in detail. In addition, microwave-assisted pretreatments were applied to Szarvasi biomass using different reagents including weak acids and alkali. The produced pulp, hydrolysates, and extracted lignin were quantitatively characterized. In particular, the alkali pretreatment significantly enhanced the saccharification efficiency of the pulp 16-fold compared to untreated biomass of Szarvasi. The acid pretreatment directly converted 25% of the cellulose into glucose without the need of enzymatic digestion. In addition, based on lignin compositional and lignin linkage analysis a lignin chemical model structure present in Szarvasi biomass could be established. [ABSTRACT FROM AUTHOR]

Improving fertility of marginal soils for the sustainable production of biomass is a strategy for reducing land use conflicts between food and energy crops. Digestates can be used as fertilizer and for soil amelioration. In order to promote plant growth and reduce potential adverse effects on roots because of broadcast digestate fertilization, we propose to apply local digestate depots placed into the rhizosphere. We grew Sida hermaphrodita in large mesocosms outdoors for three growing seasons and in rhizotrons in the greenhouse for 3 months both filled with marginal substrate, including multiple sampling dates. We compared digestate broadcast application with digestate depot fertilization and a mineral fertilizer control. We show that depot fertilization promotes a deep reaching root system of S. hermaphrodita seedlings followed by the formation of a dense root cluster around the depot-fertilized zone, resulting in a fivefold increased biomass yield. Temporal adverse effects on root growth were linked to high initial concentrations of ammonium and nitrite in the rhizosphere in either fertilizer application, followed by a high biomass increase after its microbial conversion to nitrate. We conclude that digestate depot fertilization can contribute to an improved cultivation of perennial energy-crops on marginal soils. [ABSTRACT FROM AUTHOR]

During biogas production anaerobic digestion of plant material produces a nutrient-rich residue called digestate. The application of the nutrients present in the digestate should improve soil fertility, particularly in nutrient poor soils, and thus crop yield, promoting the closure of the nutrient cycle. This study evaluated the effect of digestate application on the germination and early stages of plant development since these are the first steps to be considered when studying the benefits on plant growth in low fertility substrates. A greenhouse experiment was conducted to evaluate the effects of three substrates of different texture and fertility (field loam, field sand, sand), as well as type and amount of fertilizer (pure maize digestate vs. inorganic nitrogen/phosphorus/potassium (NPK) fertilizer) on both germination and early plant performance of maize (Zea mays L. subsp. mays). While digestate and NPK fertilizer applications had no significant effect on germination in the two field soils, digestate applications significantly decreased the germination rate in sand (36–82% reduction) due to an increase of surface water repellency. In contrast, for aboveground biomass yield, the most positive fertilization effects of digestate application were found on sand (up to 3.5 times the biomass of the unamended control) followed by field sand (1.5 times), compared to no effect for field loam. Our findings suggest that digestate application have positive fertilization effects in low-fertility substrates, similar to NPK, even though digestate application may have a negative impact on the permeability in sandy substrates that could interfere with germination. [ABSTRACT FROM AUTHOR]

Perennial non-food energy crops are currently discussed as a more sustainable alternative to conventional energy crops like maize. As they can be cultivated on marginal soils, they reduce the risk of land use and food vs. fuel conflicts. In this study, we evaluated the perennial energy crop Sida hermaphrodita for its potential to be cultivated on marginal substrate and conventional agricultural soils over a three-year field and mesocosm experiment at agricultural conditions. Furthermore, we aimed for a closed nutrient loop by fertilizing plants with biogas digestate and using the carbon fraction of the digestate as soil amendment to ameliorate the overall soil fertility. As controls, plants were either untreated or fertilized with an equivalent amount of mineral NPK fertilizer. We found S. hermaphrodita to give highest DM yields of up to 28 t ha −1 under favorable soil conditions when fertilized with mineral NPK. However, on marginal substrate digestate fertilization resulted in a clear biomass yield advantage over NPK fertilization. An increased soil carbon content, water holding capacity and basal soil respiration indicated improved soil fertility in the marginal substrate. These results demonstrate the great potential of S. hermaphrodita to be cultivated on marginal soil in combination with organic fertilization via biogas digestate. [ABSTRACT FROM AUTHOR]

Growing energy crops in marginal, nutrient-deficient soils is a more sustainable alternative to conventional cultivation. The use of energy-intensive synthetic fertilizers needs to be reduced, preferably via closed nutrient loops in the biomass production cycle. In the present study based on the first growing season of a mesocosm experiment using large bins outdoors, we evaluated the potential of the energy plant Sida hermaphrodita to grow in a marginal sandy soil. We applied different fertilization treatments using either digestate from biogas production or a commercial mineral NPK-fertilizer. To further increase independence from synthetically produced N-fertilizers, the legume plant Medicago sativa was intercropped to introduce atmospherically fixed nitrogen and potentially facilitate the production of additional S . hermaphrodita biomass. We found digestate to be the best performing fertilizer because it produced similar yields as the NPK fertilization but minimized nitrate leaching. Legume intercropping increased the total biomass yield by more than 100% compared to S . hermaphrodita single cropping in the fertilized variants. However, it negatively influenced the performance of S . hermaphrodita in the following year. We conclude that a successful establishment of S . hermaphrodita for biomass production in marginal soils is possible and digestate application formed the best fertilization method when considering a range of aspects including overall yield, nitrate leaching, nitrogen fixation of M . sativa , and sustainability over time. [ABSTRACT FROM AUTHOR]