Silphium Perfoliatum Research Articles

Gasification of Cup Plant (Silphium perfoliatum L.) Biomass–Energy Recovery and Environmental Impacts

Biomass from cup plant (Silphium perfoliatum L.) is considered a renewable energy source that can be converted into alternative fuel. Calorific syngas, a promising type of advanced fuel, can be produced through thermochemical biomass gasification. In this study, the suitability of cup plant biomass for gasification was assessed, including the process energy balance and environmental impacts of waste from syngas purification. Silphium perfoliatum L. was cultivated as a gasification feedstock in different conditions (irrigation, fertilization). The experiments were performed in a membrane gasifier. All obtained energy parameters were compared to the biomass yield per hectare. The toxic effects of liquid waste were assessed using tests analyzing germination/seed root elongation of Sinapsis alba. Leachates collected from condensation tanks of a gas generator were introduced to soil at the following doses: 100, 1000 and 10,000 mg kg−1 DM of soil. The usefulness of Silphium perfoliatum L. for gasification was confirmed. The factors of plant cultivation affected the biomass yield, the volume and calorific value of syngas and the amount of biochar. It was determined that the components found in condensates demonstrate a phytotoxic effect, restricting or inhibiting germination and root elongation of Sinapsis alba. Due to this potential hazard, the possibility of its release to the environment should be limited. Most of the biomass is only used for heating purposes, but the syngas obtained from the cup plant can be used to power cogeneration systems, which, apart from heat, also generate electricity.

Responsibility of Certain Biotic Factors for Management Populations of Brevicoryne brassicae L in Cabbage fields

This work was carried out at the experimental farm of the Faculty of Agriculture, Assiut University during the 2017-2018 and 2018-2019 cabbage growing seasons. Evaluation of the seasonal abundance of the cabbage aphid Brevicoryne brassicae L in cabbage fields and responsibility of certain biotic factorsfor managing populations of this insect pest was the cornerstone of this investigation. Cabbage aphid, B. brassicae was found to be active on cabbage plantations and recorded in low numbers (99.71 individuals / 7 Cm2 / leaf / infested plant) at the beginnings of the season (November) with gradual increase until harvesting. Three amongst the six evaluated cabbage cultivars and/or hybrids were appeared as susceptible (S) and harbored so high numbers of the pest. However, the remaining cultivars showed some sort of resistance to this insect pest. The local cultivar (Ganzory) harbored the least aphid numbers and appeared as moderately resistant (MR) cultivar. This finding could be attributed to the antixenosis and/or antibiosis phenomena presented by this local cultivar. Proteins and amino acid contents showed a highly significant positive correlation (r) with B. brassicae populations, however, chlorophyll showed highly significant negative (r). The obtained data reflect the role of the cabbage aphid parasitoid Diaeretiella rapae (McIntosh) to manage B. brassicae populations. Mummified aphids (parasitism rate) before harvesting were found to be equal 6.16-fold of that recorded before ripening stages. High percentages of D. rapae were succeeded to emerge from the mummified B. brassicae with diverse extrusion rates. Multiple increases were recorded on the percentages of infested plants when cabbage undergo toward ripening at the 9th stage till harvesting. No or less existence of unmarketable plants (through the periods of the low infestation)before cup formation and/or plant ripening period was recorded. So, it can be concluded that cabbage cultivar, plant age, and stage in addition to plant metabolites combined with the naturally occurring biological control agent (Aphid parasitoid) can be affected and manage the population trend of cabbage aphid B. brassicae infesting cabbage in the field.

Comparison of maize, permanent cup plant and a perennial grass mixture with regard to soil and water protection

AbstractAgricultural production of biogas maize (Zea mays L.) causes hazards to aquatic ecosystems through high levels of nitrogen (N) inputs. Newly introduced and already established perennial crops such as the cup plant (Silphium perfoliatum L.) and perennial grass mixtures offer the possibility of more environmentally friendly agricultural bioenergy production. The objectives of this field study were to quantify and compare soil mineral N, water infiltration, water runoff, soil erosion and N leaching under maize, permanent cup plant, and a perennial grass mixture. The study was conducted from October 2016 to March 2019 in Braunschweig, Germany. Plots with cup plant and grass mixture exhibited lower mineral N contents than maize, especially between 30 and 90 cm soil depth. Soil water infiltration was significantly different between the three crops. The grass mixture had the highest infiltration rates (6.2 mm/min averaged across 3 years), followed by cup plant (3.6 mm/min) and maize (0.9 mm/min). During wet periods, higher N leaching was found for maize (up to 42 kg N ha−1 year−1) than for cup plant (up to 5 kg N ha−1 year−1) or the grass mixture (up to 11 kg N ha−1 year−1). While runoff and erosion for cup plant and the grass mixture were negligible during the study period, considerable amounts of runoff water and eroded sediment of up to 1.5 Mg ha−1 year−1 were collected from the maize plots despite the near flat terrain of the experimental field. Overall, permanent cup plant proved suitable as a component for energy cropping systems to reduce the risk of N leaching and soil erosion, which is particularly important for the preventive flood protection in view of the more frequent occurrence of high intensity rainfall under climate change conditions.

Two Novel Energy Crops: Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L.—State of Knowledge

Current global temperature increases resulting from human activity threaten many ecosystems and societies, and have led to international and national policy commitments that aim to reduce greenhouse gas emissions. Bioenergy crops provide one means of reducing greenhouse gas emissions from energy production and two novel crops that could be used for this purpose are Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L. This research examined the existing scientific literature available on both crops through a systematic review. The data were collated according to the agronomy, uses, and environmental benefits of each crop. Possible challenges were associated with high initial planting costs, low yields in low rainfall areas, and for Sida hermaphrodita, vulnerability to Sclerotinia sclerotiorum. However, under appropriate environmental conditions, both crops were found to provide large yields over sustained periods of time with relatively low levels of management and could be used to produce large energy surpluses, either through direct combustion or biogas production. Other potential uses included fodder, fibre, and pharmaceutical uses. Environmental benefits included the potential for phytoremediation, and improvements to soil health, biodiversity, and pollination. The review also demonstrated that environmental benefits, such as pollination, soil health, and water quality benefits could be obtained from the use of Sida hermaphrodita and Silphium perfoliatum relative to existing bioenergy crops such as maize, whilst at the same time reducing the greenhouse gas emissions associated with energy production. Future research should examine the long-term implications of using Sida hermaphrodita and Silphium perfoliatum as well as improve knowledge on how to integrate them successfully within existing farming systems and supply chains.

Yields, Calorific Value and Chemical Properties of Cup Plant Silphium perfoliatum L. Biomass, Depending on the Method of Establishing the Plantation

Silphium perfoliatum L. (Silphium) is one of the most promising perennial herbaceous plants, mainly due to its high biomass yield and multiple uses. It can be grown as a fodder, ornamentally, for energy (mainly as a biogas source), and as a honey crop (source of nectar and pollen for pollinators). Despite the considerable qualities of this crop, the Silphium cultivation area in Europe is small. The main limiting factors are the significant costs of plantation establishment and the lack of biomass yield in the first year of cultivation. Considering these aspects, research was undertaken at the Agricultural Experimental Station Lipnik of West Pomeranian University of Technology Szczecin, to assess two methods of establishing a plantation: generative, by sowing seeds (seeds); and vegetative, by transplanting seedlings grown from seeds (planting), on the yield and quality of Silphium biomass attended for combustion and its heating value and chemical composition. In 2016–2019, annual aboveground biomass was harvested after the end of vegetation to obtain the raw material for combustion. The collected dry mass yield (DMY) of Silphium significantly differed between the years and methods of establishing the plantation. The biomass yields increased in the first two years of full vegetation from 9.3 to 18.1 Mg∙ha−1·yr−1, and then decreased in the third year of vegetation to ca. 13 Mg∙ha−1·yr−1 because of drought. Significantly higher DMY was obtained by sowing seeds (ca. 13.9 Mg∙ha−1·yr−1) compared to the planting method (ca. 13.0 Mg∙ha−1·yr−1), due to the higher plant density obtained after the sowing method compared to the planting method. The calorific value in the third year was the highest and amounted to ca. 17.8 MJ·kg−1 DM. The paper also presents changes in soil chemical properties before and after four years of Silphium cultivation.

Effect of Compaction Pressure and Moisture Content on Quality Parameters of Perennial Biomass Pellets

In Poland the use of solid biomass obtained from intentional plantations of energy plants is increasing. This biomass is most often processed into solid fuels. There are growing indications that renewable energy sources, in particular biomass production, will continue to develop, so the better we know the raw material, the more effectively we will be able to use it. The results of tests that determine the impact of compaction pressure on selected quality parameters of pellets made from selected biomass types are presented. Material from plants such as Giant miscanthus (Miscanthus × giganteus Greef et Deu), Cup plant (Silphium perfoliatum L.), Virginia mallow (Sida hermaphrodita (L.) Rusby) was studied. The compaction process was carried out using the SIRIO P400 hydraulic press with a closed chamber with a diameter of 12 mm. Samples were made in four pressures: 131; 196; 262; 327 MPa and three moisture levels: 8%, 11%, 14%. It was found that with increasing compaction pressure and moisture content up to a certain point, the density and durability of the pellets also increased. Each of the materials is characterized by a specific course of changes in the parameters tested.

Water availability affects nectar sugar production and insect visitation of the cup plant Silphium perfoliatum L. (Asteraceae)

AbstractThe perennial cup plant (Silphium perfoliatum L.) is considered as an alternative feedstock to maize for biogas plants. Due to its ecological advantages of an extensive management and function as food resource for pollinators, it can be grown in Ecological Focus Areas (EFAs) since 2018. However, studies at the Julius Kühn‐Institute in Braunschweig (Germany) showed that the assumed advantage of the cup plant of a high drought tolerance could not be confirmed regarding aspects of crop production and yield. We complemented this experiment by assessing how different soil moisture conditions affect the production of floral resources and insect visitation. In 2014, we sampled three irrigated and three rainfed plots of the cup plant. We quantified the nectar volume and sugar mass per inflorescence, the number of inflorescences per plant and calculated the total nectar sugar production. We further counted insect visitation on the inflorescences. Due to reduced numbers of inflorescences per plant and an earlier harvest, the estimated nectar sugar production was 58 kg/ha regarding irrigated and 20 kg/ha regarding rainfed plots. Honeybee visitation per inflorescence was about twice as high in the irrigated plots. Furthermore, the early harvest is a disadvantage for wild pollinators with a late activity period.

Extraction of High-Purity Lignins via Catalyst-free Organosolv Pulping from Low-Input Crops.

A catalyst-free organosolv pulping process was applied to cup plant (Silphium perfoliatum, S), Miscanthus grass (Miscanthus x giganteus, M), and the Paulownia tree (Paulownia tomentosa, P), resulting in high-purity lignins with no signals for cellulose, hemicellulose, or other impurities in two-dimensional heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectra. Different biomass particle sizes used for the organosolv pulping (1.6-2.0 mm (1); 0.5-1.0 mm (2); <0.25 mm (3)) influenced the molecular weight and chemical structure of the isolated lignins. Principal component analysis (PCA) of 1H NMR data revealed a high intergroup variance of Miscanthus and Paulownia lignins, separating the small particle fraction from the larger ones. Furthermore, monolignol ratios identified via HSQC NMR differ significantly: Miscanthus lignins were composed of all three monolignols (guaiacyl (G), p-hydroxyphenyl (H), syringyl (S)), while for Paulownia and Silphium lignins only G and S units were observed (except for P3).

Enzyme-assisted extraction of a cup plant (Silphium perfoliatum L.) Polysaccharide and its antioxidant and hypoglycemic activities

The optimum enzyme-assisted extraction conditions of cup plant (Silphium perfoliatum L.) polysaccharides (CPP) were obtained by response surface methodology (RSM), and were found to be an enzymatic hydrolysis time of 66 min, a liquid-solid ratio of 22 mL/g, pH 5.1, and an enzyme-complex dosage of 1.59 %, allowing a CPP yield of 13.69 %. DEAE-52 cellulose and Sepharose CL-6B columns were used to purify the CPP. A purified polysaccharide component, CPP-1.2, was obtained and further analyzed for its characteristics, antioxidant properties, and hypoglycemic activity. The monosaccharide composition of CPP-1.2 was mannose, galacturonic acid, glucose, galactose, and arabinose with a molar percentage ratio of 2.24:16.34:44.17:24.28:12.97. The 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2-Azino-bis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) radical scavenging abilities of CPP-1.2 (1.0 mg/mL) reached 95.20 % and 93.69 % that of ascorbic acid (1.0 mg/mL), respectively. Moreover, CPP-1.2 presented significantly higher inhibitory properties on the activities of α-amylase and α-glucosidase than acarbose at each concentration tested. These results suggest that CPP-1.2 possesses the potential to be used as an antioxidant and hypoglycemic agent.

The replacement of maize (Zea mays L.) by cup plant (Silphium perfoliatum L.) as biogas substrate and its implications for the energy and material flows of a large biogas plant

AbstractExcessive cultivation of maize (Zea mays L.) as a biogas substrate has fired debate about potential land‐use change effects of bioenergy cropping systems. Cup plant ( Silphium perfoliatum L.) is a perennial biogas crop that provides more environmental services than maize. This study investigated (i) how to replace maize with cup plant as a biogas substrate in a large‐scale biogas plant located in southwest Germany, and (ii) how to optimize the energy and material cycles of such a biogas plant given the new feedstock. The biogas plant produces 1000 m3 biogas per hour with plans for it to be combined with a large dairy farm (1000 dairy units). It was found that the substitution of maize with cup plant as a biogas substrate results in a methane yield reduction of 10% to 20% due to lower biomass yields. However, there exists a strong potential to increase both biomass yields and biogas substrate quality of cup plant by optimizing establishment procedures and better genotypes. Furthermore, cup plant provides food and shelter for open land animals, including birds and insects, and could hence be a suitable alternative to maize for large biogas plants, being more environmentally beneficial. Extracting proteins from cup‐plant biomass could also help replace soy with locally produced protein for feeding cattle. Hydrothermal carbonization is a promising tool for closing nutrient cycles and for extracting phosphate from digestate, but more research is needed before it can be put into practice. © 2020 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Pest potential of Neotephritis finalis (Loew) on Silphium integrifolium Michx., Silphium perfoliatum L., and interspecific hybrids

AbstractNeotephritis finalis (Loew), a fly known as a minor pest of cultivated sunflowers (Helianthus annuus L.), has been observed to attack Silphium spp., which are being evaluated as new crops to produce biomass or edible oil. Infestations of Silphium integrifolium Michx., Silphium perfoliatum L. and their interspecific hybrids were assessed by securing bags over heads late in bloom and counting emerged adult flies ∼30 d later. Effects on seed production were assessed by examining the percent of achenes containing fully developed seeds (i.e., seed set). In 2017, more flies emerged from S. integrifolium and hybrids than from S. perfoliatum, but even high numbers of adult flies emerged per head appeared unrelated to seed set in S. integrifolium. In 2018, far fewer flies were found across Silphium spp., but seed set was similar to 2017. Combined, results indicate that N. finalis is unlikely to limit seed production of Silphium spp.

THE EFFECT OF PURIFIED AMOUNT OF TRITERPENE GLYCOSIDES AND THEIR ENRICHED EXTRACT FROM LEAVES OF SILPHIUM PERFOLIATUM L. ON THE GROWTH AND ACTIVITY OF NITRATE REDUCTASE OF WIN-TER WHEAT PLANTS

The effect of seed treatment with solutions of a purified amount of triterpene glycosides (PATG) containing, as major components, oleanolic acid glycosides – sylphiosides B, C, E, G, and extract (E) enriched with sylphiosides, from Silphium perfoliatum L. (Asteraceae) leaves on growth parameters and nitrate reductase activity (NR, EC 1.6.6.1) of 7-day winter wheat plants (Tritium aestivum L.) was studied. It was shown that, seed treatment with PATG solutions in concentrations of 0.0005 and 0.001% and E in concentrations of 0.2 and 0.4% caused an increase in the length of roots, shoots, wet and dry weight of seedlings compared to the control. The stimulating effect of these concentrations of PATG and E on the total nitrate reductase activity of the roots and leaves of seedlings has been established, and an increase in the stimulating effect of preparations on the activity NR оf against the background of substrate activation of the enzyme potassium nitrate (KNO3) was observed. The greatest increase in the total NR activity of roots and leaves of winter wheat plants was observed when PATG acted at a concentration of 0.001% and E – at a concentration of 0.4%, which amounted respectively 122 and 116%, when adding 1 ml of 50 mM KNO3 solution into the growing medium of plants – 141 and 137% relative to the control. The stimulating effect of exogenous triterpene glycosides on NR activity has been established for the first time. The obtained data allow to theoretically substantiate the possibility of practical use of triterpene glycosides and preparations based on them for the regulation of growth and nitrogen metabolism of plants.

Comparison of different extraction methods of polysaccharides from cup plant (Silphium perfoliatum L.)

The purpose of the present research was to compare the effects of four extraction methods on the extraction yields, physicochemical characteristics, and antioxidant activities of polysaccharides from the cup plant (Silphium perfoliatum L.) (CPPs). The extraction methods included the hot water extraction method (HEM), ultrasonic-assisted extraction method (UEM), enzyme-assisted extraction method (EEM), and the ultrasonic-enzyme-assisted extraction method (UEEM). Four corresponding CPP extracts, HEM-CPPs, UEM-CPPs, EEM-CPPs, and UEEM-CPPs, were obtained. The results indicated that there were notable differences between the extraction methods regarding the yield, average molecular weight, uronic acid content, monosaccharide proportions, and the antioxidant activities of the CPPs. HEM-CPPs were extracted with the lowest yield (6.44%). EEM-CPPs had the largest extraction yield (9.87%) and the most notable antioxidant abilities of ferric reducing power and free radical scavenging activity. According to correlation analysis, the higher antioxidant abilities of EEM-CPPs might be due to their smaller average molecular weight and a higher content of uronic acid than those of the other extracted CPPs. Therefore, EEM could serve as a promising technique for extracting CPPs.

Floral resources provided by the new energy crop, Silphium perfoliatum L. (Asteraceae)

Flower-visiting insects are important crop pollinators, but their populations in agricultural landscapes are declining. One reason is the decreasing quantity and quality of floral resources. Deterioration of the situation caused by an increasing production of energy crops like maize, a pollen-only resource, may be mitigated by alternative crops such as Silphium perfoliatum L., which produces pollen and nectar over a long-lasting flowering period (July–September). The aim of this study was to assess the floral resources of S. perfoliatum. We calculated pollen grains and nectar sugar mass per inflorescence as well as inflorescences per plant using experimental plots and commercial fields in Germany. In addition, we analyzed free and protein-bound amino acids in pollen as well as sugars and free amino acids in nectar. The amount of pollen and nectar sugar per inflorescence decreased with increasing stem branching. The production of pollen and nectar sugar, however, was greatest in the second half of August due to the high number of inflorescences per plant at that stage. About half of the farmers harvested S. perfoliatum before the end of flowering to gain higher methane yields. With an early harvest around the beginning of September about one sixth of total pollen and one fifth of total nectar sugar production were lost to pollinators. Pollen and nectar showed high amounts of certain essential amino acids, particularly histidine, but total amino acids were low in concentration. Hence, S. perfoliatum should be complemented with different bee fodder plants to ensure a well-balanced diet.

Chemical Composition and Biogas Formation potential of Sida hermaphrodita and Silphium perfoliatum

Biogas production and use is one of the pillars of the EU strategy for fossil fuels replacement via renewable energies. In Poland, the most commonly used crop for biogas production is maize. There are many factors limiting the cultivation of this crop, which is why alternative plants are sought. The aim of the present paper was to assess the effect of establishing a plantation using seeds, seedlings, and various harvest dates on biogas production from Silphium perfoliatum L. (Silphium) and from two phenotypes of Sida hermaphrodita L. Rusby (Sida). Harvesting was conducted in the second (2017) and third year of crop growth (2018). These crops were harvested in June and at the beginning of October as a two-cut strategy. Additionally, Silphium was harvested in early autumn as a one-cut strategy. Specific biogas yield (SBY) and specific biomethane yield (SMY) were estimated using the modified Baserga method. The biogas yield per hectare (BY) was calculated. The crop species, method of establishing a plantation, as well as the date and the number of harvests had a significant effect on the content of the selected chemical components; however, significant differences in terms of SBY were not found for the two-cut strategy. In the case of Silphium, approximately 40% more BY was produced for the two-cut strategy compared to the one-cut strategy. The BY was found to be significantly affected by the biomass yield; markedly higher BY can be obtained from Silphium and the average amount obtained in one year was 8598 m3 ha-1 while 4759 m3 ha-1 was obtained from Sida.

Improving the Ecological Performance of Miscanthus (Miscanthus × giganteus Greef et Deuter) through Intercropping with Woad (Isatis tinctoria L.) and Yellow Melilot (Melilotus officinalis L.)

Miscanthus is a promising high-yielding and low-input perennial biomass crop. However, as miscanthus does not produce nectar, it provides less support for pollinators than other perennial biomass crops, such as cup plant, Virginia mallow, or wild plant mixtures. This study discusses whether miscanthus could be intercropped with flower-rich biennial wild plants to further enhance its ecological functioning. In 2017, a demonstration plot was established in southwest Germany with two miscanthus intercropping regimes: woad (WAM) and yellow melilot (YAM). Both woad and melilot reached full bloom in 2018, the second year of cultivation. The flowering period of woad started and ended earlier than that of melilot. Woad remained harvestable until spring 2019, whereas the aboveground melilot was destroyed by brown hare in autumn 2018. However, the shed seeds of melilot reemerged homogeneously in 2019. The miscanthus developed better in YAM than WAM. This was most likely due to (i) stronger competition for water, nutrients, and light in WAM and (ii) nitrogen fixation advantage in melilot. These results indicate that the ecological performance of miscanthus could be improved by intercropping with melilot. Thus, we propose to further investigate the effects of intercropping on both the productivity and quality of miscanthus biomass.

Methane yield and species diversity dynamics of perennial wild plant mixtures established alone, under cover crop maize (Zea mays L.), and after spring barley (Hordeum vulgare L.)

AbstractThe cultivation of perennial wild plant mixtures (WPMs) in biogas cropping systems dominated by maize (Zea mays L.) restores numerous ecosystem functions and improves both spatial and temporal agrobiodiversity. In addition, the colorful appearance of WPM can help enhance landscape beauty. However, their methane yield per hectare (MYH) varies greatly and amounts to only about 50% that of maize. This study aimed at decreasing MYH variability and increasing accumulated MYH of WPM by optimizing the establishment method. A field trial was established in southwest Germany in 2014, and is still running. It tested the effects of three WPM establishment procedures (E1: alone [without maize, in May], E2: undersown in cover crop maize [in May], E3: WPM sown after whole‐crop harvest of spring barley [Hordeum vulgare L.] in June) on both MYH and species diversity of two WPMs [S1, S2]). Mono‐cropped maize and cup plant (Silphium perfoliatum L.) were used as reference crops. Of the WPM treatments tested, S2E2 achieved the highest (19,296 , 60.5% of maize) and S1E1 the lowest accumulated MYH (8,156 , 25.6% of maize) in the years 2014–2018. Cup plant yielded slightly higher than S2E2 (19,968 , 62.6% of maize). In 2014, the WPM sown under maize did not significantly affect the cover crop performance. From 2015 onward, E1 and E2 had comparable average annual MYH and average annual number of WPM species. With a similar accumulated MYH but significantly higher number of species (3.5–10.2), WPM S2E2 outperformed cup plant. Overall, the long‐term MYH performance of WPM cultivation for biogas production can be significantly improved by undersowing with maize as cover crop. This improved establishment method could help facilitate the implementation of WPM cultivation for biogas production and thus reduce the trade‐off between bioenergy and biodiversity.

Assessment of a single application of sewage sludge on the biomass yield of Silphium perfoliatum and changes in naturally acid soil properties

Assessment of a single application of sewage sludge on the biomass yield of Silphium perfoliatum and changes in naturally acid soil properties

Bioenergy from Periodically Waterlogged Cropland in Europe: A First Assessment of the Potential of Five Perennial Energy Crops to Provide Biomass and Their Interactions with Soil

Harvesting of silage maize in late autumn on waterlogged soils may result in several ecological problems such as soil compaction and may subsequently be a major threat to soil fertility in Europe. It was hypothesized that perennial energy crops might reduce the vulnerability for soil compaction through earlier harvest dates and improved soil stability. However, the performance of such crops to be grown on soil that are periodically waterlogged and implications for soil chemical and microbial properties are currently an open issue. Within the framework of a two-year pot experiment we investigated the potential of the cup plant (Silphium perfoliatum L.), Jerusalem artichoke (Helianthus tuberosus), giant knotweed (Fallopia japonicum × bohemica), tall wheatgrass (Agropyron elongatum), and reed canary grass (Phalaris arundinacea) for cultivation under periodically waterlogged soil conditions during the winter half year and implications for soil chemical and biological properties. Examined perennial energy crops coped with periodical waterlogging and showed yields 50% to 150% higher than in the control which was never faced with waterlogging. Root formation was similar in waterlogged and non-waterlogged soil layers. Soil chemical and microbial properties clearly responded to different soil moisture treatments. For example, dehydrogenase activity was two to four times higher in the periodically waterlogged treatment compared to the control. Despite waterlogging, aerobic microbial activity was significantly elevated indicating morphological and metabolic adaptation of the perennial crops to withstand waterlogged conditions. Thus, our results reveal first evidence of a site-adapted biomass production on periodical waterlogged soils through the cultivation of perennial energy crops and for intense plant microbe interactions.

Mitigating the biodiversity footprint of energy crops – A case study on arthropod diversity

Rising demand for renewable resources has increased silage maize (Zea mays L.) production characterized by intensive soil management, high fertilizer and pesticide inputs as well as simplified crop rotations. Advantages of renewable biomass production may thus be cancelled out by adverse environmental effects. Perennial crops, like cup plant (Silphium perfoliatum L.), are said to benefit arthropods. Substituting silage maize could hence increase biodiversity and foster ecosystem services.This study aimed at comparing the attractiveness of both crops to arthropods, which are either flower-visiting or active in the crop canopy. Further, results were scaled to the landscape level to optimize crop partitioning concerning yields and species diversity.A field experiment with conventionally tilled annual and perennial no-tilled crops was established in 2015 near Munich (Germany). The crops chosen were insect-pollinated cup plant and wind-pollinated maize. Arthropods were sampled between June and September 2016. Four replicated UV-active pan traps, consisting of three bowls each, were used to catch arthropods at the actual crop height on five sampling dates. The collected arthropods were counted and taxonomically determined.In total 3810 individuals (Arachnida: 52; Insecta: 3758) from 9 orders (115 taxonomic groups) were collected. Silage maize mostly showed lower diversity values, indicating higher biodiversity in cup plant. However, the differences were small. Nevertheless, cup plant harbored more pollinators and parasitoids. Finding an optimal combination of both crops based on diversity gains is thus not straightforward. However, integrating cup plant to silage maize production systems allows increasing arthropod diversity by means of moderate yield reduction.