BMP testingEnergy crops and whole-crop plants (WCS)
Cup plant — BMP: 8 studies, weighted mean 257 m³ CH₄/t VS
Cup plant (silphium) is a perennial energy crop from North America, grown as an alternative to maize. The dataset covers different harvest dates from several German studies.
rating: goodCH₄ ≈ 52 % (estimate)
Photo JackyM59 / Wikimedia Commons, licence CC BY-SA 4.0, source file; changes: cropping
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- Weighted mean
- 257m³ CH₄/t VS
- Range
- 232–282m³ CH₄/t VS
- Records
- 8studies
- Publications
- 2sources
- Temperatures
- 37 °C, 38 °Cof the test
Methane in biogas
Medium methane content · ≈ 5.2 kWh/m³ of biogas
estimate from the substrate type The collected studies contain no measurement. The interval follows from the approximate composition (carbohydrate-dominated (no protein or fat characteristics)) and the yields of compound groups according to FNR.
Rating for biogas plants
good — editorial rating for biogas plantsStable, usually accepted without a fee
Potential per tonne of fresh matter: high (61 m³ CH₄/t); no particular threats to stability. Handling costs: fibres, floating layer.
Why? Rating factors
Potential per tonne +2
- +2potential 61 m³ CH₄/t fresh matter (BMP 257 × DM 26.9 % × VS 88.2 %)
Process stability 0
- 0no factors
Handling and costs −0.5
- −0.5fibres, floating layer — shredding and intensive mixing
Total points: 1.5 · thresholds: ≥ 2.5 very good, ≥ 1 good, below — neutral; negative with cumulative process risk.
Add to the co-digestion calculator CSV data
BMP curves from 8 studies
Weighted mean Individual records
Dashed lines are a model curve (first-order kinetics, B(t) = B₀·(1 − e−kt)); the end point comes from the publication. All curves are model curves.
Cumulative methane production over the test [m³ CH₄/t VS]. The thick line is the weighted mean of all records (257); dots mark the end values given in the publications. Point at the chart to read values; click a legend item to hide or show a record.
Records and sources
Download CSV| Source | BMP m³ CH₄/t VS | Temperature | Sample | Curve |
|---|---|---|---|---|
| Mast et al. (2014) · 1 DOI | 232 | 37 °C · mesophilic | cup plant | end point (model curve) |
| Mast et al. (2014) · 2 DOI | 248 | 37 °C · mesophilic | cup plant | end point (model curve) |
| Mast et al. (2014) · 3 DOI | 256 | 37 °C · mesophilic | cup plant | end point (model curve) |
| Mast et al. (2014) · 4 DOI | 275 | 37 °C · mesophilic | cup plant | end point (model curve) |
| Ruf i Emmerling (2018) · 1 DOI | 236 | 38 °C · mesophilic | cup plant · pretreatment: particle size reduction/sample preparation (MY-D: physical treatment) | end point (model curve) |
| Ruf i Emmerling (2018) · 2 DOI | 250 | 38 °C · mesophilic | cup plant · pretreatment: particle size reduction/sample preparation (MY-D: physical treatment) | end point (model curve) |
| Ruf i Emmerling (2018) · 3 DOI | 273 | 38 °C · mesophilic | cup plant · pretreatment: particle size reduction/sample preparation (MY-D: physical treatment) | end point (model curve) |
| Ruf i Emmerling (2018) · 4 DOI | 282 | 38 °C · mesophilic | cup plant · pretreatment: particle size reduction/sample preparation (MY-D: physical treatment) | end point (model curve) |
| Weighted mean | 257 | arithmetic mean 257, SD 19 | ||
Typical composition
- Dry matter (DM)
- 26.9% (range 20.8–39)
- Volatile solids (VS)
- 88.2 % DM (range 87.1–93.2)
Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: MY-D); dry matter: 7 determinations, volatile solids: 4 determinations.
Sources: Mast et al. (2014); Ruf et al. (2018).
The composition of the raw material varies between batches — for plant calculations use an analysis of your own sample. The calculator inserts typical values automatically.
Process properties
Advantages
- Methane potential in the database: weighted mean 257 m³ CH₄/t VS (median 253; range 232–282; 8 records from 2 sources).
Drawbacks and risks
- Yield depends on the harvest date (Mast 2014).
Co-digestion — what to combine it with, what to watch out for
- combines well
group: Animal excreta (slurry, manure, poultry litter)
Co-digestion with excreta (slurry/solid manure) is the standard arrangement for plant biomass: they supply alkalinity and microflora.[1][2]
Dosing
No source-based dose limits.
Practical requirements
- Ensiling makes it possible to store seasonal biomass; properly ensiled plants (in the study maize, sorghum, forage rye, triticale) can be stored for up to a year without loss of methane production (Herrmann et al. 2011).
Sources of the process data
- Haag, N.L.; Nägele, H.J.; Reiss, K.; Biertümpfel, A.; Oechsner, H. (2015) Methane formation potential of cup plant (Silphium perfoliatum). Biomass and Bioenergy 75, 126–133
- Weiland, P. (2010) Biogas production: current state and perspectives. Applied Microbiology and Biotechnology
- Hendriks, A.T.W.M.; Zeeman, G. (2009) Pretreatments to enhance the digestibility of lignocellulosic biomass. Bioresource Technology
- Mast, B.; Lemmer, A.; Oechsner, H.; Reinhardt-Hanisch, A.; Claupein, W.; Graeff-Hönninger, S. (2014) Methane yield potential of novel perennial biogas crops influenced by harvest date. Industrial Crops and Products 58, 194–203
- Ruf, T.; Emmerling, C. (2018) Site-adapted production of bioenergy feedstocks on poorly drained cropland through the cultivation of perennial crops. A feasibility study on biomass yield and biochemical methane potential. Biomass and Bioenergy 119, 429–435
- Herrmann et al. (2011). Effects of ensiling, silage additives and storage period on methane formation of biogas crops. Bioresour. Technol.
The co-digestion calculator will assess a specific mixture containing this substrate.
What it is and where it comes from
Cup plant (Silphium perfoliatum) originates from North America, but has been grown in Europe for years, especially in Germany, as a perennial energy crop and an alternative to maize. It forms tall, strong stems and flowers profusely, providing forage for insects. A plantation can be used for more than a dozen years. The dataset contains records from several studies, from different harvest dates, under mesophilic conditions.
Properties relevant to digestion
Silphium biomass is stem-and-leaf material with a moderate fibre share. When harvested in full season, the stems are already fairly lignified, which lowers digestibility compared with young green forage. Ensiling is possible and practised, but care must be taken to achieve a suitable dry matter content. The material requires chopping. There are no significant inhibitors at typical shares in the ration, but the results are lower than for maize silage, which is a trade-off in favour of environmental benefits. Yield in the first years after establishing the plantation is lower.
How to read the spread of results
The spread in the dataset results primarily from harvest date and plantation age, as well as from site and fertilisation. The studies apply somewhat different methodologies (different temperatures, inocula, substrate-to-inoculum ratios). Some records come from a single series, so they are not fully independent. The dataset therefore reflects the range of results for the conditions examined in these studies, and not for every plantation in other regions.
In biogas plant practice
Silphium makes sense on farms that value ecological benefits and the reduction of annual cropping, accepting a lower energy yield than maize. Harvesting with a forage harvester, ensiling and dosing in the mix do not differ from other plant silages. It is important to plan the costs of establishing the plantation and the period needed to reach full yield. Before deciding, it is worth checking the available support for perennial crops and carrying out a BMP test on material from your own field. At the same time, the profitability analysis must take into account the cost of planting material, which is higher than for maize seed, and the period needed to reach full yield. For some farms, payments for perennial crops or environmental benefits, where applicable, are also an important argument.
Methodology in brief
BMP is the amount of methane obtained from volatile solids (VS) in a batch test, given in m³ CH₄ per tonne of VS (numerically the same as NmL CH₄/g VS in the publications) and converted to normal conditions (0 °C, 101.325 kPa). The weighted mean gives each publication a total weight of 1, split equally between its results for the substrate — a paper testing twenty varieties does not outweigh a paper with a single sample. In inter-laboratory programmes the unit is the laboratory (total weight 1), and within it the weight of a test grows with the number of bottles (replicates). Results after pretreatment (e.g. thermal, chemical, enzymatic) are shown separately and are not included in the mean.
Solid lines are curves measured in the tests. Where a publication gives only the final result, we draw a first-order kinetic model, B(t) = B₀·(1 − e−kt): only the end point comes from the publication, and the shape of the curve serves purely as visualisation — do not read the production on a particular day from it. For this substrate k = 0.085 d−1 was assumed (median of rate constants k reported in the sources and/or fitted to the mean measured curves).
The statistics describe the spread of published results — a descriptive compilation, not a meta-analysis or a guarantee of plant yield.
Results after pretreatment (8) — excluded from the mean
| Source | BMP m³ CH₄/t VS | Pretreatment | Sample |
|---|---|---|---|
| Haag et al. (2015) | 250 | physical-enzymatic | Silphium perfoliatum |
| Haag et al. (2015) | 228 | physical-enzymatic | Silphium perfoliatum |
| Haag et al. (2015) | 256 | physical-enzymatic | Silphium perfoliatum |
| Haag et al. (2015) | 248 | physical-enzymatic | Silphium perfoliatum |
| Haag et al. (2015) | 260 | physical-enzymatic | Silphium perfoliatum |
| Haag et al. (2015) | 254 | physical-enzymatic | Silphium perfoliatum |
| Haag et al. (2015) | 255 | physical-enzymatic | Silphium perfoliatum |
| Haag et al. (2015) | 251 | physical-enzymatic | Silphium perfoliatum |
Bibliography
- Mast, B.; Lemmer, A.; Oechsner, H.; Reinhardt-Hanisch, A.; Claupein, W.; Graeff-Hönninger, S. (2014). Methane yield potential of novel perennial biogas crops influenced by harvest date. Industrial Crops and Products 58, 194–203. DOI: 10.1016/j.indcrop.2014.04.017 DOI
- Ruf, T.; Emmerling, C. (2018). Site-adapted production of bioenergy feedstocks on poorly drained cropland through the cultivation of perennial crops. A feasibility study on biomass yield and biochemical methane potential. Biomass and Bioenergy 119, 429–435. DOI: 10.1016/j.biombioe.2018.10.007 DOI
All sources of the site: bibliography.
Other substrates in the group “Energy crops and whole-crop plants (WCS)”
Sunflower, whole crop — BMP: 15 studies, weighted mean 287 m³ CH₄/t VS
287 m³ CH₄/t VS weighted mean from 15 studies
very good — editorial rating for biogas plants≈52 %
Beet roots (sugar/fodder beet) — BMP: 4 studies, weighted mean 397 m³ CH₄/t VS
397 m³ CH₄/t VS weighted mean from 4 studies
good — editorial rating for biogas plants≈52 %
Switchgrass — BMP: 3 studies, weighted mean 180 m³ CH₄/t VS
180 m³ CH₄/t VS weighted mean from 3 studies
≈52 %
Rapeseed, green biomass — BMP: 4 studies, weighted mean 367 m³ CH₄/t VS
367 m³ CH₄/t VS weighted mean from 4 studies
good — editorial rating for biogas plants66 %