BMP testingEnergy crops and whole-crop plants (WCS)

Wheat, whole crop — BMP: 13 studies, weighted mean 332 m³ CH₄/t VS

Wheat as a whole plant (GPS) is green forage or silage harvested before grain maturity. The records cover different harvest dates in an energy crop within a crop rotation.

rating: very good CH₄ 59 %

Published 4 June 2025Updated 29 October 20263 min readFeedstockData Editorial Team

Photo Vyacheslav Argenberg / Wikimedia Commons, licence CC BY 4.0, source file; changes: cropping

Weighted mean: 332m³ CH₄/t VS
Range: 228–418m³ CH₄/t VS
Records: 13studies
Publications: 2sources
Temperatures: 38 °C, 40 °Cof the test

Methane in biogas

59% CH₄

Medium methane content · ≈ 5.9 kWh/m³ of biogas

measured mean of 3 studies BMP, range 57.1–60.5 %; in a batch test the CH₄ share tends to be higher than in a plant.

How we calculate it and what the zones mean

Rating for biogas plants

very good — editorial rating for biogas plantsWorth accepting even for free or with a payment to the supplier

Potential per tonne of fresh matter: very high (123 m³ CH₄/t); no particular threats to stability. Handling costs: fibres, floating layer.

Why? Rating factors

Potential per tonne +3

+3potential 123 m³ CH₄/t fresh matter (BMP 332 × DM 37.7 % × VS 97.9 %)

Process stability 0

0no factors

Handling and costs −0.5

−0.5fibres, floating layer — shredding and intensive mixing

Total points: 2.5 · thresholds: ≥ 2.5 very good, ≥ 1 good, below — neutral; negative with cumulative process risk.

Editorial rating per the methodology · confidence of the rating: medium · excluding market prices

Add to the co-digestion calculator CSV data

BMP curves from 13 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 (332); 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.

Show the remaining records in the legend (1)

Records and sources

Download CSV

Source	BMP m³ CH₄/t VS	CH₄ in biogas % vol., measured	Temperature	Sample	Curve
Amon et al. (2007) · 1 DOI	228	—	38 °C · mesophilic	Wheat	end point (model curve)
Amon et al. (2007) · 2 DOI	229	—	38 °C · mesophilic	Wheat	end point (model curve)
Amon et al. (2007) · 3 DOI	243	—	38 °C · mesophilic	Wheat	end point (model curve)
Amon et al. (2007) · 4 DOI	244	—	38 °C · mesophilic	Wheat	end point (model curve)
Amon et al. (2007) · 5 DOI	245	—	38 °C · mesophilic	Wheat	end point (model curve)
Amon et al. (2007) · 6 DOI	251	—	38 °C · mesophilic	Wheat	end point (model curve)
Amon et al. (2007) · 7 DOI	254	—	38 °C · mesophilic	Wheat	end point (model curve)
Amon et al. (2007) · 8 DOI	307	—	38 °C · mesophilic	Wheat	end point (model curve)
Amon et al. (2007) · 9 DOI	342	—	38 °C · mesophilic	Wheat	end point (model curve)
Amon et al. (2007) · 10 DOI	343	—	38 °C · mesophilic	Wheat	end point (model curve)
Pouech (b.r.) · 1	384	59.4 %	40 °C · mesophilic	Wheat	end point (model curve)
Pouech (b.r.) · 2	387	60.5 %	40 °C · mesophilic	Wheat	end point (model curve)
Pouech (b.r.) · 3	418	57.1 %	40 °C · mesophilic	Wheat	end point (model curve)
Weighted mean	332	59.0 %	arithmetic mean 298, SD 68

Typical composition

Dry matter (DM): 37.7% (range 37.7–37.7)
Volatile solids (VS): 97.9 % DM (range 97.9–97.9)
Nitrogen: 2.4 % DM

Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: CROPGEN D4); dry matter: 1 determination, volatile solids: 1 determination. DM from a single determination – indicative value.

Sources: Pouech, P. Fruteau, H. Bewa, H.. Agricultural crops for….

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

seasonal
fibrous
editorial classification

Advantages

Methane potential in the database: weighted mean 332 m³ CH₄/t VS (median 254; range 228–418; 13 records from 2 sources).

Drawbacks and risks

Spread of results in the database: standard deviation 68 at a mean of 298 m³ CH₄/t VS (13 records from 2 sources).

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

Amon, T.; Amon, B.; Kryvoruchko, V.; Machmüller, A.; Hopfner-Sixt, K.; Bodiroza, V.; Hrbek, R.; Friedel, J.; Pötsch, E.; Wagentristl, H.; Schreiner, M.; Zollitsch, W. (2007) Methane production through anaerobic digestion of various energy crops grown in sustainable crop rotations. Bioresource Technology 98(17), 3204–3212
Weiland, P. (2010) Biogas production: current state and perspectives. Applied Microbiology and Biotechnology
Pouech, P. Fruteau, H. Bewa, H. (None) Agricultural crops for biogas production on anaerobic digestion plants. Biomass for energy and industry 163-165
Hendriks, A.T.W.M.; Zeeman, G. (2009) Pretreatments to enhance the digestibility of lignocellulosic biomass. Bioresource Technology
Herrmann, C. et al. (2011) Effects of ensiling, silage additives and storage period on methane formation of biogas crops. Bioresource Technology

The co-digestion calculator will assess a specific mixture containing this substrate.

What it is and where it comes from

The abbreviation GPS stands for whole-plant silage, that is, the whole plant harvested for ensiling. Wheat harvested in this way is cut and ensiled instead of being threshed for grain. The approach is considered as a complement to maize in a crop rotation, because harvest takes place earlier and a catch crop can be sown. The compilation contains records from several studies, including an experiment in which wheat was grown as an energy crop in a crop rotation and harvested at different dates, under mesophilic conditions.

Properties relevant to digestion

The composition changes with the developmental stage. At an early stage the plant has more protein and readily available compounds, at milk and wax ripeness the share of starch in the grain rises, and beyond that the share of woody straw increases. Harvest at the right stage gives a compromise between yield and digestibility. Ensiling cereals is usually easy, but too high a dry matter content makes compaction difficult. Unground grain reduces starch utilisation, so size reduction is important. Wheat has a lower C/N ratio than straw, so it is easier to combine with other substrates.

How to read the spread of results

The spread results mainly from the harvest date, which affects the proportion of starch to fibre, and from the variety, fertilisation and year. Some records come from a single series, so they are not independent. In the test, size reduction, inoculum, substrate-to-inoculum ratio and incubation length also have an effect. The data make it possible to assess the range of possible values, but do not replace a measurement for your own crop.

In biogas plant practice

Wheat GPS is attractive where maize is risky or where it is desired to spread harvest work over time. It is harvested with a forage harvester, ensiled in a silo and fed in a mix with other substrates. Rapid compaction and a tight cover are important to limit losses. Yield and cost-effectiveness depend on the soil class and conditions, so before planning crops it is worth comparing them with other plants. A BMP test stating the harvest stage helps to select the dose. It is good practice to record the cutting date and the developmental stage for each batch, because without this information the biogas production results from different years cannot be compared sensibly. A short analysis of the dry matter of the silage when it is taken out of the silo also helps.

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.

Full methodology and correction policy

Bibliography

All sources of the site: bibliography.