BMP testingWild, invasive and medicinal plantssingle study (5 samples)
Ipomoea fistulosa leaves — BMP: 5 studies, weighted mean 415 m³ CH₄/t VS
The leaves of bush morning glory (Ipomoea fistulosa, I. carnea) are the biomass of an invasive tropical shrub; they were studied in different size-reduction fractions, with a very consistent result.
rating: very goodCH₄ ≈ 52 % (estimate)
Photo Aris riyanto / Wikimedia Commons, licence CC BY-SA 4.0, source file; changes: cropping
- Weighted mean
- 415m³ CH₄/t VS
- Range
- 387–429m³ CH₄/t VS
- Records
- 5single study (5 samples)
- Publications
- 1source
- Temperatures
- 37 °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
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 (104 m³ CH₄/t); no particular threats to stability. No additional handling requirements.
Why? Rating factors
Potential per tonne +3
- +3potential 104 m³ CH₄/t fresh matter (BMP 415 × DM 28.5 % × VS 87.7 %)
Process stability 0
- 0no factors
Handling and costs 0
- 0no factors
Total points: 3 · 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 5 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 (415); 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 |
|---|---|---|---|---|
| Sharma et al. (1988) · 1 DOI | 387 | 37 °C · mesophilic | Ipomoea fistulosa · pretreatment: Material were first dried in the sun and then in an oven at 90oC | end point (model curve) |
| Sharma et al. (1988) · 2 DOI | 413 | 37 °C · mesophilic | Ipomoea fistulosa · pretreatment: Material were first dried in the sun and then in an oven at 90oC | end point (model curve) |
| Sharma et al. (1988) · 3 DOI | 421 | 37 °C · mesophilic | Ipomoea fistulosa · pretreatment: Material were first dried in the sun and then in an oven at 90oC | end point (model curve) |
| Sharma et al. (1988) · 4 DOI | 427 | 37 °C · mesophilic | Ipomoea fistulosa · pretreatment: Material were first dried in the sun and then in an oven at 90oC | end point (model curve) |
| Sharma et al. (1988) · 5 DOI | 429 | 37 °C · mesophilic | Ipomoea fistulosa · pretreatment: Material were first dried in the sun and then in an oven at 90oC | end point (model curve) |
| Weighted mean | 415 | arithmetic mean 415, SD 17 | ||
Typical composition
- Dry matter (DM)
- 28.5% (range 28.5–28.5)
- Volatile solids (VS)
- 87.7 % DM (range 87.7–87.7)
- C/N ratio
- 21.2
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: Sharma et al. (1988).
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
Low confidence: the description is based on general characteristics of the substrate group, not on studies of this material. Treat it as a hint to be verified.
Advantages
- Methane potential in the database: weighted mean 415 m³ CH₄/t VS (median 421; range 387-429; 5 records from 1 source).
Drawbacks and risks
- Spread of results in the database: standard deviation 17 at a mean of 415 m³ CH₄/t VS (5 records from 1 source).
Dosing
No dose data; because of the alkaloid content, only a small share, after a BMP test and monitoring of process stability.
Introduce gradually, starting with a small dose and monitoring the process (e.g. FOS/TAC, pH, gas composition).
Sources of the process data
The co-digestion calculator will assess a specific mixture containing this substrate.
What it is and where it comes from
Ipomoea fistulosa, also referred to as Ipomoea carnea, is a shrub of the morning glory family, native to South America and widely spread in the tropics, where it behaves as an invasive weed, for example along ditches and canals in India. The plant is toxic to animals and is therefore not used as feed. In the biogas literature it is considered as biomass whose harvesting is linked to limiting the range of the species.
Properties relevant to digestion
The leaves contain a lot of water, protein, soluble sugars and fibre, and the lignin is moderate. The plant contains alkaloids, including swainsonine, with a toxic effect on animals, but this is not a simple indicator of inhibition in the digester, and the effect on microorganisms is not well documented. Higher protein reduces the C/N ratio, so at large shares the risk of ammonia rises. Hydrolysis is rapid, and fresh mass spoils quickly.
How to read the spread of results
The dataset contains several records from a single study, under mesophilic conditions at 37 °C, with different size-reduction fractions of the leaves, and the results are very consistent. This means that within the range studied size reduction had little effect on the final result. It does not follow, however, that variability under other conditions would be small: the age of the leaves, the season, the place of harvest, sample preparation and the inoculum all have an effect.
In biogas plant practice
Bush morning glory leaves may be introduced into co-digestion with manure in regions where harvesting limits the spread of an invasive plant. The biomass must be size-reduced and used quickly or ensiled. Caution applies to the digestion residue if it were to be used as a fertiliser, because the composition of the secondary compounds is not precisely known. For installations in Poland the material is unavailable.
The situation is complicated by the fact that the plant produces large amounts of biomass, but harvesting it requires manual work and care because of its toxicity. Environmental advantages, such as limiting the invasion, must therefore be weighed against the costs of harvesting and the uncertainty regarding the properties of the digestate.
For completeness, the consistency of results in a test with different size reduction suggests high availability of the leaf components, but does not mean that shoots and woody parts of the plant behave in the same way. The result concerns the leaf fraction only.
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 = 0.134 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.
Bibliography
- Sharma, S.K.; Mishra, I.; Sharma, M.; Saini, J. (1988). Effect of particle size on biogas generation from biomass residues. Biomass 17(4), 251–263. DOI: 10.1016/0144-4565(88)90107-2 DOI
All sources of the site: bibliography.
Other substrates in the group “Wild, invasive and medicinal plants”
Common reed — BMP: 15 studies, weighted mean 170 m³ CH₄/t VS
170 m³ CH₄/t VS weighted mean from 15 studies
≈52 %
Para grass — BMP: 2 studies, weighted mean 240 m³ CH₄/t VS
240 m³ CH₄/t VS weighted mean from 2 studies
≈52 %
Rhubarb — BMP: 4 studies, weighted mean 368 m³ CH₄/t VS
368 m³ CH₄/t VS weighted mean from 4 studies
neutral — editorial rating for biogas plants67 %
Bermuda grass — BMP: 5 studies, weighted mean 202 m³ CH₄/t VS
202 m³ CH₄/t VS weighted mean from 5 studies
good — editorial rating for biogas plants≈52 %