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Data Brief
Data Brief
Data in Brief
2352-3409
Elsevier

S2352-3409(24)00806-0
10.1016/j.dib.2024.110842
110842
Data Article
Data on the effect of co-fermentation of maize and leguminous crops on biogas production, methane production and methane content in biogas
Kintl Antonín kintl@vupt.cz
a
Huňady Igor hunady@vupt.cz
a
Sobotková Julie sobotkova@vupt.cz
a
Vítěz Tomáš tomas.vitez@mendelu.cz
b
Brtnický Martin martin.brtnicky@mendelu.cz
c
Vejražka Karel vejrazka@vupt.cz
a
Elbl Jakub jakub.elbl@mendelu.cz
ad⁎
a Agricultural Research, Ltd., Zahradní 400/1, 66441 Troubsko, Czechia
b Department of Agricultural, Food and Environmental Engineering, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czechia
c Department of Agrochemistry, Soil Science, Microbiology and Plant Nutrition, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czechia
d Department of Agrosystems and Bioclimatology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czechia
⁎ Corresponding author. jakub.elbl@mendelu.cz
14 8 2024
10 2024
14 8 2024
56 1108422 6 2024
9 8 2024
9 8 2024
© 2024 The Author(s)
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).
The presented set of data brings results of the experimental production of biogas and methane from silages of alternative substrates consisting of maize and three leguminous species with a potential to make the production of biogas more friendly to the environment because the cultivation of legumes is generally considered to be more environment friendly than the cultivation of maize: white sweet clover (Melilotus albus Medik.), fodder vetch (Vicia villosa Roth.) and white lupin (Lupinus albus L.). Obtained data allow to compare the composition of experimental substrates and their important parameters (VS, DM, NDF, ADF, CF, starch, cellulose, hemicellulose, CP, lipids and ADL) as well as the yield of biogas, methane and methane in biogas from silage produced as a monosubstrate from the biomass of maize shreddings on the one side with silages produced from the mixture of biomass from maize and diverse legumes on the other side. This set of data can contribute to awareness about possibilities for reducing environmental risks connected with the cultivation of maize in growers of energy crops and operators of biogas plants. The reason is that a considerable number of farmers do not use new technologies of growing biomass for the production of biogas as they cannot quantify the potential impact on biogas yield and hence on the profitability of biogas plant operation. The measured values demonstrate that silages made from the mixed culture were reaching at least the same production of biogas and its quality as the monocultural maize silage.

Keywords

Biomass
Silage
Cropping system
Biogas
Methane yield
Legumes
Anaerobic digestion
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pmcSpecifications TableSubject	Environmental engineering	
Specific subject area	Anaerobic digestion, bioenergy, alternative plant substrates for biogas production	
Type of data	Raw data, Tables, Figures	
Data collection	Plant biomass for the production of silage was harvested manually at a stubble height of 18 cm and then processed into shreddings (15–20 mm) using the Deutz-Fahr MH 6505 cutter (Deutz-Fahr, Lauingen, Germany). The obtained shreddings were used to prepare model silages.
Model silages from alternative substrates were produced in mini-silos with using an inoculum (Silo Solve EF, Chr. Hansen Holding Ltd., Starovice, Czech Republic). After the incubation of 90 days, samples were collected from the mini-silos, which were homogenized, frozen and prepared for chemical analyses and fermentation tests.
Silage characteristics were determined according to Huňady et al. [1], Kintl et al. [2] and according to standards CSN EN 14346 [3], CSN EN 15934 [4], CSN EN 15169 [5] and ISO 13906 [6].
The fermentation tests were conducted in laboratory conditions in fermenters with the use of three systems and a total number of 24 batch fermenters in which anaerobic conditions were maintained. The analysis of the composition of produced biogas was made using the instrument Dräger X-am 8000 (Dräger, Germany).
The data were processed in the Statistica 14 programme (TIBCO Software, Inc., Palo Alto, SF, USA).	
Data source location	Research Institute for Fodder Crops, Ltd. Troubsko
664 41 Troubsko
Czech Republic
49.1730775 N, 16.5057914E	
Data accessibility	Repository name: Mendeley Data
Data identification number: DOI: 10.17632/jvcnmn2784.4
Direct URL to data: https://data.mendeley.com/datasets/jvcnmn2784/4
Instructions for accessing these data: data is open	

1 Value of the Data

• Taking into account the fact that cultivation of maize for biogas production brings certain environmental risks such as soil erosion, experiments were conducted with the cultivation of mixed crop of maize (Zea mays L.) and legumes.

• Compared the systems without legumes, the combination of maize and legumes is considered an alternative suitable for nitrogen savings, higher productivity per unit time and area.

• The presented data were obtained during the experimental production of biogas and methane from silages made of experimental substrates, which may reduce environmental risks connected with the growing of pure maize cultures.

• The presented data will allow research workers, growers and biogas plant operators to evaluate advantages of growing maize as monoculture and in mixed cultures of maize and various legume species in terms of silage production and production of biogas and methane in the process of anaerobic digestion.

2 Background

Demand for suitable alternative plant substrates is increasing with the growing number of biomethane plants. The currently dominating plant substrate is maize silage. However, intensive cultivation of maize (Zea mays L.) as an energy crop in pure cultures brings environmental risks such as soil erosion, depletion of the reserve of soil nutrients, low biodiversity or increased concentration of pests. This is why we focused our research on possibilities how to mitigate environmental risks connected with the monoculture maize cultivation as energy crop.

3 Data Description

The data contain classification of the quality of silage prepared in 4 variants based on the determination of the following parameters: dry matter content (DM), content of neutral detergent fibre (NDF), acido-detergent fibre (ADF), coarse fibre (CF), starch, cellulose, hemicellulose, proteins, lipids, acido-detergent lignin (ADL) and ash. One variant of silage was prepared only from the maize monosubstrate. The other variants were prepared by mixing the maize shreddings and specific legume in a weight ratio of 70:30 (Table 1).Table 1 Overview of individual silage substrates and their abbreviations. Percentage representation of maize and legumes in the substrate and its average density.

Table 1Silage	Acronym	Percentage of Maize in silage	Percentage of legumes in silage	Average density of silage in DM (kg/m3)	
Maize	MA	100	0	173.9	
Maize + White sweet clover	MA+WSC	70	30	166.6	
Maize + White lupin	MA+LU	70	30	150.2	
Maize + Fodder vetch	MA+VE	70	30	168.0	

3.1 Qualitative parameters of silage

Legend to Table 2: Mean of measured values (n = 3). All parameters were recalculated to sample dry weight (DM). MA – Maize, WSC – White sweet clover, LU – White lupin, VE – Fodder vetch. VS (volatile solids) NDF (Neutral Detergent Fibre), ADF (Acid Detergent Fibre), CF (Crude Fibre), CP (crude protein), ADL (Acid Detergent Lignin).Table 2 Mean contents of VS (%TS), NDF, ADF, CF, starch, cellulose, hemicellulose, CP, lipids and ADL (%DM) in the prepared silages.

Table 2VARIANT	VS (%TS)	NDF	ADF	CF	STARCH	ASH	CELLULOSE	HEMI-CELLULOSE	CP	LIPIDS	ADL	
MA	95.87	32.65	20.41	15.19	15.57	3.95	19.49	12.95	10.34	2.25	0.36	
MA+LU	95.00	33.25	22.42	15.91	34.99	4.25	23.42	11.04	12.31	3.38	0.60	
MA+VE	94.62	30.17	21.78	16.44	19.24	5.22	20.13	13.14	13.44	2.86	0.99	
MA+WSC	95.09	39.23	26.62	22.22	29.33	3.98	27.87	12.37	9.03	2.75	0.32	

3.2 Fermentation tests

Fig. 1 Dry matter (DM) content in the prepared silages. Mean of measured values (n = 3), ±SD Standard Deviation. MA = Maize, MA+LU = Maize+White Lupin, MA+VE = Maize+Vetch, MA+WSC = Maize+White Sweet Clover.

Fig. 1

Fig. 2 Biogas yield during 21 days of the experiment (average values for every day of measurement, n = 3 for one measurement, ± SD). MA = Maize, MA+LU = Maize+White Lupin, MA+VE = Maize+Vetch, MA+WSC = Maize+White Sweet Clover.

Fig. 2

Fig. 3 Methane yield during 21 days of the experiment (average values for every day of measurement, n = 3 for one measurement, ± SD). MA = Maize, MA+LU = Maize+White Lupin, MA+VE = Maize+Vetch, MA+WSC = Maize+White Sweet Clover.

Fig. 3

Fig. 4 Methane content in biogas during 21 days of the experiment (average values for every day of measurement, n = 3 for one measurement, ± SD). MA = Maize, MA+LU = Maize+White Lupin, MA+VE = Maize+Vetch, MA+WSC = Maize+White Sweet Clover.

Fig. 4

4 Experimental Design, Materials and Methods

4.1 Localization of the field experiment

Plant biomass intended for biogas production was cultivated in the Experimental station for Fodder Crops in Vatín. The station is located in the Czech-Moravian highland within the central part of the Czech Republic. The experimental station Vatín is 7 km south of Žďár nad Sázavou (Fig. 5). Mean altitude is 540 m a. s. l. The area of experimental station belongs to a slightly warm climatic zone. Plant biomass cultivation was carried out on the cambisol sandy loam, which is located on the deluvium of biotic orthogneiss. Basic information on characteristics of arable soil from experimental site is given in Table 3.Fig. 5 Area of our interest: an experimental site in the Czech Republic (Vatín).

Fig. 5

Table 3 Characteristics of arable soil from the experimental site (represented as mean ±SD; for n = 3) - average contents of plant available nutrients.

Table 3Sample	Soil reaction (pH)	Plant available nutrient content (mg kg-1)	
P	K	Ca	Mg	
Arable Soil	5.7 ± 0.21	98±7.7	246±27.8	1582±34.7	231±13.0	

4.2 Production of plant biomass – preparation of model silage

Stands of mixed crops and pure maize stands were established using precise seeding machine KINZE 3500 with the vacuum sawing system (Kinze Manufacturing, Williamsburg, IA, USA) “interplant system”. Seed hoppers of the sawing unit were filled with seeds so that distance between maize rows was 0.75 m. Legumes were sawn between the maize rows and the resulting spacing between individual rows of the mixed crop was 0.375 m (Fig. 6).Fig. 6 Field experiment organization: stand of mixed crop and scheme of biomass sampling (Kintl et al. [7]).

Fig. 6

Plant biomass was harvested manually at a stubble height of 18 cm and then processed into shreddings (15–20 mm) using the Deutz-Fahr MH 6505 cutter (Deutz-Fahr, Lauingen, Germany) [8]. The shreddings were used to prepare model silages – 4 variants of experimental silage, each in three repetitions.

One variant of the silage was prepared only from maize monosubstrates. The other variants were prepared by mixing the maize shreddings with a legume in the weight ratio of 70:30 (Table 2, Table 4).Table 4 Plants used in the mixed cropping system in 2018.

Table 4Tested plants	
White sweet clover	Melilotus albus Med.	
Fodder vetch	Vicia villosa Roth.	
White lupin	Lupinus albus L.	
Maize	Zea mays L.	

The process of preparing micro-silages was the same in all variants: 8 kg of shreddings were placed into a mini-silo (container with diameter of 150 mm and height 1 000 mm) together with inoculum (Silo Solve EF, Chr. Hansen Holding Ltd., Starovice, Czech Republic), dosed at 5 g + 3.5 l H2O/t. This inoculant contained the following bacteria: Lactococcus lactis, Lactobacillus plantarum, Enterococcus faecium. The final concentration of these microorganisms was 250 CFU x 103/g within fresh chop at the above dose (5 g + 3.5 l H2O/t). The prepared plant material was compacted with pneumatic press with a force of 6 000 N/m2. Then the mini-silos were hermetically closed and placed in dark at a temperature of 28±1 °C. Each container was equipped with a safety valve to remove surplus gaseous products. Silage compaction in the mini-silos ranged from 150.2 to 173.9 kgDM/m3 (Table 1).

After the incubation time of 90 days, the mini-silos were opened, samples collected from them were homogenized, then frozen and transported to the laboratory for chemical analyses and fermentation tests. Methods of producing model silages are described in detail in Kintl et al. [8] and Kintl et al. [9].

Fermentation tests were made in laboratory conditions according to the modified standard VDI 4630:2016. There were three systems with a total number of 24 batch fermenters used in the experiment. A simplified scheme of the laboratory system used for fermentation tests is presented in Fig. 7.Fig. 7 Scheme of the connection of laboratory batch fermenters (Kintl et al. [9]).

Fig. 7

A set of eight 5-litre glass fermenters was placed into each of 3 water baths where a temperature of 40 °C ± 0.2 °C was maintained by means of electric heating controlled by thermostat. The first day of the experiment, 3 kg of inoculum from an agricultural biogas plant were dosed into all fermenters (Table 5). Two fermenters in each of the systems were used as blind samples where endogenous production of the biogas of inoculum was measured. The remaining six fermenters were dosed silage samples with the aim to reach in all silages the resulting load with organic substances ca. 5 gVS/dm3 of the fermenter working volume. The substrate delay time in the fermenter was 21 days. Anaerobic conditions were maintained in the fermenters for the whole time of the experiment. Each fermenter was connected by hose with a glass measuring cylinder with a scale. The produced biogas pushed the salt-saturated solution from the glass cylinder into the expansion tank. The production of biogas was recorded from the measuring cylinder scale every day. Biogas accumulated in the glass cylinder could be analysed thanks to a sampling point with a quick coupler in each glass cylinder. The composition of produced biogas was analysed using the instrument Dräger X-am 8000 (Dräger, Germany). The resulting production of biogas was converted to normal conditions (p = 101,325 Pa; T = 273.15 K) and expressed in Nm3 per kg of added organic dry matter of the tested silage [2].Table 5 Characteristics of inoculum and test parameters of methane production.

Table 5Parameter	Legend	
Inoculum	
Place of collection	Biogas plant Čejč, Czech Republic; input material – maize silage and slurry; mesophilic temperature conditions (38 °C)	
Dry matter [%]	3.54 ± 0.07	
Annealing losses [%]	69.73 ± 0.11	
Test of methane production	
Fermenter volume	Total volume 5 dm3; workload 3 dm3	
Temperature [ °C]; heating mode	40 °C ± 0.2 °C; water bath	
Mixing	Manual, daily	
Delay time [day]	21	
Silage amount [g]	50 – 53	
Load with organic substances [gVS / Linoculum]	5 – 5.3	
Method of measuring biogas production	Method of liquid expansion according to standard VDI 4630	
Method of biogas composition measurement	Gas analyser Dräger X-am 8000; infrared sensors for CH4 and CO2, a mixture of gases used as a calibration gas (60% CH4 / 40% CO2)	
Number of repetitions	3 for each silage sample	

4.3 Statistical data processing

The data were processed in the Statistica 14 programme (TIBCO Software, Inc., Palo Alto, SF, USA).

Limitations

Not applicable.

Ethics Statement

The authors confirm to have been informed about ethical requirements for publication in the journal Data in Brief and follow them. They further confirm that this research does not include experiments on humans, animals or data obtained from the platforms of social media.

CRediT Author Statement

Antonín Kintl: Conceptualization, Methodology, Validation, Investigation, Resources, Data Curation, Writing - Original Draft, Supervision, Project administration, Funding acquisition. Igor Huňady: Methodology, Software, Validation, Formal analysis, Data Curation, Writing - Original Draft. Julie Sobotková: Formal analysis, Visualization. Tomáš Vítěz: Methodology, Investigation, Writing - Review & Editing, Supervision. Martin Brtnický: Formal analysis. Karel Vejražka: Formal analysis, Supervision. Jakub Elbl: Conceptualization, Formal analysis, Investigation, Writing - Original Draft, Writing - Review & Editing, Supervision.

Data Availability

DiB_DATASET_Data on the effect of co-fermentation_revised_version.xlsx (Original data) (Mendeley Data).

Acknowledgements

The result was obtained within the framework of institutional support MZE-RO1724.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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References

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