Elephant grass ecotypes for bioenergy production via direct combustion of biomass
Introduction
Plant biomass for energetic feedstock has gained importance in the development of alternative energy for an environmentally renewable and sustainable energy matrix (Nass et al., 2007, Samson et al., 2005), since it can be converted into chemical products, thermal/electrical energy, biofuels, among other essential materials (Fontoura et al., 2015, McKendry, 2002).
The biomass of crops intended to be used for combustion should have low proportion reproductive structures in the biomass, as well as phenology that allows long growing season, associated with high biomass production (Porter et al., 2007). Aside from morpho-agronomic traits, some authors indicate that biomass quality properties (moisture content, calorific value, ash content, and cellulose, lignin, and nitrogen levels) are fundamental for its utilization, since they are able to influence the entire conversion process and thermal utilization (Dorez et al., 2014, Gani and Naruse, 2007, Jaradat, 2010, Karp and Shield, 2008, McKendry, 2002, Obernberger et al., 2006, Prochnow et al., 2009).
Several crops have been quoted as candidates for biomass energy generation (Boehmel et al., 2008, David and Ragauskas, 2010, Ra et al., 2012, Sanderson and Adler, 2008). Some authors (Fontoura et al., 2015, Morais et al., 2009, Ra et al., 2012, Strezov et al., 2008) have highlighted elephant grass (Pennisetum purpureum Schum.), mainly for gathering appropriate biomass quality traits and high biomass production.
However, the quantification of the biomass quality is costly and time-consuming. Thus, selection based on morpho-agronomic traits in order to obtain indirect gains in biomass quality is a promising strategy at the initial stages of an elephant grass breeding program for bioenergy. In this sense, the canonical correlation analysis is noteworthy, since it maximizes the estimate of the correlation between two sets of variables (Rajasundaram et al., 2014).
Furthermore, the understanding of the association between calorific value released by biomass combustion and its main morpho-agronomic and biomass quality traits contribute for the selection of genotypes with greater calorific value and biomass production. However, according to Silveira et al. (2015), the simple correlation among traits does not represent the cause-effect measurement, and its direct interpretation may result in mistakes in the selection strategy. In this context, the path analysis is noteworthy since it decomposes the simple correlation coefficient into direct effects and indirect effects in relation to a variable of interest (Tyagi and Lal, 2007).
Morphological variability in elephant grass germplasm can be divided into four groups of standard ecotypes: Cameroon – presents erect genotypes with thick stalks, broad leaves, upright clumps and late flowering; Napier – presents genotypes with thick/intermediate stalks, broad leaves, open clumps and intermediate flowering; Mecker – presents reduced height genotypes with thin stalks, thin and more numerous leaves, and early flowering; and Dwarf – presents lower height genotypes (up to 1.5 m high), and high leaf/stalk ratio (Lira et al., 2010). However, there were no reports on the interrelations between biomass quality and morpho-agronomic traits in these groups, which could determine their potential in the production of bioenergy via direct combustion.
Thus, the objective of this study was to evaluate the aptitude of the groups Cameroon and Napier, aiming at the breeding of elephant grass for the bioenergy production via direct combustion.
Section snippets
Genetic material and experimental conduction
A total of 100 accessions of the Active Elephant Grass Germplasm Bank of Embrapa (BAGCE) were used, of which 18 were classified in the Cameroon group, 44 in the Napier group, four in the Mercker group, and the other accessions were classified as intermediate to the aforementioned groups. However, only the data of the groups Cameroon and Napier were used to compare the aptitude, due to the small number of genotypes in the Mercker group, and to the non-existence of genotypes of the dwarf group in
Napier vs. Cameroon comparison
Table 1, Table 2 show the genotypic values of the morpho-agronomic and biomass quality traits of the groups Napier (44 accessions) and Cameroon (18 accessions). There was significant variability for all of the morpho-agronomic traits for both the Napier and Cameroon groups. The same was observed for biomass quality traits, except for HCEL, which did not present variability in either of the groups.
Considering the F test to contrast the treatment effect – Napier vs. Cameroon – for the 17 traits
Conclusions
In general, the present results suggest that the Cameroon group presents the greatest aptitude when compared with the Napier group for the generation of bioenergy from biomass combustion. The ASH level is highly correlated with and has direct effect on CAV. Genetic breeding from the morpho-agronomic traits within the Cameroon group is recommended; therefore, among the genotypes with higher total dry biomass, it should be selected those with greater height and stalk diameter, in order to obtain
Conflict of interest
The authors declare no conflict of interest.
Acknowledgments
The authors thank the agencies CAPES, FAPEMIG and UNIPASTO for the financial support to this research.
References (36)
- et al.
Comparing annual and perennial energy cropping systems with different management intensities
Agric. Syst.
(2008) - et al.
Effect of cellulose, hemicellulose and lignin contents on pyrolysis and combustion of natural fibers
J. Anal. Appl. Pyrol.
(2014) - et al.
Elephant grass biorefineries: towards a cleaner Brazilian energy matrix?
J. Clean. Prod.
(2015) - et al.
Effect of cellulose and lignin content on pyrolysis and combustion characteristics for several types of biomass
Renew. Energy
(2007) Energy production from biomass (part 1): overview of biomass
Bioresour. Technol.
(2002)- et al.
An evaluation of South African fuelwood with regards to calorific value and environmental impact
Biomass Bioenergy
(2009) - et al.
Chemical properties of solid biofuels − significance and impact
Biomass Bioenergy
(2006) - et al.
Bioenergy from permanent grassland – a review: 2
Combust. Bioresour. Technol.
(2009) - et al.
Biomass yield and nitrogen use efficiency of cellulosic energy crops for ethanol production
Biomass Bioenergy
(2012) - et al.
Thermal conversion of elephant grass (Pennisetum Purpureum Schum) to bio-gas, bio-oil and charcoal
Bioresour. Technol.
(2008)
Association of Official Analytical Chemical. Official Methods of Analysis of the Association of Analytical Chemists
GENES – a software package for analysis in experimental statistics and quantitative genetics
Acta Sci. Agron.
Switchgrass as an energy crop for biofuel production: a review of its ligno-cellulosic chemical properties
Energy Environ. Sci.
Forage fiber analysis: apparatus, reagents, procedures and some applications
Agric. Handbook Washington, D.C
Best linear unbiased estimation and prediction under a selection model
Biometrics
Genetic resources of energy crops: biological systems to combat climate change
Aust. J. Crop Sci.
Bioenergy from plants and the sustainable yield challenge
New Phytol.
Melhoramento genético do capim-elefante
Cited by (31)
Bioenergy elephant grass genotype selection leveraged by spatial modeling of conventional and high-throughput phenotyping data
2022, Journal of Cleaner ProductionCitation Excerpt :These samples were dried using a kiln at 56 °C until a constant weight was achieved, and then the dry matter (DM, in %) was calculated. Total dry biomass (TDB) (Mg ha−1 year−1) was quantified as described by Rocha et al. (2017). The experimental area was surveyed using a DJI Inspire 1 Pro quadcopter coupled with DJI Zenmuse X5 optical sensors (DJI technology Co., Shenzhen, China) and a Sentera Multispectral Double 4k (Sentera Inc., St Paul, MN, USA).
Integrated analyses of phenotype, phytohormone, and transcriptome to elucidate the mechanism governing internode elongation in two contrasting elephant grass (Cenchrus purpureus) cultivars
2021, Industrial Crops and ProductsCitation Excerpt :Elephant grass, otherwise known as Napier grass, is a perennial herb native to the tropical grasslands of Africa. Elephant grass is utilized to biofuel production and useful raw material for papermaking due to its ease of establishment, rapid propagation and fast regrowth capacity; thus, this valuable crop is grown in tropical and subtropical regions around the world (Chen et al., 2016; Neves et al., 2018; Rocha et al., 2017). Internode elongation is one of the most important traits in elephant grass because of its relation to plant height and biomass productivity.
Optimal harvest number and genotypic evaluation of total dry biomass, stability, and adaptability of elephant grass clones for bioenergy purposes
2021, Biomass and BioenergyCitation Excerpt :These samples were dried in a kiln at 56 °C until constant weight, and then the dry matter concentration (%) was calculated. The total dry biomass was quantified as described by Rocha et al. [7]. The genotypic stability of the clones was assessed using the harmonic mean of the genotypic values (HMGV), a method for ranking genotypes that simultaneously considers their total dry biomass and stability over harvests [32].
Potential of Napier grass (Pennisetum purpureum Schumach.) for phytoremediation and biofuel production
2020, Phytoremediation Potential of Perennial GrassesInvestigation of pyrolysis kinetics and thermal behavior of Invasive Reed Canary (Phalaris arundinacea)for bioenergy potential
2019, Journal of Analytical and Applied PyrolysisCitation Excerpt :Moreover, second stage was subdivided into two zones as two peaks were a raised there. The typical trend of TG curves were also observed at different temperature ranges when compared to Date palm [41], duck weed [42], Napier grass [43], elephant grass [44], corn cob, corn stover [45], cattle manure and rice straw [46,47]. The mass loss of RC associated with the pyrolysis temperature was explained in Tables 3 and 4 .
Elephant grass leaves have lower recalcitrance to acid pretreatment than stems, with higher potential for ethanol production
2018, Industrial Crops and Products