Validação de cultivo e uso de variedades de capim-elefante para uso energético adaptadas ao bioma mata atlântica

Abstract

With the current perspective of depletion of reserves of energy sources of fossil origin, the use of biomass as an alternative input has been gaining importance in the development of alternatives for a sustainable energy matrix. The objective of this work is to conduct genotype interaction tests to validate the cultivation and use of elephant grass with potential for energy use from biomass recommended for the environmental conditions of the Northeast Coastal Tablelands (Atlantic Forest Biome) and to propose strategies of using cultivars for bioenergy production. The experiment was carried out at the Research and Development Execution Unit of Embrapa Tabuleiros Costeiros, in the municipality of Rio Largo/AL, where six elite genotypes of elephant grass were evaluated (Madeira, BRS Capiaçu, King Grass, Pasto Panamá, Cruzamento C6 and Crossing C8). The soil was classified as an Oxisol Yellow Cohesive Argissolic according to the Brazilian System of Soil Classification and as for its physical characteristics, the soil of the experimental area presented a sandy-clay texture The evaluations consisted of the analysis of biometric variables of growth (height, number of tillers) and in the determination of the biomass production of each of the varieties, four months after planting. The results show the highest tillering index of the Madeira (22.3 tillers m-1) and King Grass (24.9 tillers m-1) varieties. Plant height ranged from 3.8 m (C6 Cross) to 4.1 m (C8 Cross) but did not differ between varieties. The highest estimated annual productions of fresh biomass were registered in the Madeira (411.3 t ha-1 yr- 1) and King Grass (394.4 t ha-1 yr - 1) varieties. The highest dry biomass productions were registered in the Madeira (104.8 t ha- 1 yr 1) and King Grass (103.5 t ha- 1 yr 1) varieties. The average moisture content of the biomass ranged from 72.76% (BRS Capiaçu) to 76.97% (Pasto Panamá). The highest leaf/stem ratio was recorded in the BRS Capiaçu cultivar (0.72) and in the Capim C6 cross (0.63), while the other varieties showed a ratio of 0.54 (Pasto Panamá) to 0.59 (Madeira). The results demonstrate the technical viability and the great biomass production capacity of the elephant grass varieties in the Coastal Tablelands region (Atlantic Forest Biome), associated with rapid growth, perenniality and the possibility of performing multiple annual cuts. Keywords: Cenchrus purpureus (Schumach.) Morrone, lignocellulosic biomass production, productive performance.