Effect of nitrogen and potassium fertilization on morpho-agronomic traits of three elephant grass (Pennisetum purpureum Schum.) genotypes for biomass production

Abstract

Elephant grass has been proposed for the energy sector as a possible source of renewable energy, because of its high biomass production. The aim of this study was to evaluate the effect of the mineral nutrients nitrogen and potassium on the morpho-agronomic traits (dry mater yield (DMY), percentage of DM (%DM), number of tillers per linear meter (NT), plant height (PH), stem diameter (SD) and leaf blade width (LW)) in different elephant grass genotypes in a randomized-block experimental treatment in a split-plot arrangement with three replications, in which the genotype factor (‘Cuban Pinda’ - G1; ‘IAC Campinas’ - G2; and ‘Cameroon’ - G3) was randomized in the plot, and the N and K factor was randomized in the sub-plot. The increase in nitrogen and potassium doses utilized influenced very little or almost did not influence the response of the three genotypes for the different morpho-agronomic traits assessed. The three genotypes had high number of tillers, height, and stem diameter at the lowest N and K doses, demonstrating a possible trend of high doses not providing a highly significant increase in these traits. The study of DMY showed that under a low nitrogen dose and with increase in potassium concentrations, dry matter yield increased; however, as the nitrogen dose increased in associated with potassium doses, dry matter yield did not augment, but was rather suppressed. The three elephant grass genotypes: ‘Cuban Pinda’, ‘IAC Campinas’, and ‘Cameroon’, had average dry yields of 52.66, 50.60, and 48.57 t ha^–1, respectively. Results are highly promising and prove the possibility of using elephant grass as an alternative source for biomass production.

Keywords: Renewable energy, mineral nutrients, production capacity