Phosphorus Fertilization and Harvest Intervals Influence Energetic and Physical Properties of Briquettes and Large Branches of Mate

Abstract

-In mate crop, the commercial part consists of leaves and thin branches, while the large branches (LB) are considered unused residues and left in the field, although they may have potential for use as energy. The objective of this paper was to evaluate the influence of phosphorus fertilization and harvest interval in productivity of mate large branches and in their physical and energetic properties, as well as in derived briquettes. In a seven-year-old plantation, doses of 0, 20, 40, 80, 160 and 320 kg.ha -1 of P 2 O 5 were applied considering harvest intervals of 12, 18 and 24 months. Dry mass, average diameter, P content, and physical and energetic properties of LB were determined. With LB, after its transformation into particles and briquetting, physical and energetic properties were determined, as well as P availability in soil. The phosphorus fertilization increased LB productivity in larger harvest intervals, increasing the amount of energy produced per unit of area, but did not change basic density and gross calorific value of wood. Mate harvest intervals did not affect the apparent density and calorific value of briquettes produced by LB. LB harvested at intervals of 18 and 24 months produced wood with higher basic density and gross calorific value. LB or briquettes have adequate energetic and physical properties, being technically a plant residue with great potential for use as energy.Keywords: Plant residues; Renewable energy; Ilex paraguariensis. ADUBAÇÃO FOSFATADA E INTERVALOS DE COLHEITA INFLUENCIAM AS PROPRIEDADES ENERGÉTICAS E FÍSICAS DE BRIQUETES E DE GALHOS GROSSOS DE ERVA-MATERESUMO -Na colheita da erva-mate, a parte comercial é composta por folhas e galhos finos, enquanto os galhos grossos (GG) são considerados resíduos e deixados no campo, mas que podem apresentar potencial para uso como energia. O objetivo do trabalho foi avaliar a influência da adubação fosfatada e do intervalo de colheita na produtividade de galhos grossos de erva-mate e em suas propriedades físicas e energéticas e, de briquetes deles derivados. Em um erval com sete anos aplicaram-se doses de 0, 20, 40, 80, 160 e 320 kg.ha -1 de P 2 O 5 e utilizandos os intervalos de colheitas de 12, 18 e 24 meses. Determinou-se a massa seca, diâmetro médio, teor de P e propriedades físicas e energéticas dos GG. Com os GG, após sua transformação em partículas e briquetagem, foram determinadas propriedades físicas e energéticas. Determinou-se, ainda, a disponibilidade de P no solo. A adubação fosfatada aumentou a produtividade do GG em intervalos maiores de colheita, aumentando a quantidade de energia produzida por unidade de área, mas não alterou a densidade básica e poder calorífico superior da madeira. Os intervalos de colheita da erva-mate não interferiram na densidade aparente e no poder calorífico de briquetes produzidos pelo GG. Os GG colhidos com intervalos de 18 e 24 meses produziram madeira com maior densidade básica e poder calorífico superior. Os GG ou os briquetes apresentam propriedades energéticas e físicas adequadas...

Energy properties of bamboo biomass and mate co-products

“…Moreira (2012) [38] found ash content increasing with age, due to the accumulation of siliceous bodies. Santin et al [29] in a study with mate branches found mean ash content close to 3.9%. High ash content contributes to the reduction of biomass HCV, considering that it is a mineral content not activated in the combustion process [39].…”

“…Vittata 0.462 g cm − 3 , while for Dendrocalamus asper, the values were 0.604 g cm − 3 . Santin et al [29] found mean values close to 0.400 g cm − 3 for basic density of mate pruning branches aged 12-36 months. Carvalho et al [14] observed a density of approximately 0.400 g cm − 3 of mate branches.…”

“…DEB values observed in this study corroborate the results found in the literature. Santin et al [29] in a study with mate pruning branches found DEB of 7.57 GJ m − 3 . Santos et al [18] in a study with bamboo species and wood of the Eucalyptus grandis × Eucalyptus urophylla hybrid found an average DEB value of 9.68 GJ m − 3 and 9.80 GJ m − 3 , respectively.…”

“…GCV average value corroborates the results found in the literature. Rambo et al [11], Guarnetti and Coelho [12], Vale et al [25] and Brito et al [26] [29].…”