Dinâmica Da Acumulação De Fitomassa E Nutrientes Na Serapilheira Sob Plantios Clonais De Eucalipto

Abstract

O objetivo geral deste trabalho foi estimar a quantidade de fitomassa e nutrientes estocada na serapilheira acumulada e taxas de decomposição da serapilheira acumulada ao longo do ano em plantios com diferentes materiais genéticos de eucalipto, em áreas submetidas ou não ao desbaste florestal. O trabalho foi conduzido em Itatinga-SP. O experimento foi um delineamento de parcelas subdivididas. As parcelas foram compostas por 8 clones e um plantio semental, sendo subparcelas áreas em que foi realizado o desbaste e áreas sem desbaste. Para estimativa da serapilheira acumulada foram realizadas coletas em cada estação do ano, entre junho de 2015 e março de 2016. Após as avaliações concluiu-se que existiu um padrão de acúmulo de serapilheira associado às estações, com maiores valores na primavera e verão. A fração folhas foi a mais representativa quanto à quantidade de serapilheira acumulada no solo. Os valores de acúmulo total de serapilheira variaram pouco entre os materiais genéticos avaliados. A decomposição foi ligeiramente maior nas áreas desbastadas comparativamente às áreas sem desbaste. A sequência decrescente dos teores nas frações foi: Folhas > Galhos > Casca > Órgãos reprodutivos > Outros materiais. Quanto aos elementos a sequência foi: N > Ca > Mg > K > P.Palavras-chave: biogeoquímica florestal, serapilheira acumulada, desbaste, decomposição. DYNAMICS OF LITTER STOCK AND NUTRIENTS UNDER CLONAL EUCALYPTUS PLANTATIONS ABSTRACT: The objectives of this work were: to estimate the amount of phytomass and nutrients stored in the accumulated litter; to evaluate the seasonal variability of the amount of phytomass and nutrients in the accumulated litter and to estimate the decomposition rates of accumulated litter throughout the year. The work was conducted in Itatinga-SP. The experiment was an outline of subdivided plots. The plots were composed of 8 clones and one stallion planting, being subplots areas where thinning and non - roughing areas were performed. In order to estimate the accumulated litter, collections were made in each season of the year, between June 2015 and June 2016. After the evaluations it was concluded that there was a pattern of litter accumulation associated with the seasons, with higher values in spring and summer. The most representative leaf fraction was the amount of litter accumulated on the soil. Values of total litter accumulation were close between genetic materials. The decomposition was slightly higher in the thinned areas compared to the thinned areas. The decreasing sequence of the contents in the fractions was: Leaves> Branches> Bark> Other materials> Vegetable remains. As for the elements the sequence was: N> Ca> Mg> K> P.Keywords: forest biogeochemistry, litter stock, thinning, decomposition.

Biomass and carbón stocks in Eucalyptus spp. litterfall in an integrated production system

“…In addition to deposition, accumulation is also affected by mass loss through decomposition. It is known that the mass loss of E. urophylla is approximately 33% in one year, which makes it a good indication to accelerate the balanced cycle of nutrients (Vargas et al, 2019;Oliveira et al, 2020).…”

“…Usually, the leaves have the highest concentration of nutrients, as they are the metabolite center of the plant. However, the quantity and quality of nutrients supplied to the soil by litter deposition can vary, mainly with the forest stand species, and of the plant structures present in the litter (Vargas et al, 2019;Carvalho et al, 2019).…”