Biomassa e carbono em plantios de Schizolobium parahyba var. amazonicum sob diferentes espaçamentos em área de pastagem

• Autor(a) principal: Delarmelina, William Macedo
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/11063
• topic: Soil carbon; Isotopic carbon; Planting spacing; Carbono no solo; Carbono isotópico; Espaçamento de plantio; Recursos Florestais e Engenharia Florestal; 630

Carbon in forest plantations is extremely relevant in environmental and silvicultural issues. The conversion of pastures to forest plantations is among the main strategies to reduce soil carbon losses. Under the hypothesis that higher planting densities influence soil organic carbon, an experiment with Schizolobium parayba var. amazonicum plant in an established pasture area was studied in order to quantify the biomass and carbon stock under different spacing, as well as to evaluate the effect of the trees on the organic carbon of the soil. The experiment is located in IFES-Campus Alegre - ES. Five planting spacings were studied: 3 m x 2 m, 3 m x 3 m, 4 m x 3 m, 4 m x 4 m and 5 m x 5 m, in a randomized complete block design with three replications. The forest inventory of the stand was taken to obtain the dendrometric variables. The biomass and the carbon content were obtained by means of the direct method, contemplating all the compartments of the tree above the ground and root. The organic carbon was determined in the soil, considering the depths 0-5 cm, 5-10 cm, 10-20 cm and 0-20 cm. The C contents and the stable isotope values of carbon (d13C) were obtained by means of the mass spectrometer. Soil density was determined by the volumetric ring method. Values of d13C in soil and senescent leaves of grasses and S. parayba var. amazonicum were used to calculate the proportion of soil carbon derived from grass. It was verified that in the larger spacings (4 m x 4 m and 5 m x 5 m), the plants had the highest average diameters, being 14.29 cm and 14.19 cm, respectively. The inverse was found for height, where the spacing 3 m x 2 m provided the highest mean (13.35 m). The highest levels of carbon in the biomass were found in the bark, branches and leaves, and the lowest content in the stem. The different planting spacings did not influence the carbon content in the wood, however due to the higher planting density, the smaller spacings were responsible for the higher values of biomass and carbon stock above and below the soil for settlement. The study highlights the rapid change in soil carbon origin after the conversion of pasture established for forest plantations with part of the COS originating from the plantations of S. parayba var. amazonicum.