Estoque de carbono em diferentes fisionomias de Caatinga do Seridó da Paraíba.

Abstract

Forests play a significant role in storing large amounts of Carbon in their biomass and other forest compartments, as in the understory, litter and soil. Thus, this study aimed to determine the amount of organic Carbon in an area of Caatinga different successional stages, in the compartments: understory, litter and soil in the rainy season and drought. The study was carried out at Cachoeira de São Porfírio, the city of Varzea – PB in 4 (four) areas de 3000 square meters each, with vegetation in different successional stages. Samples were collected from plant material in understory and litter, and soil samples to determine the levels of Carbon. The collect of understory and litter totaled 120 samples in each compartment. The plant material was sent to the laboratory of EMBRAPA Semi-Arido Petrolina-PE, to determine the organic carbon content. The soil was collected at 04 depths (0-5 cm, 5-10 cm, 10-15 cm and 15-20 cm), totaling 96 samples in the rainy season and dry season. Analyzes soil were performed at the Laboratory of Soil and Water / UFCG in Patos (PB). For comparison of the carbon content in each behavior was used, the significance level of 5%, and statistical analyzes carried out using the ASSISTAT statistical program. Were recorded in the rainy season, the highest values of carbon in the understory of Initial Secondary Caatinga, with 0.74 kg ha-1. In the dry season the highest carbon content was found in the Secondary Late Caatinga (0.68 kg ha-1). Litter in Caatinga Preserved had the highest average content of carbon and 2.42 kg ha-1 in the rainy season, in dry season, the area of Caatinga Late Secondary showed the highest carbon content (2.39 kg ha-1) and lowest value was obtained in the area of Caatinga Initial Secondary with 2.08 kg ha-1 carbon. The carbon content in the soil showed significant differences for time factors, the study area and depth. In the rainy season in the area of Caatinga Secondary Late was recorded the highest content of carbon in the soil with 9.00 Mg ha-1. In the dry season, the highest average content of carbon is in the area of Caatinga Preserved with 14.99 Mg ha-1. The Caatinga Late Secondary in the rainy season had the largest stock of carbon (33.01 Mg ha-1). In the dry season, the highest carbon stock was in the area of Caatinga Preserved with 49.77 Mg ha-1 carbon. The results of this study determined that the highest organic carbon contents were found in the area of Caatinga Preserved, and higher carbon concentrations were recorded during the dry season. Among the vegetable compartments, the highest concentration of carbon occurs in the litter. In soil, the highest concentration of carbon occurred in the surface layer (0-5 cm).