Análise da dinâmica da paisagem sob utilização de coivara em bioma de Mata Atlântica Estação Experimental de Pesquisa de Erosão em São Pedro da Serra – Nova Friburgo/RJ

Abstract

The use of fire in agriculture constitutes as an ancient practice, related to the first people of the Americas, transforming the landscapes that we are in. In southeastern Brazil, there is a mountainous regionof Nova Friburgo, State of Rio de Janeiro as a place that keeps the practice of using fire, known as slash and burn agriculture. The Coivara is performed infallow sites where vegetation is cut, the stumps of larger diameter are removed and others are put to dry and fired, causing flames with low intensity heat. This study aims to determine the changes in soil regarding the chemical, physical, hydraulic, hydrological and erosive properties. The study was developed in the São Pedro basin river in São Pedro da Serra, Nova Fiburgo/RJ. To realize the research it was assembled an Experimental Research Station Erosion (RISE), with three installments Erosion Wishmeyer type (88sqm) with separate systems: a) abandoned slash and burn and fallow 2-3 years system (PO), b) system without vegetation cover (SC) and c) Firing System – Coivara (CO). Disturbed and undisturbed samples were collected for chemical and physical analysis, hydraulic conductivity tests were performed by Guelph permeameter (IAC) and installed Blocks Granular Matrix (GMS) at depths of 20 cm and 40 cm to understand the hydrologic behavior in systems. In hydraulic conductivity tests, applying a load of 10 cm of water, the PO system presented in depth 7,13 x 10-3 e 1,06 x 10-2 in 15 cm and 30 cm respectively, the SC system showed 3,56 x 10-3 in 15 cm and 2,49 x 10-3 in 30 cm, and in the CO system, the value obtained was 5,34 x 10-3 in 15 cm and 1,78 x 10-3. In chemical analyzes, the data indicated a decrease in the value of Ca2+, Na+, Mg2+ e K+ as well as Organic Carbon values of the CO system compared to SC and. POsystems By monitoring done between January and August 2014, was obtained a total rainfall of. 05,75mm. The data of water and soil loss showed the greatest losses in the SC system (841,3l and 0,03531 ton/ha), the CO system showed water and soil losses of 811,1l and 0,01765 ton/ha and the PO system obtained the lowest losses, with 616,5l water and 0.01664 tons / ha of soil. In the hydrological behavior, the PO system showed the best drainages (3,40 to 20 cm and 40 cm 1,84) with optimal rates. Comparing the CO and SC systems in the depth of 20, cm, the behavior was very similarwith slight efficiency of SC (1,90) system at a depth of 40 cm, the CO system showed better drainage rates (0,28). The analysis of the data showed the PO system as the most efficient among the three systems studied. The fire, applied in the CO system management, although has changed some chemical properties, showed better results of the hydrological and erosive behavior when compared with the SC system.