Fernando de Oliveira Alari1, Nomaiaci de Andrade1, Abmael da Silva Cardoso2, Euclides Braga Malheiros1 and Ana Claudia Ruggieri3, (1)Department of Animal Science, FCAV, UNESP-Jaboticabal, Jaboticabal, Brazil (2)Department of Animal Sciences, Universidade Estadual Paulista - UNESP, Jaboticabal, SÃO PAULO, BRAZIL (3)Sao Paulo State University, Jaboticabal, Brazil
The emission of greenhouse gases by agricultural activity has been focused worldwide. In view of this, the knowledge about systems that mitigate these gases is of vital importance. The objective of this research is to evaluate the N2O flux by soil of massai grass pastures in silvipastural system kept under intermittent stocking by sheep. The experiment was conducted in forage science sector of FCAV, Jaboticabal UNESP, Brazil, from January to March 2013. The treatments consisted of two eucalyptus spacings (6.0 X 2.0m and 12.0 X 2.0m) subjected to grazing, a treeless treatment also subjected to grazing and a treeless treatment that has not been grazed. For entry the criteria used was 95% of light interception and for exit the parameter was 15 cm of canopy height. Three cycles were performed and after grazing the pickets were fertilized with 50 kg / ha of nitrogen, being that only the treatment that had not been grazed received no fertilizer. N2O flux, temperature and soil moisture were evaluated after the removal of the animals from pickets for 10 days. The average cumulative emission of the three grazing cycles in 10-day evaluation of N2O was 1476.1 (± 730.7), 2682.6 (± 1642.3) and 2156.648 (± 1077.4) μgN-N2O for the grazed treatments with spacing of 6 and 12 m, and the treatment without trees, respectively. For the treatment without trees and ungrazed was observed a cumulative N2O consumption of 622.6 (± 572.4) μgN-N2O. In the third grazing cycle the N2O emission increased by 80, 77 and 74% in relation to the other cycles in grazed treatments spacing 6 and 12 m and treeless. In the treatment without trees and without grazing the consumption of N2O increased by 65% in the third cycle. The introduction of animals in the silvipastural system alter the flux of N2O.