A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

COMPARISION THE SOIL RESPIRATION IN FOREST, PASTURE ANDAGROSILVIPASTORAL SYSTEM IN THE SOUTH AMAZONPaulo César Nunes 1 (Av. 04 de Julho n. 53, Centro – 78340-000 Juruena MT- Brazil;prnatura@terra.com.br)José Holanda Campelo Jr. 2 , Nicolau Priante Filho 2 ,Linda Akiko Yamamura 1 , Elke Leite Bezerra 31 . Instituto Pro Natura –IPN 2 Universidade Federal de Mato Grosso-UFMT3 Universidade de Varzea Grande -UNIVAGThe aim of this work was to compare the soil respiration of an area of primaryforest cover, with an extensive pasture system and an agrosilvopastoral system, inthe plane dystrophic dark Argissolo Red soil. We used an infrared gas analyzer(the Environment Gas Monitor, EGM-1/WMA-2: GAS ANALYSERS), attachedto a container able to retain 1170 cm 3 CO 2 . The experimental area is located in theExperimental Center of Agroforestry of the Instituto Pró Natura, in themunicipality of Juruena, Northwest Mato Grosso - Brazil. The treatmentsconsisted of three areas under different uses: an area of primary forest, a sevenyears old agrosilvipastoral system and a five years old extensive pasture system.The plots have 10m x 10 m, with 1 m measurement network executed betweenJanuary 2001 and February 2002. The results showed that in wet season during inthe morning, the soil respiration and soil temperature, measured at 1 cm depth,was significant different in three areas, with means 7.9 µmol CO 2 m -2 s -1 at 27.2ºCto pasture, 5.4 µmol CO 2 m -2 s -1 at 26.3 ºC to agrosilvipastoral system and 4.4µmol CO 2 m -2 s -1 at 24.8 ºC to jungle. In wet season in the afternoon the soiltemperature was significant different for the three places, but the soil respirationshowed significant differences only between forest with pasture and forest withagrosilvipastoral. The average during wet season in the afternoon ranged by 5.8µmol CO 2 m -2 s -1 at 30.8 ºC to the pasture, 5.38 µmol CO 2 m -2 s -1 at 28.5 ºC to theagrosilvipastoral system and 4,13 µmol CO 2 m -2 s -1 at 25.84 ºC to the forest.