Resumo

TORRES VARGAS, Diana L.; QUIROZ GUERRA, Roberto  e  JUSCAMAITA MORALES, Juan. Effect of prescribed burning on microbial populations of grasslands soils of the Tupac Amaru SAIS - Junin, Peru. Ecol. apl. [online]. 2004, vol.3, n.1-2, pp.139-147. ISSN 1726-2216.

A study was carried out to evaluate the effects of prescribed burning (head fire) in populations of aerobic bacteria, anaerobic bacteria, fungi and two genus of Nitrogen-fixing bacteria (Azotobacter sp. and Azospirillum sp.) in Junín. Samples were taken from the end of the dry season (September 2001) to the beginning of the following dry season (June 2002). The burning experiment was carried out at the beginning of October (beginning of the rain season), using the Head Fire Burning methodology (it burns in favor of the wind). Characteristics of the soil, humidity, phosphorus, potassium, CEC, EC, cations, organic matter, nitrogen and pH, did not vary after the burning. Burning did not affect aerobic bacteria, anaerobic bacteria and fungi populations. Student’s t-test (α=0.05) was used and non significant differences were found between these populations before and after the burning. Regarding Nitrogen-fixing bacteria, great variations in the samples obtained immediately after burning were not observed. In the variance analysis, the No-Burning quadrat showed larger variances than the Burning quadrat. Application of fire in the Burning quadrat would have caused population stability, while the Nitrogen-fixing bacteria of the No-Burning quadrat showed greater spatial variability.

Palavras-chave : Prescribed burning; aerobic bacteria; anaerobic bacteria; fungi; Azotobacter; Azospirillum.

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