Resumo

MARCELA, Toledo; DALURZO, Humberto  e  VAZQUEZ, Sara. Acid phosphatase in Oxisols under tobacco cropping. Cienc. suelo [online]. 2010, vol.28, n.1, pp.33-38. ISSN 1850-2067.

Soil biological parameters are of great value as sensitive indicators of transformations occurring under different uses and management practices (Mijangos et al., 2006). The aim of this study was to evaluate the activity of the acid phosphatase enzyme in Oxisols under tobacco cropping. The experimental design was in randomized complete blocks, with two treatments: subtropical rainforest (Sv) and tobacco cropping (Ta) (Nicotiana tabacum L.). Soil samples were taken from 0-10, 10 -20 and 20 -30 cm-deep layers. The variables measured were: APA, pH, clay content, total nitrogen (N), available phosphorus (P), respiration (RES), particulate organic matter (MOP) and soil organic carbon (CO). The soils used in the study showed an acid reaction. Organic carbon and N contents were higher in soils under the subtropical rainforest than under tobacco cropping. The highest APA was found under the subtropical rainforest and decreased in the three depths. In all treatments, APA was higher in the superficial layer; 70% of the APA variability was explained by N (p<0.0001). Forest elimination and the subsequent incorporation of soils to tobacco production lead to a reduction in the organic content of these soils and to a lower APA.

Palavras-chave : Enzymatic activity; Soil quality; Tobacco use.

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