Resumo

BENINTENDE, Silvia Mercedes et al. Indicadores biológicos: selección, determinación de niveles de referencia y utilización en la construcción de índices. Cienc. suelo [online]. 2017, vol.35, n.1, pp.35-46. ISSN 1850-2067.

In this paper, our objectives were a) to test the utility of biological and biochemical variables to separate degraded areas from soils with minimal human disturbance of Mollisol and Vertisol soil orders and to select the most suitable ones to use as soil quality indicators; b) to generate information to establish reference levels of these variables, and c) to use them in the construction of an index to classify soils with different management history, according to their biological and biochemical quality. We took samples from Mollisol and Vertisol soils from Entre Ríos, corresponding to three soil subgroups. Samples were taken from areas with minimal human disturbance (PD), degraded areas (D), and areas with an intermediate degradation degree (I). Measured variables were: C and N in the microbial biomass (CBM and NBM), potential N mineralization (PMN-IA), organic carbon (Corg) and total N (Ntot). We analyzed the PD, D, and I zone separation by using discriminant analysis applied per soil order independently. Afterwards we built an index with four indicators selected with a prioritization matrix (CBM, PMN-IA, Corg and Ntot). We tested this index on soil samples whose quality we knew in advance. In Mollisols, the total misclassification rate was of 11.1%, while in Vertisols it was of 12.8%. We consider that these results show acceptable errors as the grouped soil series show a high variability. The PMN-IA was the most sensitive variable, reflecting the management effect on both soils. In degraded areas PMN-IA decreased by 60%, while CBM decreased between 30 and 35%. The biological quality index properly classified Aquic Argiudolls and a Typic Hapludert.

Palavras-chave : Soil health; Indicators selection; Biological health index.

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