Soil quality index of an ultisol under long-term plots in the coastal tablelands in northeastern Brazil

Abstract

Soil quality, measured through its chemical, physical and microbiological attributes, changes as a result of anthropic sensations and becomes an important tool to assess environmental quality. The objective of this study was to determine and evaluate the Quality Index of an Ultisol in a long-term (17-yr) plots under different management systems in the Coastal Tablelands of Sergipe State, in Northeastern, Brazil. Main effects were conventional tillage (CT), no-tillage (NT), and minimum tillage (MT) distributed cultivated strips with corn as the main crop. Split-range treatments were randomly distributed and cultivated with cowpea beans (Vigna unguiculata), sunn hemp (Crotalaria juncea), pigeon pea (Cajanus cajan), and millet (Pennisetum glaucum). A forest soil was used as reference, compared to the soil samples of the cultivated area. The Soil Quality Index (SQI) for the 0-0.10 m layer was calculated by the additive method. There were changes in soil properties between the different management systems, and between the experimental soil and the reference area. The highest SQI was obtained from the forest area (67.1) followed by the NT treatment (65.5), MT (65.1) and CT treatment (61.0). The lowest SQI was observed in the CT treatment previously cultivated with pigeon pea (56.5). Among the evaluated soil functions, maintenance of homeostasis had the greatest influence on the SQI. The higher acidity of the forest soil helps to explain the origin of the limitations of the soil in the cultivated area that occupies the same type of soil, tolerated by the adoption of conservationist managements.

Corn Cropping Systems in Agricultural Soils from the Bajio Region of Guanajuato: Soil Quality Indexes (SQIs)

“…Compared with the present study, the use of PCA allows for a reduction in the number of indicators in an SQI, reducing its cost and complexity and thus facilitating its application in other areas with similar characteristics. In addition, the analysis of 10 soils with different characteristics considers environmental variability, which is the opposite of the study conducted by Assunção et al [58].…”

“…Assunção et al [58] developed an SQI based on a total data set composed of 24 physicochemical and biological indicators. They conducted their study on Ultisol soil in long-term plots (17 years) with different corn management systems in the Coastal Plateaus of Sergipe State, Northeast Brazil.…”

“…While the SMAF model used by Amorim et al [59] showed limitations in its sensitivity to differentiate soil quality in their long-term study, the PCA-based approach used by Hu et al [57] and the present study addresses this limitation by considering the specific conditions of the study area. Furthermore, the study by Assunção et al [58] highlights the importance of using a combination of physicochemical and biological indicators to improve the sensitivity of soil quality assessment. Compared with these studies, the present study adopted an integrated approach by using PCA and considering biological indicators.…”