Fig 1.
Geographic location of study sites in central-southern Brazil.
Fig 2.
Process diagram for the development of soil quality indexes tested in this study.
Fig 3.
Scree plot of principal component analysis.
Fig 4.
Examples of the scoring curve shapes used for scoring each soil quality indicator.
A) more-is-better function; B) less-is-better function; C) mid-point optimum function.
Table 1.
Indicator thresholds and scoring curves.
Table 2.
Soil functions framework and indicators§ used to develop the SQI-2.
Table 3.
Mean values of the 38 soil indicators (0–30 cm depth) in native vegetation (NV), pasture (PA) and sugarcane (SC) at three sites in central-southern Brazil.
Table 4.
Result of principal component analysis.
Fig 5.
Soil Quality Index (SQI)§ scores under native vegetation (NV), pasture (PA) and sugarcane (SC), for the 0–30 cm depth, at three sites in central-southern Brazil.
§SQI strategies: SQI-1: TDS/non-linear/simple additive, SQI-2: TDS/non-linear/weighted additive, SQI-3: MDS-PCA/non-linear/simple additive, SQI-4: MDS-PCA/non-linear/ weighted additive, SQI-5: MDS-EO /non-linear/simple additive, and SQI-6: MDS-EO /non-linear/weighted additive. *Mean values within each index followed by the same letter do not differ among themselves according to Tukey’s test (p<0.05).
Fig 6.
Overall Soil Quality Index (SQI) scores under native vegetation (NV), pasture (PA) and sugarcane (SC), for the 0–30 cm depth, in central-southern Brazil.
*Mean values within each index followed by the same letter do not differ among themselves according to Tukey’s test (p<0.05).
Fig 7.
Contribution of each soil functions in the SQI-2 under native vegetation, pasture and sugarcane in central-southern Brazil.
§Same letter within each soil function indicates that the mean values do not differ among land uses according to Tukey’s test (p<0.05).
Fig 8.
Contribution of each principal component (PC) and soil sector in the SQI-4 (A) and SQI-6 (B), respectively under native vegetation (NV), pasture (PA) and sugarcane (SC) in central-southern Brazil. §Same letter within each PC or soil sector indicates that the mean values do not differ among land uses according to Tukey’s test (p<0.05).
Fig 9.
Sensitivity values of SQ indexing strategies used to assess the land use change (native vegetation—pasture—sugarcane) impacts on soil quality in central-southern Brazil.
Fig 10.
Pearson’s correlation coefficients and probability of error (p) among soil quality indexes (SQI) developed to assess the land use change (native vegetation—pasture—sugarcane) impacts on soil quality in central-southern Brazil.