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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Publications at this Location » Publication #324934
Title: Soil quality indexing strategies for evaluating sugarcane expansion in Brazil

Author
item CHERUBIN, MAURICIO - Universidad De Sao Paulo
item Karlen, Douglas
item CERRI, CARLOS - Universidad De Sao Paulo
item FRANCO, ANDRE - Colorado State University
item TORMENA, CASSIO - University Of Maringa
item DAVIES, CHRISTIAN - Shell Technology Center
item CERRI, CARLOS - Sao Paulo State University (UNESP)

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2016
Publication Date: 3/3/2016
Citation: Cherubin, M.R., Karlen, D.L., Cerri, C.E., Franco, A., Tormena, C.A., Davies, C.C., Cerri, C.C. 2016. Soil quality indexing strategies for evaluating sugarcane expansion in Brazil. PLoS One. https://doi.org/10.1371/journal.pone.0150860.

Interpretive Summary: We are not aware of any protocol for evaluating soil quality/soil health (SQ) changes induced by sugarcane expansion in Brazilian tropical soils. This field-study was conducted at three sites across of the largest sugarcane-producing region of Brazil to assess SQ changes due to land use change (LUC) which for this situation is defined as moving from native vegetation to pasture to sugarcane. This information will be useful to farmers, land managers, conservationists, and soil scientists in Brazil and elsewhere around the world.

Technical Abstract: Increasing demands for biofuels have intensified the land use change (LUC) for sugarcane cropping expansion in Brazil. Assessments of LUC-induced changes on soil quality (SQ) are essential for quantifying and monitoring the sustainability of sugarcane production over time. Since there is not a universal methodology to assess SQ, many attempts have been made worldwide for developing comprehensive SQ indexes (SQI) for specific purposes and ecosystems. We conducted a field-study in Brazil on three sites across the largest sugarcane-producing region for assessing SQ changes due to LUC (i.e., native vegetation through pasture to sugarcane) impacts using six SQ indexing strategies ranging from more complex to simpler approaches. Thirty eight soil indicators were included in the total dataset. Two minimum dataset were selected: one using principal component analysis (7 indicators) and the other, selected indicators based on expert opinion (5 indicators). Non-linear scoring curves were used to interpret the soil indicator values and simple additive and weighted additive approaches were used to integrate indicator scores into an overall SQI. Our findings indicated that simpler and more user-friendly SQI strategies were able to detect SQ changes as effectively as more complex SQI strategies. Therefore, a SQI strategy using a small number of carefully chosen soil indicators, such as: pH, P, K, VESS and SOC, and proportional weighting for indicator scores within each soil sector (chemical, physical and biological) could be used as a protocol for SQ assessments in Brazilian sugarcane areas. The LUC from native vegetation to extensive pasture significantly decreases overall SQ. In contrast, conversions from pasture to sugarcane had no significant impacts on overall SQ at the regional scale, although site-specific responses were found. Sugarcane production improves chemical attributes but decreases physical and biological attributes. The approaches used to evaluate SQ suggest that sugarcane expansion over degraded pastureland seems to be a sustainable strategy to meet increasing demands for biofuels. Nevertheless, management practices that alleviate negative impacts on soil physical and biological indicators must be prioritized within sugarcane production areas, thus preventing unintentional SQ degradation over time.