Soil physical quality response to sugarcane expansion in Brazil

Authors: CHERUBIN, MAURICIO - Universidad De Sao Paulo; Karlen, Douglas; FRANCO, ANDRE - Colorado State University; TORMENA, CASSIO - University Of Maringa; CERRI, CARLOS - Universidad De Sao Paulo; DAVIES, CHRISTIAN - Shell International Exploration & Production, Inc; CERRI, CARLOS - Universidad De Sao Paulo

Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/2/2016
Publication Date: 1/10/2016
Publication URL: http://handle.nal.usda.gov/10113/6056847
Citation: Cherubin, M.R., Karlen, D.L., Franco, A.L.C., Tormena, C.A., Cerri, C.E.P., Davies, C.A., Cerri, C.C. 2016. Soil physical quality response to sugarcane expansion in Brazil. Geoderma. 267:156-168. https://doi.org/10.1016/j.geoderma.2016.01.004.

Interpretive Summary: The land area devoted to sugarcane production in Brazil is increasing rapidly to meet increasing global demand for biofuel. The typical land use change (LUC) to support this increase is to convert native vegetation to pasture and then to sugarcane production. This study measured changes in soil physical properties in response to this LUC. We conclude that to be sure soil quality/health is not decreased, the change in land use should be managed in ways that increase the soil organic matter and minimize soil compaction. This information will be useful to farmers, land managers, conservationists, and soil scientists in Brazil and elsewhere around the world.

Technical Abstract: With an increasing global demand for bioenergy, the rate of land-use change (LUC) is increasing rapidly to support cellulosic feedstock production. In Brazil, sugarcane (Saccharum officinarum) expansion to produce ethanol is displacing degraded pastures, but long-term effects of this LUC are unknown. This study was conducted at three sites in the central-southern region of Brazil to quantify the impacts of a typical LUC sequence (i.e., native vegetation – pasture – sugarcane) on soil physical quality. On-farm and laboratory soil analyses were performed and soil physical properties were evaluated separately and also a minimum dataset was defined to assess the soil physical quality using an additive index (SPQI). Conversion from native ecosystems to pasture increased soil compaction and decreased the soil’s ability to supply water and oxygen to plants. Based on our SPQI the soil’s capacity to perform its physical functions decreased from 90% in native vegetation to 73% in pasture. Land use change from pasture to sugarcane induced slight soil physical quality degradation, resulting in soils functioning between 69 and 56% of their capacity. Overall, sugarcane fields have lost soil physical quality identified by decreasing soil porous space, soil aeration and water hydraulic conductivity (Kfs) and increasing soil strength, structural degradation and erosion risks. Tillage operations performed during the sugarcane replanting (each ~5 years after the planting of sugarcane) had a short-term positive effects on soil physical quality, although over time it further reduced the soil’s ability to resist to erosion and structural degradation. We conclude that for sustainable sugarcane expansion in Brazil under degraded pasture, these areas should be managed in ways that increase the soil organic matter and minimize soil compaction. These actions are needed to prevent further soil physical quality degradation and to improve both economic and environmental sustainability of sugarcane ethanol production.