TY - JOUR

T1 - Vinasse application and cessation of burning in sugarcane management can have positive impact on soil carbon stocks

AU - Zani, C.F.

AU - Barneze, A.S.

AU - Robertson, A.D.

AU - Keith, A.M.

AU - Cerri, C.E.P.

AU - McNamara, N.P.

AU - Cerri, C.C.

PY - 2018/8/7

Y1 - 2018/8/7

N2 - Bioenergy crops, such as sugarcane, have the potential to mitigate greenhouse gas emissions through fossil fuel substitution. However, increased sugarcane propagation and recent management changes have raised concerns that these practices may deplete soil carbon (C) stocks, thereby limiting the net greenhouse gas benefit. In this study, we use both a measured and modelled approach to evaluate the impacts of two common sugarcane management practices on soil C sequestration potential in Brazil. We explore how transitions from conventional (mineral fertiliser/burning) to improved (vinasse application/unburned) practices influence soil C stocks in total and in physically fractionated soil down to one metre. Results suggest that vinasse application leads to an accumulation of soil C of 0.55 Mg ha-1 yr-1 at 0-30 cm depth and applying unburned management led to gains of~0.7 Mg ha-1 yr-1 at 30-60 cm depth. Soil C concentration in the Silt+Clay fraction of topsoil (0-20 cm) showed higher C content in unburned management but it did not differ under vinasse application. The CENTURY model was used to simulate the consequences of management changes beyond the temporal extent of the measurements. Simulations indicated that vinasse was not the key factor driving increases in soil C stocks but its application may be the most readily available practice to prevent the soil C losses under burned management. Furthermore, cessation of burning may increase topsoil C by 40% after ~50 years. These are the first data comparing different sugarcane management transitions within a single area. Our findings indicate that both vinasse application and the cessation of burning can play an important role in reducing the time required for sugarcane ethanol production to reach a net C benefit (payback time). © 2018 Zani et al.

AB - Bioenergy crops, such as sugarcane, have the potential to mitigate greenhouse gas emissions through fossil fuel substitution. However, increased sugarcane propagation and recent management changes have raised concerns that these practices may deplete soil carbon (C) stocks, thereby limiting the net greenhouse gas benefit. In this study, we use both a measured and modelled approach to evaluate the impacts of two common sugarcane management practices on soil C sequestration potential in Brazil. We explore how transitions from conventional (mineral fertiliser/burning) to improved (vinasse application/unburned) practices influence soil C stocks in total and in physically fractionated soil down to one metre. Results suggest that vinasse application leads to an accumulation of soil C of 0.55 Mg ha-1 yr-1 at 0-30 cm depth and applying unburned management led to gains of~0.7 Mg ha-1 yr-1 at 30-60 cm depth. Soil C concentration in the Silt+Clay fraction of topsoil (0-20 cm) showed higher C content in unburned management but it did not differ under vinasse application. The CENTURY model was used to simulate the consequences of management changes beyond the temporal extent of the measurements. Simulations indicated that vinasse was not the key factor driving increases in soil C stocks but its application may be the most readily available practice to prevent the soil C losses under burned management. Furthermore, cessation of burning may increase topsoil C by 40% after ~50 years. These are the first data comparing different sugarcane management transitions within a single area. Our findings indicate that both vinasse application and the cessation of burning can play an important role in reducing the time required for sugarcane ethanol production to reach a net C benefit (payback time). © 2018 Zani et al.

KW - Bioenergy crop

KW - CENTURY model

KW - Management practice changes

KW - Payback time

KW - Physical fractionation

KW - Soil carbon profile

KW - carbon

KW - fertilizer

KW - phosphorus

KW - potassium

KW - trace element

KW - agricultural management

KW - alcohol production

KW - Article

KW - bulk density

KW - combustion

KW - comparative study

KW - flotation

KW - macronutrient

KW - nonhuman

KW - precipitation

KW - sedimentation

KW - soil analysis

KW - soil moisture

KW - soil texture

KW - sugarcane

KW - temperature

KW - vinasse

U2 - 10.7717/peerj.5398

DO - 10.7717/peerj.5398

M3 - Journal article

VL - 6

JO - Peerj

JF - Peerj

SN - 2167-8359

IS - 8

M1 - e5398

ER -