Bioenergy is an important and feasible option for mitigating global warming and climate change. However, large-scale land-use change (LUC) to expand bioenergy crops, such as sugarcane, raises concerns about the potential negative environmental and socioeconomic side effects. Such effects are context-specific, and depending on the LUC scenario and management practices, several co-benefits can be attained. We reviewed the literature and discussed how LUC and best management practices affect key components of sustainability (e.g., soil health, soil carbon (C) sequestration, greenhouse gas emissions (GHG) emissions, nutrient cycling, water quality, among others) of sugarcane-derived bioenergy production in Brazil. Sugarcane expansion has occurred predominantly over pasture areas, although converting croplands could be also an environmentally feasible option. The land transition from low-productivity pastures to sugarcane cultivation seems to be a sustainable pathway to increase bioenergy production. This LUC scenario enhances soil health and soil C sequestration over time, although soil compaction, biodiversity loss, and erosion are still challenging. Besides, adopting best management practices, such as conservation tillage, sustainable crop residue management, rational fertilization, and recycling by-products, has been fundamental to ensuring sustainable bioenergy production. Public policies and well-designed legal frameworks and regulations, such as the Forest Code and the RenovaBio legislations in Brazil, are necessary to make bioenergy production compatible with rational land use and protection. Lastly, our analysis provided insights into sugarcane expansion over a small proportion (1%) of pasture areas in Latin American and Caribbean (LAC) and sub-Saharan African (SSA) countries, which may result in a substantial impact on global bioenergy supply. We concluded that sugarcane-derived bioenergy is a sustainable option to tackle climate change while provisioning other key ecosystem services and promoting socioeconomic development.

Straw removal for bioelectricity, cellulosic ethanol, or other bio-products has become a common practice in Brazilian sugarcane areas, but long-term effects on soil organic carbon (SOC) and yield are unknown. Our objective was to quantify tillage intensity and removal levels on SOC stocks and sugarcane yield on contrasting edaphoclimatic conditions in Brazil. Conventional tillage-CT and reduced tillage-RT coupled with three straw removal levels (none—NR; moderate—MR; total—TR) were combined to create six treatment combinations: CTNR, CTMR, CTTR, RTNR, RTMR, and RTTR, respectively. Sugarcane yield was measured annually and soil samples to a depth of 40 cm were collected and analyzed before and after 5 years of treatments. Neither tillage practices nor straw removal significantly affected sugarcane yield on sandy loam soil, but CTMR, CTTR, and RTTR showed substantial yield reductions on clayey soil. SOC stocks for RTNR increased by as much as 1.64 Mg ha⁻¹ year⁻¹ on clayey soil, while CTMR and CTTR favored depletion of SOC stocks on both soils. Overall, each Mg of straw returned to the soil increased SOC stock by 95 kg ha⁻¹ for clayey soil under both tillage practices and 55 kg ha⁻¹ for sandy loam under the CT system. Furthermore, straw removal decreased microbial biomass C and b-glucosidase activity. These findings suggest that the adoption of RT attenuates the adverse impacts of straw removal on SOC stocks while ensuring sugarcane yields for a more sustainable bioenergy production in Brazil.

Sugarcane straw is a crop residue that has a dual purpose and can be maintained on the fields or used to produce bioenergy. The straw retention in the field provides multiple ecosystem services, and the complex interactions between straw and yield responses are hard to predict by local studies. The aim of this study was to investigate the straw removal effects on sugarcane yield in south-central Brazil. To achieve the objective, a set of 21 field studies was conducted in contrasting edaphoclimatic conditions. In addition, data of seven studies from the literature were included to build a more robust dataset. Since straw removal treatments were not homogeneous in all experiments, they were grouped as follows: NR, no removal (baseline treatment); LR, low removal; MR, moderate removal; and TR, total removal. To facilitate the data analysis, the experiments were gathered in four macroregions: southern Goiás, western São Paulo, central-eastern São Paulo, and northeastern São Paulo. The site location was the most effective individual factor to explain the straw removal effects on sugarcane yields. Compared with NR treatment, the average yield losses induced by LR, MR, and TR were 2, 10, and 13 Mg ha⁻¹ in southern Goiás and 2, 4, and 6 Mg ha⁻¹ in western São Paulo states, respectively. In other regions, no clear pattern was observed, and only site-specific effects were observed. Straw removal affected sugarcane yields in all soil types, but higher responses were observed under best conditions for sugarcane growth (i.e., clayey soils in southern Goiás). Our findings indicated harvesting season has a relevant role on determining yield responses to straw removal and younger ratoons are more responsive to straw removal. Conclusions from this study suggest straw removal recommendations cannot be designed based on isolated factors but require holistic and integrated knowledge to ensure that the straw amount left on field is enough to sustain multiple soil ecosystem services and crop yields.