Environmental Sustainability of Irrigated Sugarcane in Different Regions in Brazil.

Abstract:

Advancement of sugarcane into new areas has been done haphazardly and poorly planned, which has brought many negative consequences. Thus, irrigation has emerged as the major tool to increase the sugarcane yield, especially in regions with higher water restrictions. Few studies have discussed the environmental impacts of irrigated sugarcane in terms of greenhouse gas (GHG) emissions. This objective of this work was to evaluate the environmental impact of irrigation on sugarcane, taking into account GHG emissions under different production scenarios. By simulating the biomass production (Agroecological Zone) under rainfed and irrigation conditions in 6 regions of Brazil (Aracatuba/SP, Ribeirao Preto/SP, Paranaiba/MS, Itumbiara/GO, Paracatu/MG and Petrolina/PE), an inventory of GHG emission was performed using the IPCC (2006) methodology in order to identify variations on GHG emissions regarding the adopted irrigation systems, being the results expressed in terms of C footprint (in kg CO₂eq t^-1) to correlate GHG emission and sugarcane yield. Irrigation systems intensified environmental burdens and agricultural practices, since they consume more electricity, diesel and other inputs, especially synthetic N fertilizer, which is some of the major contributors of GHG emissions. Comparing the evaluated irrigation systems, Petrolina presented the highest variations in terms of C footprint (33.0 kg CO₂eq t^-1), followed by Paracatu (13.9 kg CO₂eq t^-1) and Paranaiba (12.0 kg CO₂eq t^-1). On the other hand, Itumbiara (10.8 kg CO₂eq t^-1), Aracatuba (9.6 kg CO₂eq t^-1) and Ribeirao Preto (7.1 kg CO₂eq t^-1) were those with the lowest variations. Our study highlights that the irrigation on sugarcane may represent a breakthrough in both economic and environmental concerns since technical and management aspects are strictly deemed.

Keywords: Saccharum ssp., C footprint, ethanol production, GHG inventory.

References:

IPCC, 2006. IPCC Guidelines for National Greenhouse Gas Inventories. In: Eggleston et al. (Eds.), IPCC National Greenhouse Gas Inventories Programme. Institute for Global Environmental Strategies (IGES), Hayama, Japan, p. 664.