Greenhouse gases assessment of soybean cultivation steps in southern Brazil

This study presents a greenhouse gases emissions assessment of soybean cultivation in southern Brazil based on life cycle inventory. Although there are currently some studies on this topic, it is focused in the country level. Nevertheless, there are differences among the producing regions and it's estimated that for each 20 kg of soybeans produced in Brazil, one is produced in Rio Grande do Sul state. In a previous study, a life cycle inventory of soybean cultivated in this Brazilian state was developed, nevertheless, the influence of land use change along the life cycle was not taken into account. Therefore, the current study discusses the influence of direct land use change over the greenhouse gas emissions. The functional unit (FU) employed was 1 kg of soybean harvested for a cradle to gate study. For the soybean cultivation, in the scenario related to no land use change (scenario 1), 0.352 kg CO2/FU was emitted. This value increases up to 205% in scenario 2 (in this case, the actual scenario was that 15.4% of soybean cropland area replaced grassland) and 892% in scenario 3 (all land transformation was over forest). In scenario 1, soybean cultivation was responsible for the higher share of the greenhouse gases emissions (42%). The highest contributions in soybean cultivation for greenhouse gases emissions were: liming (37%), fertilization (19%) and seeding (9%).