Evaluating the environmental profiles of winter wheat rotation systems under different management strategies.

Climate change poses a remarkable challenge to global food security, for which wheat is one of the main staple agricultural commodities. The cultivation of different varieties of winter wheat in Galicia (commercial and native) under rotation systems with potato, maize and oilseed rape was evaluated from an environmental point of view. The general approach of this study included the gathering of the inventory data of the different crops, the quantification of their environmental impacts and economic benefits, to identify the best land management system. Life Cycle Assessment (LCA) was used as environmental tool. The environmental profiles of each rotation system were reported in terms of nine impact categories. Crop rotations were analysed both per hectare and per € of gross margin, so that the information can be relevant to land-management decisions. Preference ranks were established based on an environmental normalized score for both units. The results suggest that arable operations contribute decisively to the environmental profile of the rotations. The avoided mineral fertilization processes, the carbon storage in the soil when returning straw to the field, as well as the electricity production clearly influence the environmental impact of the rotations. Scenarios that include native wheat under organic management are always the environmentally preferred ones while the preferred alternate crop depends on the reference unit. Concerning the margin gross, scenarios including the native variety report the highest profits, being the potato the preferred alternate crop. Further assessment needs to be undertaken to identify differences in the results of different ways of conducting LCA, i.e. attributional vs consequential approaches.