Portugal is an European country situated at the south-west point of Europe and comprises the mainland and the Madeira and Azores archipelagos in the Atlantic Ocean. Mainland has a total area of 92.090 km2 (9222.56 thousand hectares), occupying ~16% of the Iberian Peninsula it shares with Spain. Resident population is about 10 million (10.295,909 persons) and the capital Lisbon has the greatest population density, with ~2 million people living in the Lisbon metropolitan area. (Nacional Statistics, 2019).
The agricultural land in Portugal occupies 3.9 thousand hectares, that correspond to 43 % of the territory. The main crop produced is tomato, both for industry and for fresh consumption (~ 97.613 kg/ha and 75.842 kg/ha respectively). Regarding animal production, poultry is the most abundant species (54.503,176 heads) followed by swine (~2.213,742 heads) (Nacional Statistics, 2019).
Portugal has advantageous conditions that allow a diversity of agricultural production across the country. This is the result of two climatic typologies present in the country mainland: Mediterranean like climate in the Southern part and Atlantic influenced climate in the Northern half of the country. Mild winters and hot summers favour a diversity of agro forestry and livestock activities, mostly produced extensively and in a diverse farm typology.
Historical inappropriate agricultural practices have played a big role in soil erosion as well as in soil organic matter depletion over the last decades. Nitrogen (N) is mostly found on the topsoil and due to this soil loss – and, consequentially, N loss - large-scale use of N supplements in agricultural systems is increasing. Additionally, climate change is leading to an increased aridity index, particularly in the south, therefore increasing susceptibility to desertification, with lower water and nutrient-retention capacity, which promotes a higher use of nitrogen fertilizers, with a related increase in N losses.
The N footprint (NF) estimation in Portugal considers the sectors of energy consumption from households and transports, food production and food consumption. Final NF in Portugal is overall 27.9 kg N cap-1 yr-1 for the last year of available data (2018). Around 80% of the total footprint is from food production, followed by food consumption, transport and housing. The food product with a higher contribution to this result is bovine meat.
Figure 1. Total Nitrogen footprint for Portugal per sector (2013 – 2018).
Although food consumption patterns in Portugal do not follow the traditional Mediterranean diet (MD), many dietary behaviours in Portugal still stand on the typical MD characteristics. This is particularly true for the diet composition but has suffered considerable deviations when it comes to the recommended portions. The MD is represented in the food wheel on figure 2 and is highly based on vegetables, fruits and cereal consumption and less on animal-based proteins. The current diet used in Portugal is found to consist of high protein content meals, with up to 47.7% of the total protein consumption.
First estimations allowed to highlight that food consumption and production NF in Portugal can achieve a reduction of 44% and 69%, respectively, by following the Mediterranean dietary recommendations. Mediterranean diet can reduce the impact on the final N footprint helping to mitigate N losses into the environment, not only in Portugal but across other Mediterranean countries.
Figure 2. Food wheel for the Mediterranean diet (Food wheel guide, 2003. Faculty of Food Sciences and Nutrition - University of Porto, Portuguese Consumer’s Institute. http://www.fao.org/3/ax433o/ax433o.pdf ; http://www.fao.org/3/ax403o/ax403o.pdf)