Energy equilibrium and Carbon dioxide, Methane, and Nitrous oxide-emissions in organic, integrated and conventional apple orchards related to Natura 2000 site

Energy flow in apple orchards related to Natura 2000 sites can help to determine the best management strategies. Apple orchards found in or out Natura 2000 site, were selected in order to (a) determine energy equilibrium among farming systems, (b) reveal groups of orchards on the basis of their similarities to energy inputs, (c) estimate gas emissions, and (d) clarify the role agriculture to habitat conservation within Natura 2000 site. Seventeen farms (six conventional, seven integrated, and four organic) were selected. Hierarchical cluster analysis revealed three groups of the studied apple orchards. Group 1 (four conventional and three integrated orchards) had the highest energy inputs, while Group 3 (all organic orchards) the lowest. The highest contributors in cluster formation were insecticides, herbicides, and irrigation. Fruit production (41,189.1 kg ha−1) and energy outputs (98,853.9 MJ ha−1) were the highest for Group 1. Energy use for herbicides (0.0 kg MJ−1) and renewable inputs (35,673.8 MJ ha−1), energy efficiency (0.7) and productivity (0.3 kg MJ−1), and renewable energy efficiency (1.4) were the lowest for Group 3; but renewable energy consumption (1.82 MJ kg−1), intensity (3.6 MJ kg−1), and energy use for insecticides (213.5 kg MJ−1) were the highest. The largest contributors for gas emissions were fuels (46.4%) and fertilizers (20.9%). Organic orchards all located in Natura 2000 site (Group 3) had the lowest gas emissions (2.72 Mg ha−1 CO2, 0.68 kg ha−1 CH4 and 0.25 kg ha−1 N2O). Agricultural policies should regulate the balance between Natura 2000 sites and agriculture. Local management practices mainly affected the grouping of the study apple orchards revealing their importance for the development of agro-environment plans and for the influence on Natura 2000 sites.