*2.2. Data Collection*

In Italy, the collection of data on each production system was obtained through interviews and surveys. A detailed interview was conducted with the respective farm mangers to obtain initial information on cultivation and managemen<sup>t</sup> practices at each farm (Figure 1). Information on the description of the production systems, inputs used, and the managemen<sup>t</sup> practices were gathered from the managers of the respective farms. Data was collected on animal and plant production, seed use, use of fertilizer or plant protection products, field size, irrigation, machinery use, and if any recent changes have been made to the farm practice within the past five years.

**Figure 1.** General flow diagram of olive production systems in Italy.

In Italy, three olive-based agroforestry systems were compared with a conventional olive production system in Italy, with a yield of 4300 kg ha−<sup>1</sup> described in detail in the Ecoinvent database 3.3 [21]. The Ecoinvent database is the world's leading life cycle inventory (LCI) database, which provides well-documented data for thousands of products including agricultural processes.

In Denmark, input and production data were taken for the conventional wheat production system and combined food and energy system in Denmark from a previous study on the system [19]. Data collected included yields, field size, seed use, use of fertilizer or plant protection products, irrigation, machinery use, field preparation and, if any, recent changes made to the farm practice within the past five years (Figure 2). The combined food and energy system was compared with conventional wheat production system with a yield of 7341 kg wheat ha−<sup>1</sup> and application of fertilizer, pesticides, and herbicides according to Danish standard practice as per the description provided under the study sites.

**Figure 2.** General flow diagram for the combined food and energy production system in Denmark.
