Spatializing the carbon footprint calculation of an almond orchard through a geographic information system-based toolbox

As a carbon fixating activity, agriculture can offset CO2 emissions and should be assessed by calculating and monitoring the carbon footprint (CF) of the plant-soil-environment systems. The aim of this research is to develop a CF assessment tool for almond (Prunus dulcis) orchards. Validation was tested on a 3-year-old non-bearing commercial almond orchard with cultivar ‘Penta’ in central Spain. A carbon balance model (CBM) was adapted from the one previously developed in the framework of an EU Life project (ClimaTree), and was used with a Geographic Information System toolbox (i.e., ArcGIS). The CBM calculates the annual CF from the use of fossil fuels and electricity, fertilizers, and other agrochemicals, and then subtracting the CO2 removed from the atmosphere based on the production of fruit, generated wood and groundcover biomass, and the soil potential organic C storage. For the considered period (6 months), the results of the study showed a CF of – 3.74 t CO2 ha-1, which breaks down into a CO2 removal of 4.58 t CO2 ha-1 and a total emission associated with the cultivation of 0.84 t CO2 ha-1. The production of wood contributed the most to the CO2 removal (3.99 t CO2 ha-1, 87%), followed by the soil C storage (0.59 t CO2 ha-1, 13%). The highest CO2 emissions were associated with the use of pesticides (0.40 t CO2 ha-1, 49%), followed by fertilizers (0.29 t CO2 ha-1, 36%) and fossil fuels and electricity (0.13 t CO2 ha-1, 15%). Additionally, the use of a GIS-based model allowed evaluating the spatial variability of CF, which presented, a high homogeneity in terms of wood removal potential, whereas a heterogeneous pattern was observed for soil C storage and CF. In conclusion, the present GIS-based toolbox seems useful and user-friendly for calculating the CF, including their spatialisation. This application could help to precisely evaluate the impact of different cultivation management strategies in almond agro-ecosystems carbon balances.