Agronomic Management, Socioeconomic Factors, and Carbon and Nitrogen Pools in Avocado–Coffee Systems in Huatusco, Veracruz, México

Avocado cultivation is displacing traditional coffee production in Veracruz, Mexico. This change modifies the floristic composition and agronomic management (AM), both of which are affected by socioeconomic factors and generate variation in edaphic conditions. The objective of this research was to identify the socioeconomic variables that modify the characteristics of the AM of avocado and coffee systems and have repercussions on the carbon and nitrogen pools. Four case studies were analyzed: a renovated coffee polyculture (SRC), severely cleaned coffee polyculture (IPC), avocado–coffee system (ACS), and conventional avocado orchard (CAO). A socioeconomic analysis was carried out with a 30-year economic projection and 56 variables. Three plots were installed where vegetal biomass carbon (VBC) was evaluated; soil samples were taken in theses plots at three depths (in triplicate) to determine soil organic carbon (SOC) and total soil nitrogen (TSN) in each case. A principal component analysis (PCA) was performed. Four economic variables explain 50.9% of the variation in agronomic management and five social variables 50.2%, in both cases where the component is considered. In all systems, the variation in VBC is explained by the agronomic management, while the reported SOC presents an inverse relationship with AM. The ACS presents the higher values in total C in the system, and SOC and TSN pools, while the CAO shows negative impacts concerning soil organic matter quality. The ACS is sensitive to investment, market diversity, education, and external organic residue addition, explaining the variations in AM and the TSN pools.