Effects of Live Stakes (Spondias mombin vs. Erythrina sp.) on Soil Properties, Biota and Yield in Hylocereus undatus Agroforestry Systems in the Ecuadorian Amazon

Agroforestry systems with live stakes have been proposed as management strategies to enhance soil and canopy-related processes in perennial crops. However, their integrated effects on productivity under Amazonian conditions remain poorly understood. This study evaluated the role of live stakes as modulators of soil and canopy conditions in Hylocereus undatus cultivated in the Ecuadorian Amazon. The field study lasted three years and used live stakes (Spondias mombin and Erythrina sp.) and an inert concrete stake. S. mombin exhibited the highest annual biomass contribution (14 t ha−1 year−1), approximately double that of Erythrina sp., and a higher abundance of earthworms (20 individuals m−2), suggesting greater soil biological activity. Canopy-mediated conditions differed among stake systems, with shade levels progressively increasing over time and reaching up to 67% under S. mombin. However, the crop’s physiological response, assessed through leaf relative chlorophyll content, was dominated by seasonal variability and did not show structural differences among the systems. Yield was comparable between S. mombin and the inert stake (18–20 t ha−1) and lower under Erythrina sp. (14 t ha−1). Overall, live stakes influenced system functioning, defined here as the combined response of soil biological indicators (earthworm abundance) and canopy-related indicators (shade percentage and relative chlorophyll content) in relation to yield. Although these effects did not translate into increased yield under the evaluated conditions, they may contribute to improvements in soil quality and biological activity over longer time scales.