Closing the Loop: Nutrient Balances in Organic and Conventional Coffee Agroforests

Agroforests are a primary example of ecologically sustainable agroecosystems due to their efficient use of natural resources and ability to buffer against ecological and socioeconomic stresses. We constructed nitrogen (N) and phosphorus (P) balances to examine the ecological sustainability of conventional, organic, and unfertilized coffee agroforests. A similar percentage of applied nutrients were recovered in conventional and organic coffee yields. However, nutrient excess (inputs minus outputs) was higher in conventional farms, suggesting they may be more prone to nutrient loss. Nutrient pools were large overall, with unfertilized farms tending to store nutrients aboveground, and fertilized farms belowground. Future research should investigate the fate of excess nutrients to develop specific strategies promoting nutrient optimization in agroforests.