Many coffee agroecosystems in Latin America have been transformed with the goal of maximizing yields. In these intensively managed farming systems, inorganic fertilizers are commonly used, with important agronomic, economical and ecological consequences. This study reviews the relationship between fertilizer application, coffee yield and quality indicators and soil chemical properties in coffee farms of the Los Santos region in Costa Rica. The mean nitrogen (N) input rate in farms employing inorganic fertilizer was 21216.7 kg ha -1 y -1. Yield reported by farmers had a positive marginally significant relationship with nutrient application rates. Cup quality attribute responded positively to calcium oxide (CaO) applications. Variables related to production and quality indicators were number of fungicide applications, soil exchangeable calcium (Ca) and acidity, elevation of the terrain, and number of stems per plant. Soil exchangeable Ca was positively correlated with the ratio of crop yield per unit of applied N fertilizer. In those farms with higher N input rates, soil pH was significantly lower. We suggest that the N saturation hypothesis developed for temperate forests under N atmospheric deposition is applicable to this perennial agroecosystem. This hypothesis predicts changes in the soil chemistry and nutrient retention capacity, and a reduction of Net Primary Productivity (NPP).
