Linking Coffee to Soil

Abstract

Understanding the effects of soil health (SH) on the quality of high-value crops such as coffee may enable farmers to receive financial benefits prompted by product differentiation and price premiums. This study assessed the existence and nature of the relationship between coffee cup quality and SH. Soil and coffee seed samples were collected from 68 member-farms of a cooperative participating in a high-quality coffee value chain and 67 non–member-farms located across six municipalities in Cauca, Colombia, and 117 farms across two municipalities in Antioquia, Colombia. Elevation was recorded on each farm. Soil samples were tested for 13 SH indicators including wet aggregate stability, available water capacity, active carbon, organic matter (OM), protein, respiration, pH, P, K, Mg, Mn, Fe, and Zn. Coffee samples were tested by professional cuppers for physical, granulometric, and sensorial traits including fragrance/aroma, flavor, aftertaste, acidity, body, uniformity, sweetness, clean cup, and balance. Pearson correlation tests, principal component analysis, and canonical correlation analysis were conducted on all measured variables for Cauca and Antioquia separately and combined. Results show that coffee quality and sensorial traits tended toward a negative relationship with physical and biological SH, primarily with the indicators available water capacity and OM and the labile OM-related soil properties active carbon and respiration, whereas chemical indicators variably correlated with coffee quality. This suggests that coffee may be similar to wine grapes in that high-quality products not necessarily derived from soils with high values of SH indicators. The results of this study can guide further work to identify suitable management strategies that maximize coffee quality without significantly jeopardizing production or the environment.