Soil Quality Changes in Response to Long-Term Pineapple Production in Costa Rica.

Pineapple production has become increasingly important in Costa Rica, with plantations ranging in age from a few years to several decades. Production typically occurs on highly weathered soils, which have low pH, low nutrient status, and low cation exchange capacity.  The soils often have significant anion exchange capacity.  Soil samples were collected at a pineapple plantation in Costa Rica, from a young site of 7 years and in an older site of 20 years. Fertilization is primarily by foliar application. All organic residue is tilled into the surface soil after each crop cycle. Soil was also sampled at a pasture and a secondary forest site bordering the plantation. Samples were collected at each site to a soil depth of 20 cm and sectioned at 0-10 cm and 10-20 cm depth intervals. Soils were analyzed soils for pH, exchangeable acidity, basic cations, CEC, AEC, and organic carbon. A comparison of the soil data from the 7-year old pineapple field to the 20-year old field, indicates that there are no differences between the plantations of different ages in soil carbon and cation nutrients. However, exchangeable acidity was significantly elevated in the older pineapple field. Results suggest that although soil C and cation nutrients are not impacted by long-term pineapple cultivation, an increase in soil acidity can occur and management may need to be altered to maintain the soil quality.