To provide a general picture of how soil properties change during secondary succession, we collected soil samples from 21 secondary forest chronosequences across the Neotropics. For the 21 chonosequence sites, we sampled soils from active cropland or pasture (if possible), secondary forests that differ in age, and old-growth forest. To assess changes in soil conditions, we used six soil properties: pH, bulk density, total organic carbon (C), total nitrogen (N), extractable phosphorus (P), and the ratio between C:N.