Chemical analysis of soil affected by fungal fronts of FFRs. Data from a total of 180 published FFRs and additional data from 13 FFRs of Calocybe gambosa, Agaricus arvensis, and Agaricus crocodilinus in Italian grassland/woodland. Data were collected as chemical parameters in the fungal front and outer areas with a high density of mycelial mats and soil external to FRs, respectively. Collected data were converted to mg kg-1 (ammonia, nitrates, phosphorous, potassium, magnesium, calcium) or % (total organic carbon, total nitrogen, pH, water content), Data were log-transformed to reduce dimensionality. Values of n represent the number of FFRs where soil chemical variables were studied.