Soil health indices: contributions to the evaluation of agroecological family farms within participatory guarantee systems

Soil health was evaluated on twelve agroecological family farms integrated within the participatory guarantee system (PGS) of the Agroecology Network of Uruguay. Two complementary indices were constructed: (i) the soil state index (SSI) and (ii) the index of agroecological management practices (IMP). These indices were built from qualitative indicators weighted according to expert judgment and aggregated into an area-weighted average for each land use type. Farms were grouped into three management levels (low, medium and high IMP). The SSI, based on soil properties that remain stable over time, showed low variability across farms and was therefore of limited use for assessing short-term management change, although it remained valuable for characterizing the inherent potential and limitations of each farm’s soils. In contrast, the IMP was more sensitive to management practices and better distinguished differences among farms. The structure of land use and the specific management practices applied within each use jointly explained the variation in the IMP. A significant positive correlation was observed between the IMP and an independently developed farm biodiversity index (Pearson r = 0.79), confirming a functional relationship between biodiversity and soil health. The methodology was applicable in the context of participatory certification, allowing the identification of strengths and opportunities for farm improvement.