We then sought to relate the observed patterns of community composition to the environmental variables. The distLM analysis identified the particle size (clay, silt and sand), pH, soil humidity, and some nutrients (nitrogen, phosphorus, calcium and magnesium) to be the best predictors of the bacterial and fungal community composition (Figure XX). The model successfully explains the main trends of the bacterial and fungal variance displayed in the constrained ordination (Figure XX).
As depicted by the fungal dbRDA, particles size (clay, silt and sand), humidity, pH, calcium and phosphorus clearly discriminate the fungal communities between the silt and the sand site. The discrimination between the organic and conventional farming, however, is not obvious: magnesium seems to be the best variable to separate conventional from organic farming. Regarding the bacterial dbRDA, there was also a clear discrimination between the silt and sand site mainly drove by the particle size (clay, silt and sand) and humidity. Here, pH, calcium and phosphorus were good predictors of organic farming at the silt site, while magnesium seems here again to be the best to separate conventional from organic farming.