After an initial soil sampling in the pilot farms, a battery of physicochemical and biological parameters related to soil health have been analysed in the IRNAS laboratories, allowing us to establish a diagnosis of the state of the soil in each of them. It is important to highlight that the sampling has been very satisfactory, since the replicability of the samples has been very high and we have a very well-defined starting situation that will allow us to detect differences in soil health as a consequence of the actions of the project once it has been completed.
The following conclusions are worth mentioning:
- All soils show pH values around 6, a very characteristic value for acid soils in the south of the Iberian Peninsula.
- Nitrate concentration is similar among all pilot farms.
- Phosphorus concentration is rather low, typical of grassland soils, with the exception of Valcorchero, which shows high values probably due to recent fertilisation practices on the farm.
- The Portuguese farms show the highest values of organic matter, microbial biomass and enzymatic activities, which are indicative of good soil health, in contrast to the dehesa of Siruela, which shows very low values, indicative of a high state of degradation.
- In relation to pathogens, the fungus P. cinnamomi has been detected in Siruela and San Francisco.
Some parameters are still to be analysed, although the results obtained so far show a good sampling and an impeccable experimental design that augurs interesting conclusions about the role of shrubs in the health of the soil in the dehesas.