Influence of plant species on physical, chemical and biological soil properties in a Mediterranean forest soil

In semiarid ecosystems plant cover plays an important role in the improvement of physical, chemical and biochemical soil properties. With the aim of studying the influence of different plant species on soil properties, and establishing the relationships between them, 160 soil samples from under four different plant species (Pinus halepensis, Quercus coccifera, Juniperus oxycedrus and Rosmarinus officinalis) were taken in a forest area of the province of Alicante (SE Spain). The following soil properties were analyzed in all soil samples: organic carbon content, microbial biomass, soluble organic carbon, aggregate stability, basal respiration, and some eco-physiological ratios. In addition, the near infrared spectra (NIR) of all soil samples were obtained to verify the similarities or differences between soil samples under the four species. Some differences in parameters such as organic carbon content or basal respiration were found mainly between the group of P. halepensis and Q. coccifera with respect to J. oxycedrus and R. officinalis. Despite this, the high organic carbon content found under the four plant species showed an influence on the rest of soil properties. Moreover, using a discriminant analysis with factorial scores from NIR absorbance data did not result in a good classification of samples in terms of the species, reflecting some similarities between them. Our results show that the high contents observed in some parameters under the four species, and the lack of significant differences in most of them, prove the important role of shrubland in semiarid conditions, it being capable of promoting good soil conditions.