The Role of Relict Vegetation in Maintaining Physical, Chemical, and Biological Properties in an Abandoned Stipa -Grass Agroecosystem

Abstract

A study of rhizosphere physical-chemical and biological properties for dominant vegetation, including Stipa tenacissima and Rosmarinus officinalis, and for relict natural vegetation, namely Olea europaea subsp. sylvestris, Pistacia lentiscus, Retama sphaerocarpa, and Rhamnus lycioides, was carried out in an abandoned agricultural soil from a semiarid Mediterranean area. Rhizospheres of R. sphaerocarpa and S. tenacissima had the highest concentration of total N. Rhizospheres of R. sphaerocarpa and R. lycioides showed the highest soluble C-fraction values (water soluble C and water soluble carbohydrates). The highest percentages of stable aggregates were recorded in the rhizospheres of P. lentiscus (about 69%) and S. tenacissima (about 79%). O. europaea and R. sphaerocarpa had the highest capacity to enhance the development of mycorrhizal propagules in their rhizospheres. The mycorrhizal potential of S. tenacissima was on average 3.2-fold lower than that of O. europaea and R. sphaerocarpa, which points to the necessity ofreconstituting it prior to carrying out revegetation processes.