Performance of two valuable species, Pinus pseudostrobus and Eysenhardtia polystachya, in a low fertility soil mediated by mycorrhizal fungi and fertilization

Abstract

Interspecific relationships are fundamental to maintain ecological processes, and are particularly important for the recovery of plant cover in severely degraded sites. An experiment was set up to evaluate pairs of Pinus pseudostrobus–Eysenhardtia polystachya plants, the first inoculated with Pisolithus tinctorius and the second inoculated with P. tinctorius and/or Rhizophagus intraradices, plus inoculation controls, and phosphorus fertilization. Growth and biomass were measured as response variables. For the pines, only height and number of branches responded to factors directly applied to the tree: fertilization and inoculation with Pisolithus tinctorius. However, these variables also responded to inoculation of the legume with Rhizophagus intraradices, implying an indirect effect on the pine plant. Furthermore, this indirect effect was significant for pine biomass accumulation. Fertilization had a positive and significant effect for the legume plants increasing the values for almost all of the variables (apart from branch length) but for some variables the simultaneous presence of both mycorrhizal fungi was detrimental. Different combinations of fertilization and inoculation benefit growth of the pines and the legumes. When environmental restoration of production systems is considered, either conditions favoring the legume can be achieved (if protection of the soil in the short-term is desirable), or conditions favoring the pines can be implemented (if favoring the tree species is preferable).