Early mycorrhization of two tropical crops, papaya (Carica papayaL.) and pineapple [Ananas comosus(L.) Merr.], reduces the necessity of P fertilization during the nursery stage

Abstract

Introduction . The use of mycorrhizal fungi as biofertilizers can reduce chemical inputs during the nursery phase, allowing the production of high quality plant material with reduced fertilizer inputs. The lack of complete knowledge of each crop’s responsiveness to mycorrhizal symbiosis, however, is still a handicap to the routine application of this biotechnology for commercial purposes. In our work, the influence of early mycorrhization as an alternative to standard P fertilization programs for two tropical crops, papaya and pineapple, was assessed in a greenhouse experiment. Materials and methods . Papaya seedlings and pineapple planting material were inoculated with the arbuscular mycorrhizal fungus (AMF) Glomus mosseae and cultured on substrates with increasing amounts of soluble P. Data concerning plant development and nutritional status were determined 5 months (papaya) and 7 months (pineapple) after inoculation. Results . For both crops, benefits derived from mycorrhization, expressed in terms of plant development and nutritional status, were significantly higher than those derived from P application. Overall, mycorrhizal papaya plants exhibited significantly higher biomass and macroelement contents in shoots than plants without mycorrhizas at any P level. Mycorrhizal effects on pineapple at the lowest P level were significant in terms of plant development and P shoot contents. Conclusions . Differential benefits derived from mycorrhization seem to be correlated to each crop’s internal P requirements. Our work highlights the potential benefits of integrating early mycorrhization at the nursery stage in order to reduce P fertilizer inputs in sustainable plant production systems.