Introduction. In recent years, significant results have been obtained in Cuba in the joint management of efficient strains of arbuscular mycorrhizal fungi (AMF) and Canavalia ensiformis L., in different types of soils. However, there are no reports about the effectiveness of strains of AMF in Calcaric Histosol soils, which are highly represented in the central and eastern areas of the country. Objective. The objective of this research was to compare the effectiveness of four AMF strains inoculated in C. ensiformis seeds in in Calcaric Histosol soils. Materials and methods. Plants through seed coatings inoculated and a non-inoculated control were evaluated; C. ensiformis L. was used as plant host in a complete randomized design with four repetitions per treatment during two consecutive years. Sixty days after C. ensiformis seeding, the biomass production; N, P and K contents; percentage of total mycorrhizal colonization; and the reproduction of mycorrhizal spores were evaluated. Results. For all variables, there was a positive and differentiated response between the different strains, and the highest values (p≤0.05) were obtained with the inoculation of Rhizoglomus intraradices / INCAM-11. The high amounts of spores produced by the inoculation with R. intraradices / INCAM-11 were indicative of to the possibilities of using Jackbean as a way to introduce efficient strains in this edaphic condition. Conclusion. The results obtained allow to include Calcaric Histosol soils, with pH>7.5, in the group of soils in which R. intraradices / INCAM-11 behaves as an efficient strain.

A field experiment was conducted to study the effect of a Pseudomonas fluorescens-based biofertilizer on sweet potato (Ipomoea batatas (L) Lam) yield. The application was by immersion of cuttings before sowing for 0, 5, 10 and 15 minutes with combination doses of 0, 50 and 100% of NPK mineral fertilizer in a randomized block design with three replications (12 treatments-combinations). During the harvest (130 days after planting), some measurements related to yield components were recorded on ten randomly selected plants from each plot. All treatments with Pseudomonas’ immersion showed a positive productive response. With 100% NPK and the immersion in the biofertilizer for 15 min showed the highest yield (56.09 tha-1), followed by the other treatments with 100% NPK and without statistical differences among them. The treatment with 50% NPK and the immersion in Pseudomonas for 15 min (49.58 tha-1) had no statistical differences with the control variant (100% NPK, 51.60 tha-1). Based on the results, it can be concluded that this biofertilizer could be an appropriate alternative to increase the sweet potato yield, saving the 50% of the current quantity of the recommended mineral fertilizer, through a more friendly environmental techniques to promote a sustainable, efficient and productive agriculture.