Adubação química e orgânica na recuperação da fertilidade de subsolo degradado e na micorrização do Stryphnodendron polyphyllum

Due to the building of the Hydroelectric Power Plant of Ilha Solteira, in the late 60s, some areas have been deforested and were used as "loan areas". Thus, the soils belonging to these locations were subtracted and these areas' physical, chemical and biological properties became inappropriate. This work aimed at evaluating the use of chemical and organic fertilization to improve the degraded subsoil and replanting with mycorrhizal Stryphnodendron polyphyllum ("barbatimao"). The area is located at the Experimental Station (FEPE), UNESP/Ilha Solteira Campus, in Selviria - MS. Using the design of randomized blocks with four replications of 250 m2 plots (10 x 25 m), 10 treatments were evaluated: control; liming; fertilizing N + P; liming + N + P; N + P + water hyacinth; N + P + sugar cane bagasse; N + P + water hyacinth + sugar cane bagasse; liming + N + P + water hyacinth; liming + N + P + sugar cane bagasse; and liming + N + P + water hyacinth + sugar cane bagasse. Chemical characteristics of the subsoil and plant growth were evaluated five times (June, August, November and December 2005, and March of 2006) and the root percent colonization was evaluated in March 2006. After a year the subsoil still remained acidic and of low chemical fertility. The steam diameter and plant height showed increasing results along the period, with the highest values for the treatments that received liming, N + P and organic residues. The percent mycorrhizal colonization and number of spores were positively influenced by the presence of organic residues.