ARBUSCULAR MYCORRHIZAS IN SUGARCANE UNDER PLANTING SYSTEMS AND SOURCES OF NITROGEN

Abstract

The aim of this work was to evaluate the density of spores and mycorrhizal colonization in roots of varieties of sugarcane (RB86-7515, CTC-4 and CTC-15), under planting systems, being the planting of stem portions and pre-sprouted seedlings (PSS) along with 3 sources of nitrogen: granular fertilizer, leaf application and inoculation with diazotrophic bacteria (Azospirillum brasilense). The experiment was deployed on the experimental campus of the Evangelical School of Goianésia, and were collected soil samples for spore count after the first cut. The experimental design was arranged in factorial 3x2x3 in randomized blocks with subdivided plots using 4 repetitions per treatment, where factor 1 was represented by varieties, factor 2 by planting systems and factor 3 by nitrogen sources. The planting of PSS associated with foliar fertilization and A. brasiliense presented better colonization that in PSS with granular fertilizer and stem portions with leaf fertilizer and via inoculant. The granular fertilizer showed increased amounts of spores over the foliar fertilization and inoculation of Azospirillum brasilense, the planting system of stem portions presented greater quantity of spores over the planting of PSS, , it is worth mentioning that approximate results of spore density, mycorrhizal colonization and productivity without adding granular fertilizer are satisfactory for reducing the use of fertilizers.