MICRORGANISMOS SIMBIONTES, MATÉRIA ORGÂNICA E ADUBAÇÃO NITROGENADA NO DESENVOLVIMENTO E NUTRIÇÃO DO MIRTILEIRO CV. CLIMAX EM AMBIENTE PROTEGIDO

Abstract

The blueberry is an agricultural crops recently introduced in Brazil and lots of researches are turning to develop and adapt it to the country. Due to its low amount of root hair, it forms associations with microorganisms to expand its zone of nutrient uptake, being the nitrogen the most required element. At this work it was observed the interaction of this cultivation with the inoculum Azospirilum brasilense and Trichodema asperellum into different substrates or doses of nitrogen fertilization. The experiment was performed with cv. Climax and the plants conditioned in pots in greenhouse, under trial design of randomized blocks, factorial 3x3. The considered factors were inoculation (A. brasilense, T. asperellum or without inoculation) and formulation of the substrates (5; 20 e 35% of organic matter – hardened cattle manure) or, at the second experiment, inoculation (A. brasilense, T. asperellum or without inoculation) and doses of nitrogen (0, 10 and 15 g f N plant-1 – provided as urea). The larger quantity of organic matter provided the highest averages relating to physiological (transpiration, water use efficiency and carboxylation efficiency) and growth variables (foliar limb area, total foliar area and rate of relative growth), although, for some of them, it has not differed from plants grown with 20% of organic matter. With 30% of O.M., the inoculation with T. asperellum showed superior averages in CO2 assimilation (A), carboxylation efficiency (A/Ci) and rate of relative growth (RRG). The nitrogen doses positively affected A/Ci, clorophyll amounts, foliar area (limb and total) and foliar nitrogen concentration, although it not differing between 10 or 15g of N plant-1. For the accumulation of the nutrients Ca, Mg, S, Fe and Zn, the nitrogen fertilization did not represent higher foliar levels, even though this might be related to a dilution effect.