The micronutrients are important in the nutrition of the plants, especially in tropical ground with low concentration of these nutrients. As alternative source of micronutrients, have the basic slag, trash of the siderurgical industry. Thus it was objectified to evaluate the basic slag as source of micronutrients for guava plants. The experimental design was in randomized blocks with five replications. The doses of basic slag had been applied objectifying to raise in zero; half; once, once and half; twice and twice and half the dose to raise V =70%, corresponding the 1.68; 3.36; 5.04; 6.72 and 8.40g for pot, besides the witness without application. After 90 days of incubation of the basic slag with substratum (Ultisol), it was cultivated dumb of guava plants (cv. Paluma) per 110 days in pot with 2.8 dm³ of substratum. The basic slag promoted a positive effect in the reaction of soil and in the availability of Zn, Cu, Mn and B in soil. It had quadratic effect in the concentration of Zn, Cu and Mn in soil, that in turn, was associated with the doses of basic slag, superiors the 5.8; 6.3 and 7.5 g for pot respectively, while that for the B this effect was linear. The basis saturation in the soil between 51 and 55%, resulted in bigger availability of micronutrients Zn, Cu and Mn in soil, to the pacing that stops the B this value was of 65%. In the same way that occurred in soil, the application of the basic slag presented a quadratic effect in the concentration of Zn, Cu and Mn of the top plants and the roots, while that for the B this effect was linear.
Psidium guajava L.; basic slag; guava; micronutrients