Efeito da relação Ca:Mg do corretivo no desenvolvimento e nutrição mineral de mudas de aroeira (Myracrodruon urundeuva Fr. All.)

Abstract

An experiment was carried out in a greenhouse at the Soil Science Department, Federal University of Lavras, using pots containing 5kg of dystrophic Dark-Red Latosol, layer of 0-20 cm to evaluate the effects of Ca:Mg relation in lime on the development and mineral nutrition of aroeira (Myracrodruon urundeuva Fr. All.) plants. The applied amount of lime was determined by the method of base saturation up to 60%. The treatments consisted of five Ca:Mg relations (1:0; 1:1; 2:1; 4:1 and 8:1), which were established on the basis of equivalent milligrams using pure grade calcium and magnesium carbonates, and of calcium carbonate plus magnesium sulphate, magnesium sulphate only and a control. The treatments affected the plant growth and foliar contents of nutrients. With regard to plant height and stem diameter, the best results were obtained in the treatment with calcium carbonate plus magnesium sulphate, followed by lime with Ca:Mg relations of 2:1, 1:1 and 8:1, with the exception of the last one for stem diameter. Behavior was similar with regard to dry matter, with calcium carbonate plus magnesium sulphate giving rise to the greatest weights of 8.62; 4.27 and 10.63 g for roots, stem and leaves, respectively. The foliar contents of nutrients in the treatments that showed best responses varied from 21.1 to 25.1g kg-1 for N; 0.72 to 1.0g kg-1 for P; 13.7 to 16.6g kg-1 for K; 13.4 to 14.8g kg-1 for Ca; 2.2 to 4.3g kg-1 for Mg; 18.35 to 22.52mg kg-1 for B and 16.4 to 18.57mg kg-1 for Zn.