PRODUÇÃO DE MUDAS DE ERVA MATE SOB NÍVEIS DE SOMBREAMENTO, ADUBAÇÃOE BIOESTIMULANTE

Abstract

The success of a commercial yerba mate (Ilex paraguariensis A. St. Hil.) plantation is directly related to the quality of the seedlings used. The objective was to study the effects of shading levels, mineral and organic fertilization and supply of aluminum and biostimulant on the initial development of yerba mate. Two experiments were carried out with yerba mate seedlings under greenhouse conditions: in the first experiment the shading levels and mineral and organic fertilization of the substrate (soil) were evaluated; and in the second experiment the soil-applied aluminum, soil-and foliar-applied fertilizers and foliar-applied biostimulant were evaluated. The bioestimulant was composed of the phytohormones kinetin, gibberellic and 4-indol-3-ylbutyric acid. Mineral fertilizations (controlled release granules and fertigation) were better than organic fertilizations (poultry and sheep manures and earthworm compost) for the development of yerba mate seedlings. The shading levels did not affect the growth of yerba mate seedlings, except in the treatment with controlled release mineral fertilizer + agricultural gypsum, in which there was better development of the seedlings under 70% shading. Soil fertilization increased the accumulation of macronutrients (N, P, K, Ca, Mg, and S) in the plants and was essential for the adequate development of shoots and roots of yerba mate seedlings, while sprays of foliar fertilizer and molybdenum did not affect nutrition and seedling development. The aluminum applied to the soil did not affect the growth and dry matter yield of shoots and roots and the seedlings showed a high capacity to accumulate this element in the roots. Foliar sprays with biostimulant resulted in greater growth of yerba mate seedlings. It is concluded that the soil mineral fertilization and the use of biostimulant via foliar sprays provide better development of yerba mate seedlings.