NUTRIENT EXPORTATION IN DIFFERENT PRUNNING SYSTEMS OF Ilex paraguariensis TREES

Abstract

The pruning system of the Ilex paraguariensis trees shows strong influence on the nutrients uptake. However, there is little information about these as well as about the replacement fertilization in some management systems. The objectives of this work were: (i) to quantify the nutrients uptake (N, P, K, Ca and Mg) for Ilex paraguariensis trees in different pruning systems, and (ii) to compare the N, P and K uptake values with the recommended by fertilization based on the soil analysis. The experiment was installed in Guarapuava-PR, in a 15 years old stand, with three blocks, being 12 plants sampled per plot. The treatments were five pruning systems: T1 - Cleaning Pruning, T2 - 70% Pruning, T3 - Reduction Pruning, T4 - 90% Prunning and T5 - “Schier”. The Reduction pruning treatment exported approximately 70%, 9.9%, 45.8% and 31.6% more biomass and nutrients (N, P, K, Ca and Mg) than Cleaning Pruning, 70% Pruning, 90% Pruning and “Schier” Pruning treatments, respectively. Related to the amount of nutrients recommended by fertilization based on soil analysis and the amount of nutrients exported by the leaves, it was observed similar results for N (“Schier” pruning) and K (70% Pruning and Reduction). However, the P values were not similar, regardless of the pruning system tested. In the 70% Pruning system, the most used in the region of Guarapuava-PR, was observed a deficit of 19.0% for N.