PRODUÇÃO DE SERAPILHEIRA, APORTES DE NUTRIENTES E ATRIBUTOS DE FERTILIDADE DO SOLO EM SISTEMAS AGROFLORESTAIS DE ERVA-MATE

Abstract

The exploration of erva-mate (Ilex paraguariensis St. Hil.), causes the export of considerable amounts of nutrients, once there are periodic removal of leaves and small branches for commercialization. The adoption of agroforestry systems (AFS´s)for the production of erva-mate assists in maintaining soil quality, due to the intense supply of litterfall. This study aimed to quantify the deposition of litterfall and nutrients coming from it, and the main attributes of soil fertility in AFS's erva-mate, it discriminating which soil attributes and nutrients via litter deposition allow to differentiate the AFS's erva-mate, and seeking relationships between soil chemical attributes and nutrients deposited. They were studied six AFS's production of ervamate in three different soil types, in the municipalities of São Mateus do Sul, Bituruna and Cruz Machado, in the South Central region of the State of Paraná. The canonical discriminant analysis (CDA) was applied to variables: soil attributes (pH, H+Al, Al,Ca, Mg, K, CT, P, S, Mn, Cu e Zn), for soil layers 0-5, 5-10, 10-20 e 20-40 cm; and variables annual deposition of the N, P, K, Ca, Mg, S, Cu, Mn e Zn. The study of the relationship between the supply of nutrients via litter deposition, and the levels of these nutrients in the soil were performed by canonical correlation analysis (CCA). The deposition of litterfall ranged from 7132 to 9402 kg ha-1 yr-1, and it was demonstrated an important source of nutrients, especially the deposition of N, K, Ca, and Mn. The CDA has pointed the contents of Cu and Al in the soil as responsible for discrimination of the sites. There is a close relationship between the deposition of Ca, Mg, Cu, Zn and Mn and the contents of these elements in the soils under AFS´s ervamate.