Desempenho agronômico de Mentha aquatica cultivada em sistemas alagados construídos sob diferentes taxas de aplicação orgânica

Abstract

Taking account to the scarcity of information about the behavior of Mentha aquatica specie when cultivated under waterlogged conditions and high organic concentrations, aimed to evaluate the effect of different organic loading rates (OLR) on productivity and nutritional status of the specie cultivated in constructed wetlands (CWs) of subsurface horizontal flow in the treatment of sewage. Two CWs measuring 24,0 m x 1,0 m x 0,35 m, filled with "zero" crushed stone up to 0,20 m high layer, were planted with the specie. The experiment was conducted in two stages: in the first, OLR of 40,35 kg ha-1 d-1 and 53,80 kg ha-1 d-1 of BOD5 were evaluated; in the second stage, OLR of 79,66 kg ha-1 d-1 and 160,35 kg ha-1 d-1 of BOD5. At the end of each stage, samples of plant shoots were collected to quantify dry matter yield and to analyze the content of nitrogen, phosphorus, potassium and sodium in the leaves. Although cultivated under waterlogged conditions, the specie showed high productivity. The increased in OLR applied in the systems favored the dry matter production and increased leaf concentration of nitrogen, potassium and sodium.