Organic production in corn: impact of fertilization with landfill leachate in chemical composition, productivity and concentration of metals in grain

The use of landfill leachate in agricultural soils as fertilizer emerges as an alternative for the disposal of this effluent, however presence of heavy metals may be a limiting factor for that use. Fertilization with five doses of landfill leachate (0, 32.7, 65.4, 98.1 and 130.8 m3 ha-1) and urea (120 kg ha-1) was evaluated in productivity, chemical composition and metal content of corn in crops 2010 and 2012. The accumulation of metals in leaf tissue was also evaluated in oats grown in the winter period, in the same experimental field. Productivity, besides the content proteins, lipids and ashes in grains increased with increasing doses of leachate. Concentration of Ca, Mg, Na, K, Zn, Cu, Ni and Pb in corn fertilized with landfill leachate did not differ from control without fertilization, except for Mn, which increased by applying leachate (p > 0.05). Increasing doses of leachate tended to raise the level of Pb (2010 crop) were not observed in the same crop later, indicating that Pb concentration is dependent on intrinsic and extrinsic factors to the soil. However, content of Cu, Mn and Pb in leaf tissue oat increased with doses of leachate, suggesting potential use as phytoremediation system. Results show the need for further investigation before safe use of landfill leachate in agricultural soil.