The objective of this study was to evaluate the filter cake and peat as sources of organic matter in order to mitigate contaminated soil with boron, under the cultivation of turnip (Raphanus sativus). The studied soil was contaminated by the disposal of metallic waste rich in B which increased the total content of B (62.1 mg kg-1), and its availability (8.0 mg dm-3). The soil received application of 10 t ha-1 of limestone as recommendation of the environmental agency of the State of São Paulo, and the pH value increased to 7.5. The experimental design was completely randomized in a factorial scheme 2 x 4, with three replicates. The doses of each organic material added were based on the content of C, being equivalent to 0, 20, 40 and 80 t ha-1. In each experimental plot, pots containing 5.0 kg of contaminated soil was cultivated with ten plants each of turnip. The plants showed no symptoms of toxicity, although high levels have been observed in the leaf + stem (367 to 646 mg kg-1), and pod (119 to 180 mg kg-1). The indices F, IT, and the removal indicated the feasibility of phytoextraction of B by turnip. According to these indices, to remove 50% of the total B content of soil, it would be necessary 10.6 years without using OM, 15.4 years using peat, and 9.3 years using filter cake. It was concluded that the filter cake was considered amendment to the contaminated soil, and that the turnip has the potential to be grown in the contaminated area.
Raphanus sativus; organic matter; remediation of soils
