Soil pollution by heavy metals has increased worldwide
and the search for plants that can be used to remediate
polluted areas is an interesting alternative. The aim
of this study was to evaluate the tolerance of tropical
grasses to Ni and its availability for the Mehlich 1, DTPA,
and USEPA 3051 and 3052 extraction methods in Nicontaminated
Oxisol.
Megathyrsus maximus
(Jacq.)
B.K. Simon & S.W.L. Jacobs ‘Aruana’ and ‘Tanzania’,
Urochloa brizantha
(Hochst. ex A. Rich.) R.D. Webster
‘Xaraés’ and ‘Marandu’, and
Urochloa decumbens
(Stapf)
R.D. Webster ‘Basilisk’ were grown for 90 d in a Typic
Hapludox (Oxisol) after adding 20, 40, and 120 mg Ni kg
-1
to the soil. Tropical grasses showed a positive response
to the application of Ni doses. The order of decreasing
tolerance of tropical grasses to Ni in the soil was: ‘Basilisk’
> ‘Xaraés’ > ‘Marandu’ > ‘Aruana’ > ‘Tanzania’ based
on the critical toxicity dose. Nickel concentration and
accumulation increased with increasing soil Ni doses in
all the tropical grasses. Mehlich 1, DTPA, USEPA 3051,
and USEPA 3052 Ni extraction methods in the soil are
efficient to diagnose Ni availability in tropical grasses.
