CONCENTRATIONS OF NICKEL, LEAD an‎d CADMIUM IN RICE PLANT AS AFFECTED BY FARMYARD MANURE

The concentrations of cadmium (Cd2+), nickel (Ni2+) and Lead (Pb2+) in different organs of rice plant were investigated by field experiments. Data showed that the highest yield of rice grain was recorded by the application of 21.42 tons farmyard manure (FYM) plus 357 kg urea.ha-1 as compared with the other treatments. Roots accumulated more Pb2+, Ni2+ and Cd2+ than straw and grains at harvest stage of rice growth. Pb2+, Ni2+ and Cd2+ concentration in rice plant organs (root, straw and grain) increased with increasing levels of FYM either alone or in combined with urea compared with the control. Pb2+ concentrations in straw do not exceed the critical limits of pollution with FYM added to the soil either separated or combined with urea. However, rice grains were slightly polluted at 21.42 tons FYM plus 238 kg urea.ha-1 and 21.42 tons FYM plus 357 kg urea.ha-1. Ni2+ concentration in rice grain and straw do not exceed the critical limits with all treatments .Cd2+ concentration in rice straw do not exceed the critical limits of Cd2+ at all addition levels of FYM added to the soil whether levels separated or integrated with urea, however Cd2+ concentration in rice grain was polluted at 21.42 tons plus 238 kg urea.ha-1, 14.28 tons FYM plus 357 kg urea.ha-1 and 21.42 tons FYM urea.ha-1. Integration of 14.28 tons FYM plus 238 kg urea.ha-1 do not exceed the critical limits of the concentration of Pb2+, Ni2+ and Cd2+ in different organs of rice plant.