FATE OF APPLIED MOLYBDATE IN ACIDIC SOILS

Sodium molybdate, at the rate of 10 ppm Mo, was added to the surface of seven acidic soils which were then stored moist for 3 to 10 months. After storage, less than 4 per cent of the added Mo was leached through any of the soils by the equivalent of a 250 mm rain. Between 36 and 91 per cent of the added Mo could be extracted with 0·1M NaOH, this proportion decreasing with longer incubation. Up to 40 per cent resisted treatment with both H2O2 and NaOH, and most of this was extracted with dithionite plus citrate. It is concluded that Mo is not lost by leaching from acidic soils other than sands, but is adsorbed on sesquioxide surfaces and slowly changed into less soluble forms. Copyright © 1969, Wiley Blackwell. All rights reserved