Department of Agriculture, Calcutta University, Calcutta
*Present address: National Commission on Agriculture, Vigyan Bhavan Annexe, New Delhi
The humic andfulvic acids of Assam soil were investigated for complex formation with transitional metal ions in aqueous solution. The stability of the humic and fulvic acid metal ion complexes deduced from the potentiometric titration curves of the acids in presence of metal salt was of the order: Cu > Zn > Co > Mn. The decrease in intensity of fluorescence excitation spectra confirmed the formation of complexes which were more or less nonionic. Cu++ and Fe++ formed more stable complexes than Zn++, Mn++ and Co++.
Complexes of transitional metal ions, humic and fulvic acids
