Effects of agrotechnical treatments on spectrophotometric properties of humic acids in albic luvisols
2009
Kondratowicz-Maciejewska, K., University of Technology and Life Sciences, Bydgoszcz (Poland)
The objective of the investigations was to evaluate effects of agrotechnical treatments on physicochemical properties of humic acids of brown podzolic soils. Crop rotation appeared to be the basic factor affecting the optical density properties of humic acids. Rotation of crops enriching the soil with organic matter caused higher absorbance values of HAs solutions than in the one depleting the soil. Higher values of A2/4 and DELTAlog K parameters in crop rotation B indicated that HAs isolated from the soil supplemented with organic matter had a higher content of humus at the start of decomposition than HAs of the variant depleting the soil. The kind of crop rotation modified spectroscopic parameters of HAs. Humic acids of the soil under rotation of crops introducing less organic matter had a higher percentage of lignin structures than those of the other crop rotation. As compared with mineral fertilization, FYM fertilisation triggered a development of HAs of a smaller molecular weight. A clear presence of absorption bands in the range 1460-1000 cm-1 in the IR spectra of humic acids separated from the combination enriching the soil with organic matter showed their chemical youth.
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