Effect of the Tillage System on the Properties of Humic Acids of Soil of the Kujawy Region in Poland

The aim of this study has been to determine the properties of humic acids of soil depending on the tillage system applied. The study covered the soil where plough tillage, strip-till and ploughless tillage were used, and so the systems which differed completely in the way they affect the post-harvest residue, “plant residue management”. From averaged samples of soil humic acids (HAs) were extracted to identify their elemental composition, spectrometric properties for the UV-VIS and IR range as well as hydrophilic-hydrophobic properties.

With the results one can conclude that the humic acids of the soil under plough tillage show a lower degree of humification as compared with HAs of ploughless tillage, whereas the parameters recorded for HAs of the soil with strip-till point to the similarity to HAs of soil with plough tillage and ploughless tillage. With that in mind, with some approximation, the degree of humification (maturity) of HAs can be ordered as follows: HAs with plough tillage < HAs with strip-till < HAs with ploughless tillage. Thus one can conclude that the tillage method combines two primary objectives; ensuring conditions favourable to plant growth and development and the effort to maintain the possibly highest humus stability.