Effect of neutralising substances on reducing the influence of cobalt on the content of selected elements in soil

The objective of this study was to determine the effect of cobalt on the content of total organic carbon, total nitrogen, the available forms of phosphorus, potassium and magnesium and the C:N ratio in soil, following the application of neutralising substances. The effect of cobalt in soil was tested on oats (Avena sativa L.). In order to limit the effect of cobalt, the soil was enriched with neutralising substances, i.e. manure, clay, charcoal, zeolite and calcium oxide. In the series with no neutralising substance, the increasing doses of cobalt only caused an increase in the amount of the available potassium, and the highest Co dose favoured an increase in the organic carbon content and a wider C:N ratio in soil. All the substances affected the content of the available potassium in soil, with charcoal, and especially manure, contributing to its elevated accumulation. Besides, manure fostered a growth in the soil content of the available phosphorus, charcoal - the content of organic carbon and the available potassium, and zeolite - the total nitrogen content, while calcium oxide promoted a higher content of total nitrogen and the available phosphorus. Clay and charcoal (unlike zeolite) caused the widening of the C:N ratio in soil.