The influence of soil treatment by untreated and composted tannery sludge on yield, nutrient status, and chromium content in selected crops

The research is aimed to determine the effect of fertilization with untreated or composted tannery sludge on yielding, macroelement and chromium contents in plant biomass. The biggest yield diversification was observed in the first and second year of the experiment, whereas in the subsequent years no major differences in yields were discerned. The mechanism of diversified plant response to organic fertilizers supplied to the soil resulted from their different ability to utilize nutrients but was also due to crop succession and different tolerance of subsequent species to the amount of supplied chromium. Nitrogen contents in plants were diversified, despite supplementing its dose to an equal level in all treatments (except the control). It may be concluded that the nitrogen in the applied materials occurred mostly in organic forms and its availability depended on the mineralization rate. Phosphorus and magnesium content depended on the plant species and applied fertilization. Potassium was more available if applied in a mineral form whereas calcium and sodium contents increased significantly in the plant biomass after fertilization with tannery sludge containing materials. Chromium content in tannery materials did not affect the content of this element in the aboveground plant parts and the absorbed chromium was retained mainly in the plant root system.