The effect of long-term organic–mineral fertilisation on selenium content and chosen oxidoreductases activity under winter wheat cultivation

The aim of the research was to determine the effect of fertilisation applying various doses of manure and nitrogen on the selenium content of soil against a background of soil catalase and dehydrogenase activity. The experiment was conducted using a crop rotation system of: potato–winter wheat+intercrop –spring barley+undersown and red clover+grasses. The soil was treated with organic fertilisation in the form of manure under potato at doses of 0, 20, 40, 60 and 80 t·ha −1, and with nitrogen at doses of 0, 40, 80 and 120 kg N·ha −1. A supplement of manure at 80 t·ha −1 resulted in the greatest significant increase in soil total selenium content of ∼100% compared with soil from control plots. We observed that interaction of the highest manure and nitrogen doses resulted in a significant decrease in the total selenium content of the soil. Selenium content in soil was statistically highly correlated with organic carbon content. Analysis of the correlation showed a significant dependence between the total selenium content in the soil and the activity of soil catalase and dehydrogenase.