Anotace:
Fertilization and soil tillage have an important position in agriculture, because the modification and availability of nutrients from the soil to plants, as well as heavy metals are related to these mentioned treatments. The main negative impact of heavy metals on the environment is their non-degradability. In our study, the samples of barley grits were analysed, where chromium and nickel contents were determined depending on different agrotechnical methods of growing cereal plants. The field trials were based on a plot of land in the cadastral territory of Dolná Malanta near the city of Nitra in the Slovak Republic. The plot area was 14 m2. In the experiment, three different dosages of macroelements into the soil were applied, and two methods of soil treatment by ploughing were also performed. Barley grits were obtained by grinding of grains of four varieties of spring barley: KM2084, Lédi, Xanadu and Marthe. The lowest content of chromium and nickel in barley grits was determined in the KM2084 variety. The amounts of chromium in the barley grits of our tested samples were in the range 0.17-0.77 mg.kg-1 dry matter and nickel 0.05-0.76 mg.kg-1 dry matter, respectively. According to the Food Code of the Slovak Republic, the maximum permissible amount of chromium (0.77 mg.kg-1) was exceeded, mainly in the Lédi variety, in the case of nickel, its exceeding of the maximum permissible amounts (0,76 mg.kg-1) was not determined in any variety. NPK fertilization in the ratio 16:1:4 (70 kg N ha-1) in combination with minimization ploughing, as well as fertilization in the ratio 2.5:1:1.5 (60 kg N ha-1) in combination with conventional ploughing had an effect on an increase in chromium contents in barley grain in all varieties, but at the same time caused a decrease in nickel contents, except for the Xanadu variety. The same values were determined in the fertilized variant with the addition of limestone after the application of conventional ploughing. The application of conventional ploughing on unfertilized areas had an effect on the increase of nickel contents in all varieties and the decrease of chromium contents in three varieties of spring barley.