In this 3-year-long study, significant impacts of biochar alone or in combination with nitrogen fertilization at different doses on the change in the soil chemical properties and grain yields of barley, wheat and corn were demonstrated in a field experiment established at the experimental station of the Slovak University of Agriculture in Nitra, Slovakia. Soil samples were taken from plots treated with biochar at different doses (0, 10 and 20 t ha-1) and with three levels of N fertilization (0, 1-st, 2-nd intensity of N fertilization) during the years 2014 – 2016. The results showed that the application of biochar had a positive effect on the increase of soil pH, as the soil pH rose with the increasing application doses of biochar. The effect of biochar and its combination with N fertilizer increased SOC in the range of 8 – 79%. The mean seasonal concentrations of NO3- and NH4+ between the different treatments were not significantly different. The NH4+ content in the soil was affected by the application of N fertilizers, but not by biochar. The application of biochar reduced the NO3- concentration in the soil. The ability of biochar to increase the grain yields over the monitored period ranged from 1% up to 42%, but this effect of biochar significantly diminished two years after its application to the soil. Biochar and biochar combined with nitrogen fertilization appears to be a promising practice to improve sustainability of intensive agriculture by enhancing chemical properties of soil (increase of soil pH and soil organic matter), although the effects on grain yields are not long-term ones.    

25.2.2020