Waste sulfur from biogas desulphurization: a supplement of Brassica napus L. nutrition

The content of sulfur in soils has been declining. Possible option to supply sulfur into the soil can be utilization of waste sulfur from biogas production. Two pot experiments with identical treatments were established to examine the effect of waste sulfur from biogas plant applied solely and in mixture with other nutrients on the growth and yield of oilseed rape. The included treatments were control, waste elemental sulfur (S), S + boron (B), S + B + humic substances (HS), S + B + HS + ammonium sulfate (AS), S + B + HS + ammonium nitrate (AN). The results from the first experiment showed significant increase in N-tester values and aboveground biomass after the treatments with S enhanced with both mineral fertilizers compared to any other treatments. The content of N and S in plants was also higher after these treatments. This was confirmed by second experiment. The seed yield was highest after the same treatments. The result from both experiments proved, that reutilization of waste S can be an interesting option. The application of sole waste S is a viable possibility. However, the mixture of sulfur with AS and AN is a more optimal alternative. Such combination could lead to better N use efficiency due to the co-application of N and S and also presents an interesting compromise to an overall lower consumption of mineral fertilizers (especially N) while adding more sulfur to the soil, especially in mixture with AS. This treatment resulted in the highest seed yield and production of oil in comparison with any other treatment.