Mineral additives to cattle slurry based on sulfur compounds improve the nitrogen (N) balance of grain maize during the grain filling period (GFP). This hypothesis was validated on the basis of a field experiment with maize conducted in three consecutive seasons (2017-2019) on soil low in available sulfur and calcium. A field experiment was conducted at Lipie (51°51'34" N, 17°5'5" E, Poland) on soil formed from sandy loam, classified as Albic Luvisols. The experiment incorporated two factors that comprised two forms of sulfur fermented with cattle slurry: elemental sulfur (S-0) and calcium sulfate dihydrate (Ca-S) applied in four doses of S: 0, 22.5, 45 and 90 kg ha-1. The dose of N applied in the cattle slurry was 133 kg ha^-1. The average grain yield (GY) after slurry application (control S) was 9.6, 10.1 and 8.6 t DW ha^-1 in 2017, 2018 and 2019, respectively. The increase in GY in response to S application was 0.75 t DW ha-1 (+10% compared to S control) in 2017 and 1.4 t DW ha^-1 (+16%) in 2019. In the latter season, GY depended on both N sources, i.e. on its remobilization from plant resources and uptake from soil. However, the driver of GY increase in response to the applied S was post-flowering N uptake. The study showed that the application of cattle slurry enriched with sulfur is an agronomic solution to increase the productivity of N in maize, especially in years with a deep drought as in 2019. For this reason, this treatment should be treated as preventive measure.