Trials have been carried out in 2007 and 2008 to evaluate the effects of application of soil additive UGmax in growing maize for grain and silage. The trials have been executed at Experimental station Swadzim of Poznań University of Life Sciences. Maize was grown after 6 years of monoculture. UGmax has been applied in spring, in dose of O,3 l ha -1. Application of soil additive UGmax in maize grown for grain, where there were many post harvest residues, caused significant statistic increase of yield, average increase amounted 7,1 dt ha-1 equal to 9,4% of yield harvested at control plot. Higher yield was correlated with higher grain moisture at harvest, in average 1,1% vs. control. In maize grown for silage it was observed increase of fresh matter of 55,9 dt ha-1 equal to 15,1% of yield harvested at control plot and in dry matter yield of 36,5 dt ha-1 and 32,3% respectively. Increase if fresh and dry mass yield was negatively correlated with quality of material for ensilage, i.e. tendency to lower corn ear content in fresh and dry matter.