Half-a-century effects of a slow-release nitrogen fertilizer, ureaformaldehyde, on stand growth and soil processes in a Scots pine stand

•50-year effects of a slow-release N fertilizer, ureaformaldehyde were compared to a fast-release ammonium nitrate fertilizer in a Scots pine stand.•The tree growth-enhancing effect of ureaformaldehyde was slower but lasted much longer.•The humus layer was more N rich in ureaformaldehyde fertilized soil.