Nitrogen balances and yields of spring cereals as affected by nitrogen fertilization in northern conditions: A meta-analysis

► The developed models can be used to construct a tool for optimizing N management. ► N balances increased more steeply in moderately than in slightly acidic soils. ► Nopt was strongly governed by the control yield without added N. ► On poorly responsive fields N inputs can be reduced by 20-75 kg ha−1 without economic loss. ► Such improved practices could reduce N balances by 10-40 kg ha−1 year−1.