NVZs – Mixed farms: Calculating the Whole Farm N Limit

“Even though it’s not producing or importing any highly-available nitrogen material, a general beef, sheep and arable farm will still need to do this calculation,” says Andersons‘ consultant Oliver Lee.

“This shouldn’t be as worrying as for a dairy unit – generally these farms are much less intense in terms of nitrogen produced and beef cattle and sheep are much lower producers than dairy cows, so the implications are not as great as for a dairy farm.”

• The calculation begins by working out the total nitrogen output of the livestock on the farm. The DEFRA booklets provide the information needed.
• First, establish the total N output from livestock manures each year.
• Divide this by the total farm area to give the Whole Farm N loading level.
• Compare this to the 170kg/ha limit. “As you can see, our example is way under the limit,” says Mr Lee.