Farmers cut nitrogen emissions

23/07/2001 10:00

Since the introduction of the obligatory bookkeeping system for minerals (Minas) in January of 1998 the use of nitrogen in fertilising has fallen sharply. In 1999 the amount of nitrogen put on the land by means of manure fell by 11% compared to 1997. In 2000 this was down 15% according to the preliminary figures.

There has been a policy on fertiliser use since 1984. Until 1998 its main aim was to cut the amount of phosphate in manure. The assumption was that the amount of nitrogen would fall along with the amount of phosphate.

The amount of phosphate in manure has been cut by a quarter since 1984. However, nitrogen did not "tag along". It wasn’t until Minas – since farmers have to account for the nitrogen surplus – that nitrogen emissions fell below the 1984 level.

In 1998 the amount of nitrogen in manure was lower than in 1997, but this was due to the extremely wet summer of 1998. The cows could not come out in the meadows as much and had to be fed roughage. It is only now that the cut in nitrogen turns out to be structural. Farmers are keeping fewer animals, and the nitrogen content in feed is down.

Mineral emissions by Dutch livestock

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In the areas with a manure surplus, the surpluses diminished. Apart from the year in which hog fever broke out, this has been for the first time since 1995. The manure surplus of pigs fell most. This is because farmers keep fewer pigs in the areas where hog fever broke out than before the outbreak. In other areas with manure surplus 20% more manure from pigs was transported out. About two thirds of the manure transported out of farm holdings to areas without a manure surplus comes from pigs.

Despite the lower nitrogen emissions, the water quality in ditches and groundwater did not really improve, because too much nitrogen gets into the water. In 1999 half the number of municipalities still faced manure nitrogen deposits over the legal maximum set in the European Nitrate guidelines that will take effect in 2003.

Martha van Eerdt