Use of inorganic and organic fertilisers in agriculture 2013

In agriculture, fertiliser recourses are of great importance for economy, agronomy and environmental impact. The previous survey on storage and use of manure in Norway was conducted in 2000. The agricultural authorities therefore need updated knowledge, especially in order to assess efforts under the Gothenburg Protocol, and for drawing up a new fertiliser regulation. In addition, Statistics Norway and The Norwegian Environment Agency clearly see the need for better data as input to air emission accounts and for developing regionalised nutrient balances for the agriculture.

Statistics Norway has in 2013 accomplished a sample survey in order to examine the use of mineral fertiliser and manure in meadows for mowing and pastures, infield pastureland, other green fodder crops, potatoes, onions, cauliflower/broccoli, carrot, barley, oats, spring wheat, winter wheat and oil-seeds. In total, the crops included in the survey covered 94 per cent of the agricultural area in use. Further, the survey also examined animal housing, manure storage and manure spreading practices.

A sample of 4 900 agricultural holdings were drawn from a basic population of 37 700 holdings with at least 5.0 calculated animal manure units and/or at least 5 hectares agricultural area in use. The survey was voluntary, and 64 per cent of the holdings replied.

In 2013, fertilisers were spread at least once on 0.83 million hectares, or 90 per cent of the total agricultural area in use. Mineral fertilisers were used on 82 per cent of the agricultural area, while manure was used on 41 per cent of the area. In total, it was estimated that 124 780 tonnes nitrogen (total-N), 15 200 tonnes phosphorus and 72 040 tonnes potassium were spread on agricultural land in Norway in 2013.

Measured by area coverage, meadows for mowing and pastures are the main crop in Norway. A total of 70 550 tonnes nitrogen and 7 890 tonnes phosphorus were supplied on established meadows. In other words, 56 per cent of all nitrogen and 52 per cent of all phosphorus used in agriculture were used on established meadows. On average, 1.77 kg nitrogen and 0.20 kg phosphorus were supplied per hectare fertilised meadow. Infield pasturelands are moderately fertilised, corresponding to 0.94 kg nitrogen and 0.11 kg phosphorus per hectare.

The main part of the manure spread on established meadows was spread with blade spreader (57 per cent). Ammonia emissions would be significantly reduced if manure is spread by using band spreader or direct ground injection. The proportion of manure spread by using band spreader and direct ground injection has raised from 7 per cent in 2000 to 19 per cent in 2013.

Open fields comprise area that yearly are soil prepared and sown. More or less all the area of open fields was supplied with fertilisers. Mineral fertilisers were used on 93 per cent of the open field area, while manure was used on 30 per cent. In 2013, a total of 45 740 tonnes of nitrogen was used on open fields. By average, supply of nitrogen per hectare in cereals varied from 1.54 kg in winter wheat to 1.13 kg in oats.

Time elapsing from spreading of manure to when it is worked into the soil is an important factor for leakage of ammonia and laughing gas. The results from the survey show that manure was worked into the soil from 4 to 12 hours after spreading for 56 per cent of the open field area. Manure on 28 per cent of the open field area was worked into the soil within 4 hours. The corresponding part in year 2000 was 16 per cent.

Storage of manure from cattle, pigs, sheep, goats, horses and poultry are covered by the survey. Storage of manure from cattle forms the main part of all stored manure and accounted for 60 030 tonnes of nitrogen (total-N) in 2013. The manure from diary cows is either stored in cellar for slurry (75 per cent), or in outdoor manure pit for slurry (23 per cent). A larger extent of the manure from beef cows is stored as solid dung; with 12 per cent outdoor storage directly on the ground, 12 per cent indoor built up and 4 per cent outdoor built up.

Storage of pig manure in outdoor manure pit for slurry has become more common since year 2000, when 13 per cent of the manure from the main production “pigs” where stored in manure pit for slurry. In 2013, 30 per cent of the pig manure was stored in outdoor manure pit for slurry and 63 per cent in manure cellar for slurry. Use of cover on outdoor manure pit will contribute to less air emissions, as well as less odour nuisance. Results from the survey shows that use of cover is much more common for storage of pig manure than it is for cattle manure. While 36 per cent of stored pig manure in outdoor pit was covered, the corresponding part for cattle manure was 26 per cent. Use of cover is especially used in the region Rogaland.

The major part of the manure from laying hens is stored as solid dung in manure cellar/house (55 per cent), while the greater part of manure from poultry for slaughter is stored outdoor directly on the ground (83 per cent). Almost two third part of the manure from poultry for slaughter stored outdoor directly on the ground was stored without roof or other cover.