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Closed periods for fertilising in autumn in Germany

After harvest, the closed period for nitrogen fertilisers starts on arable land. Exceptions until 1 October and 1 December and the rules for grassland.

PhytAI editorial teamPublished 6 min read

Key points

  • Arable land: nitrogen fertilisers are closed from harvesting the last main crop until the end of 31 January.
  • Exception until 1 October: for catch crops, winter oilseed rape and field forage sown by 15 September, and for winter barley after a cereal preceding crop sown by 1 October, at most 30 kg ammonium nitrogen or 60 kg total nitrogen per hectare.
  • Exception until 1 December: for vegetables, strawberries and soft fruit.
  • Grassland and perennial field forage: closed from 1 November to 31 January; from 1 September to 1 November at most 80 kg total nitrogen per hectare from liquid organic fertilisers.
  • Solid manure, compost and phosphate: closed from 1 December to 15 January.
  • Shift: the competent authority can move start and end by up to four weeks but cannot shorten the period.

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In autumn many farms face the same question: may slurry, digestate or mineral fertiliser still be applied after harvest? The German Fertiliser Ordinance (DüV) answers with closed periods during which fertilisers containing nitrogen or phosphate must not be applied. The rules distinguish between arable land and grassland, name exceptions for certain crops and limit quantities. This article summarises what applies at federal level and what to watch for when recording autumn applications.

What counts as a nitrogen fertiliser

The closed periods concern fertilisers with a significant nitrogen content. According to the conditionality brochure of the Chamber of Agriculture of North Rhine-Westphalia, these are materials with more than 1.5 per cent total nitrogen in dry matter. This includes mineral nitrogen fertilisers as well as slurry, digestate, liquid manure and poultry manure. Solid manure from hoofed and cloven-hoofed animals and compost have their own, shorter closed period.

Arable land: closed period from harvest

Under section 6(8) DüV, nitrogen fertilisers must not be applied to arable land from the time the harvest of the last main crop is completed until the end of 31 January. The closed period therefore does not start on a fixed date but with harvest. Anyone who combines wheat on 20 August may in principle no longer apply nitrogen to that field from that day.

Exception until 1 October

Section 6(9) DüV allows fertilisation until the end of 1 October:

  • for catch crops, winter oilseed rape and field forage sown by the end of 15 September
  • for winter barley after a cereal preceding crop sown by the end of 1 October

In both cases the quantity is limited to a total of at most 30 kilograms of ammonium nitrogen or 60 kilograms of total nitrogen per hectare. The application must also be covered by the fertiliser requirement calculation. How that is structured is explained in Fertiliser requirement under the German DüV.

Exception until 1 December

Vegetables, strawberries and soft fruit may be fertilised until the end of 1 December. This mainly concerns vegetable farms with autumn and winter plantings.

Grassland and perennial field forage

On grassland, permanent grassland and arable land with perennial field forage sown by 15 May, the closed period runs from 1 November to the end of 31 January. In addition, from 1 September until the start of the closed period, at most 80 kilograms of total nitrogen per hectare may be applied there with liquid organic and organo-mineral fertilisers with a significant content of available or ammonium nitrogen.

Solid manure, compost and phosphate

Solid manure from hoofed or cloven-hoofed animals and compost must not be applied from 1 December to the end of 15 January. The same closed period applies to fertilisers with a significant phosphate content on all agricultural land.

Shift by the authority

The competent body can approve moving the start and end of the closed periods by up to four weeks. The length of the closed period stays the same. Such shifts are announced regionally, for example because of weather. Check the announcements of your chamber of agriculture or state authority.

Other rules in autumn

The closed periods are not the only limit. Nitrogen fertilisers must not be applied to flooded, waterlogged, frozen or snow-covered soils. Minimum distances apply next to water bodies, generally at least 4 metres from the top of the bank, at least 1 metre with a boundary spreading device; for conditionality, GAEC 4 additionally requires at least 3 metres. The limit of 170 kilograms of total nitrogen per hectare from organic fertilisers as a farm average applies throughout the year.

Nitrate vulnerable areas

Stricter rules, including for closed periods, applied in nitrate-polluted areas, the so-called red areas, under section 13a DüV and the federal state ordinances. In its judgment of 24 October 2025, the Federal Administrative Court declared parts of the Bavarian implementing ordinance to the DüV invalid, in particular the designation of areas. According to the brochure of the Chamber of Agriculture of North Rhine-Westphalia, the stricter state requirements in polluted areas are therefore not being checked under conditionality until further notice; new rules are expected during 2026. The chamber advises continuing to follow the previous rules in the interest of water protection. Check with the competent authority whether a state fertiliser ordinance applies in your federal state.

Common mistakes

  • slurry applied to stubble after combining without any following sowing
  • catch crop sown after 15 September and fertilised anyway
  • winter barley fertilised after oilseed rape instead of after a cereal
  • 60 kg total nitrogen respected but more than 30 kg ammonium nitrogen applied
  • closed period counted from a fixed date instead of from harvest
  • autumn application not recorded within 14 days

Recording in autumn

So that an autumn application can be traced during an inspection, the following details should be available together:

  1. Harvest date of the last main crop on the field
  2. Sowing date of the following crop or catch crop
  3. Preceding crop for winter barley
  4. Application with date, material, quantity, total nitrogen and ammonium or available nitrogen, recorded no later than 14 days after the application
  5. Nutrient content of the organic fertiliser from analysis or standard values

Closed periods in PhytAI

PhytAI links harvest, sowing and fertilisation per field in the same crop history. For a fertiliser application PhytAI records total nitrogen and phosphate as mandatory details, for organic fertilisers also available nitrogen, and checks it against the fertiliser requirement calculation. The 14-day deadline is shown for drafts. Harvest date, catch crop sowing and autumn fertilisation are thus side by side for an inspection. Assessing whether an exception applies and whether the authority has shifted the periods remains with the farm.

Frequently asked questions

May I apply slurry to a catch crop after cereals? Yes, until 1 October, if the catch crop was sown by 15 September, there is a fertiliser requirement and at most 30 kg ammonium nitrogen or 60 kg total nitrogen per hectare is applied.

Does the closed period also apply to compost? For compost, the closed period runs from 1 December to 15 January.

Does the closed period for maize start only after chopping? On arable land the closed period starts when the harvest of the last main crop is completed.

Sources

This article reflects the situation on the date shown, based on the sources named, and is not legal advice. Laws, approvals, official decisions and the guidance of the competent authorities prevail.

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