|Main authors:||Morten Graversgaard, Doan Nainggolan|
|Source document:||»Hasler, B. et al. (2021) Identification of cost-effective and coherent management models for drinking water protection in agriculture. FAIRWAY Project Deliverable 6.4R 55 pp|
The assessment of pesticide and nitrate abatement measures used for the protection of drinking water from both surface and groundwater sources is one of FAIRWAY's research themes. For details of the methodology used for the assessment, an in-depth analysis of catch crops (a measure often used for nitrate abatement), and the general conclusion drawn from this and other case studies see »Cost-effective and coherent management models for drinking water protection.
Note: Because this research relates to Denmark generally, rather than this case study specifically, this a duplicate of the article of the same title given in the »Aalborg, DK case study section.
|2. Catch crop schemes in Denmark|
|3. Farmers' current perceptions of motivations and challenges for implementing catch crops|
In Denmark, arable land accounts for as much as 64% of the land. Nutrient and especially nitrogen policies have been in place since the 1980s (Dalgaard et al. 2014). The catch crops requirements in Denmark have been introduced to fulfill the National Aquatic action plans, as well as the Nitrate directive and the WFD. From 1987 green fields has been required for 65% of the cultivated area, and the green field requirement could be covered by winter cereals, grass, maize, root beets, set aside, mulled straw or catch crops. This requirement terminated in 2004. Since 1999 it has been required that farmers shall establish catch crops at a defined catch crop basis area, and from 2005, after the green field requirement was ended, the requirement for catch crops was 6% or 10% of the crop area within rotation, except fields with grass, beet roots and potatoes. The requirement depended on the application of organic fertilizer level – above or under 80 kg N ha-1. The requirement was increased to 10% and 14%. From 2002 it has been required to account for an N effect from catch crops on 12 kg N ha-1 in the fertilizer account and calculation of norm. From 2005 this effect was increased to 17 and 25 kg N ha-1, the levels are for the two levels of organic fertilizer applied. From 2016 it was introduced that the farmers were allowed to substitute the catch crop requirement with 7 alternative N reduction measures: reduced quota/norm, intermediate crops, catch crops implemented at another farm, energy crops, separation and burning of animal slurry, early sowing of winter cereals or set aside (Mathiesen et al, 2019).
The estimated required catch crop area in order to fulfill these regulations and objectives was 145,000 hectares in 2017 and 120,000 hectares in 2018 and 130,000 hectares in 2020. A political agreement was made November 25th 2019, increasing the required catch crop area to 380,000 hectares
In 2019 there are five types of catch crops schemes, which can be combined. The most recent regulations are in set in force from August 1st, 2019. The two first of the requirements below are part of the fertilizer regulation. The five catch crops schemes are presented below.
1. Ecological Focus Area (EFA) catch crops
If the farmer has an area (fields under plough) larger than 15 ha (not required for organic producers), then 5 percent of the area have to be EFAs. Here catch crops are one out of many measures that farmers can use.
2. Mandatory catch crops
All farms above 10 ha are required to plant 10/15 % catch crops on their fields depending on how much organic fertilizer that are being applied to the fields. The mandatory catch crops may be replaced by other measures, such as buffer zones, energy crops, set-aside or the farmer can choose to lower her/his nitrogen norm instead of sowing catch crops. There is also the option to sow extra catch crops, to fulfil future mandatory catch crops requirements in later years. Mandatory catch crops must be followed by a spring crop. Only specific varieties of crops may be used for mandatory catch crops, while others are allowed for EFA crops, they may be mixed and then the same area of catch crops may count as both a mandatory catch crop and EFA area (Thorsøe et al. 2017).
3. Livestock catch crops
If the farmer are applying more than 30 kg N per ha from animal manure or other organic fertilizer (not organic farms). Then you can be obliged to implement livestock catch crops. The farmer can replace the catch crops with other measures, as described above for the mandatory catch crops. Livestock catch crop requirements are set in catchments for nitrate-sensitive habitat types in Natura 2000 areas, where there has been an increase in the amount of organic fertilizer applied, as well as in coastal catchments with requirements according to the river basin management plans, according to the WFD.
4. Voluntary targeted catch crops
As part of a new targeted N regulation, the farmer can voluntarily sow catch crops or implement other measures.
5. Mandatory targeted catch crops
If there is not established enough voluntary targeted catch crops to secure an efficient nitrogen reduction under the targeted N regulation, then a mandatory catch crop implementation can be required from farmers in catchments that have a reduction needs.
In newspapers and agricultural communications, it has been pointed out, that some of the schemes (the targeted catch crops) are more attractive than others, due to higher levels of compensation.
Also, agricultural advisors, are giving advice about the motivations for reducing nitrate discharge and that catch crops should be used where larger quantities of N are expected to be released in the fall. These may be where animal manure is applied or crops that leave easily marketable plant residues in the soil. Other motivational aspects are that catch crops can contribute positively to the amount of organic matter as the soil's carbon pool increases, and this has many positive effects on soil fertility.
The fact that the farmer can trade or replace the catch crop requirement under the mandatory rule with other measures is a flexibility for the farmer. Experiences so far do not indicate a large amount of trading.
Farm advisors are stating that many of the known catch crop species, can be vulnerable to pest and plant diseases, and extra weeds.
Farmers are complaining that catch crop establishment can be difficult if irrigation is not possible.
Advisory services are recommending focus on timing of sowing: The sowing season in the autumn is absolutely crucial to the effect of catch crops. The total nitrogen uptake decreases by 2 kg of nitrogen for each day the crops were sown after 10 August. By sowing September 1, the effect of catch- crops is limited and can be replaced by early sowing of winter seed, which is a measure farmers can switch to under the mandatory rule.
Most farmers are integrating catch crops in their production plans (“field plans”) and crop rotation, however this creates some challenges. Farmers are requesting more catch crop species/varieties. Also a request for catch crops that have a longer growing periods (over- winter).
For full references to papers quoted in this article see