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 the Netherlands generally, rather than this case study specifically, this a duplicate of the article of the same title given in the »Overijssel, NL case study section.

1. Context

The area of arable land in the Netherlands amounts to 25% of the total land area or 47% of the agricultural used area (Source: Statistics Netherlands). History: From the end of eighties, nutrient policies have been implemented to decreases nitrogen and phosphorus losses to the environment (Van Grinsven et al., 2016). In 2006, the current manure policy was implemented in the Netherlands.  

2. Catch crop schemes in the Netherlands

1. Mandatory catch crops in Nitrate Directive

The growth of an unfertilized catch crops is mandatory since 2006 for silage maize on sandy and loess soils in the whole of the Netherlands, i.e. soils vulnerable for nitrate leaching to groundwater. The catch crop after maize has to be sown before 1 October and has to be kept on the field until at least 1 February (Source: Sixth Action Program of the Nitrates Directive of the Netherlands). The allowed catch crops are listed in the Fertilizer Act, and include English and Italian ryegrass, winter cereals, leaf radish and leaf cabbage. Approximately 65% of the silage maize land in the Netherlands is covered during winter by a crop (Fraters et al., 2016). This measure is controlled by field inspection. In addition, farmers have to keep a record of the catch crop seed that they bought. From 1 January 2021, a catch crop has also have to be sown after potato on sandy and loess soils in the southern part of the Netherlands before 31 October.

2. Ecological Focus Area (EFA) catch crops

Farmers with more than 15 ha arable land have to use 5% of the area of arable land as Ecological Focus Area (EFA) to get payment for CAP. They receive 30% direct payment (Pillar 1 in CAP) coupled to greening. The growth of catch crops is one of the elements that counts as EFA in the Netherlands. The catch crop has to be sown between 15 July and 15 October and has to stay for at least eight weeks on the field. The area of the mandatory catch crops on sandy and loess soils do not count in the EFA. In 2015, approximately 41% of the arable land was covered in the winter by catch crops, green manures, winter cereals or grassland (Fraters et al., 2016).

3. Farmers' current perceptions of motivations and challenges for implementing catch crops

Potentials

Farmers grow fertilized winter crops (green manures) as source of organic matter to improve soil quality. The amount of nitrogen that can be applied to these green manures has been reduced in 2019 to decrease risk of leaching (Sixth Action Program of the Nitrates Directive).

Barriers

There are doubts of the effectiveness of this measure to decrease nitrate leaching, because the nitrogen uptake of a catch crop sown in the second half October is small (less than 10 kg N per ha; Schröder et al., 1996).

Notes:

For full references to papers quoted in this article see

»References