Proteins of Twente's soils

Together with a number of dairy farmers in Twente, we are looking at the possibilities of increasing the amount of protein from the farms’ own soil in order to make it easier to meet the 65% guideline. Most dairy farmers in Twente are growing their roughage crops on sandy soil that is sensitive to drought, which means that yields are often lower than in other regions. Because grassland yields are lagging behind, the total protein yield is often insufficient to meet the guideline of 65% proteins from own soil.

This project involves six livestock farms for which a farm analysis has been performed and, based on this analysis, small practical trials are being carried out in cooperation with the respective farmers. These trials have various themes, such as maintaining the organic matter content of the soil, use of soil moisture sensors, incorporation of alternative roughage crops (e.g. broad beans, herbaceous grassland) or summer indoor feeding to reduce grassland losses.

The project is subdivided into three parts:

  1. Outlining the production, supply and utilisation of proteins at the six participating farms, in comparison with those at other farms in the Netherlands. For this purpose, we use the Annual Nutrient Cycling Assessments from the 2018–2020 period.
  2. Alternative plant species: looking at adaptation opportunities for the cropping plan and incorporating alternative crops such as herbs in grassland or broad beans in cornfields.
  3. Managing grassland more efficiently: focus on grass yield (dry matter and protein) per hectare, reduce losses from harvesting, ensiling and feeding.

Over the course of this project, effects of measures will reveal themselves and suitable tools will become clear.

The ultimate goal is to increase protein self-sufficiency, while maintaining animal and farm production levels and avoiding any negative impacts on other sustainability aspects such as CO2 and NH3 emissions.

Practical aspects

The project started in 2020 and will be completed by the end of 2021. In the first year, a start was made with the first trial fields. Broad beans were sown in-between the corn and, at a number of farms, in addition to grass, pasture mixtures containing herbs and/or clover were sown into grassland. At one farm, a switch was made to a combination of pasture grazing and summer indoor feeding. In 2021, the focus will first be on increasing soil organic matter content by adding clay, compost or slurry, in various ways. During the growing season, the different types of grasslands will be monitored to determine yields, feed value and botanical composition. By the end of 2021, the results from the various trials will be available and shared in practice.


Two interviews with Els Uijterlinde of Erve Mentink about this project appeared, one on a local radio station, the other in a Twente newspaper.

Cooperation and financing

The project is carried out by the Louis Bolk Institute in collaboration with Erve Mentink and six dairy farmers from north-eastern Twente. Financially, the project has been made possible by the Province of Overijssel.