Plant-based fertilisers & cover-crop strategies on heavy clay soils (Netherlands)

Farm sites: 

• Ebelsheerd (112 ha) heavy clay soils, conventional crops: winter wheat, barley, rapeseed, onions, sugarbeet, lucerne; organic crops: spring wheat, pumpkins, string beans. 
• Kollumerwaard: reclaimed clay soils, seed potatoes, sugarbeet, wheat, barley, grass-clover mixtures.

To test more natural approaches to crop nutrient management in three contrasting farming systems (organic, conventional, regenerative arable) in the Netherlands, focusing on plant-based fertilisers, cover crops, grass-clover mixtures and improved soil health. 

Dutch cropping region with heavy clay soils and seed-potato focus; issues include fertiliser supply uncertainty and soil health challenges in both conventional and organic systems. 

Part of the trans4num project funded by the European Union. 

Plant-based fertilisers and cover-crop strategies show promise in maintaining productivity, improving soil biological diversity and organic matter, reducing dependency on mineral fertilisers. 

• Cover crops in rotation with seed potatoes: research on optimal destruction timing to release nutrients. 
• Grass-clover mixtures in rotation with organic winter wheat: alternatives where manure availability is limited.
• Lucerne and grass-clover pellets (biofertiliser) for winter wheat: testing the impact of plant-based fertilisers vs mineral fertilisers on soil nutrient status and yield/quality. 

The diverse farming systems (organic, conventional, regenerative) and soil types provide transferable insights for similar intensive arable regions in Northern Europe looking for plant-based fertiliser and cover-crop solutions. 

Year 2 results show that plant-based fertilisers improved soil biological diversity and organic matter. Optimisation of timing and application rates is essential (NDICEA model used) for balancing nutrient supply and crop uptake.

Stichting Proefboerderijen Noordelijke Akkerbouw, Wageningen University

1. Stichting Proefboerderijen Noordelijke Akkerbouw

   Henk Westerhof

   westerhof@spna.nl

2. Wageningen University

   Paula Harkes

   paula.harkes@wur.nl

In the Netherlands, the site comprises two experimental farms: SPNA Ebelsheerd (112 ha heavy clay soils, both organic & conventional) and SPNA Kollumerwaard (reclaimed clay soils, seed potato region). The project is testing more natural crop-nutrient management through cover crops in rotation with seed potatoes, grass-clover mixtures, and lucerne/grass-clover pellets as biofertiliser alternatives to mineral fertilisers. Soil and crop data, microbial activity, and nutrient cycling are being collected.