The advantage of clover is its nitrogen fixation properties. This nitrogen is released back into the soil, where it benefits the grass. White clover can fix 150 kg of nitrogen per hectare, red clover up to 350 kg. This saves between €220 and €510 in fertiliser per hectare.
The nitrogen is released back into the soil, where it benefits the grass. If you include clover in a grassland mixture, you can reduce the application of nitrogen. Despite a lower application of nitrogen, grass yields remain high. Clover also keeps grass growth constant, so that rust can’t get a hold and the crop remains palatable in the autumn. A further advantage of clover is that cows can absorb it better. Field trials have shown that cows yield 1 kg more milk on grass-clover rations compared to a pure grass ration.
Clover can tolerate nitrogen well. It’s a myth that clover disappears because of nitrogen, but adding extra nitrogen does stimulate grass growth. This makes the grass heavy, and crowds our clover. Clover can even disappear completely, because it needs light to grow properly. Using clover with grass is a good option for up to 250 kg of active nitrogen per hectare.
The acidity of soil has a major effect on clover. If soil is too acidic, clover will not develop properly and rapidly lose out, so take a soil sample before ploughing. You can then see exactly how much lime the plot needs to get the pH value to an ideal level. For sandy soil, this value is 5.2 to 5.5; for clayey soil, 6 to 6.5.
Grass with clover is more palatable than grass without clover, and clover helps prevent rust in grassland. This has been confirmed by the Product Board for Livestock Farming (Productschap van de Veehouderij - PV). Cows also yield more milk if they eat grass with clover. Tests by the PV show that rations with grass and clover yield about 1 litre more milk than grass rations without clover.
There are two options for overseeding clover in permanent grassland; the white clover mixture Quartet or the red clover mixture Duet. Click here for more information about Quartet and Duet. Do not sow clover mixtures too deeply; 0.5 to 1.0 cm is ideal.
Clover can be sown by reseeding or overseeding. The machines required are different. For reseeding, use a normal grass seeder. Note, however, that clover seed can be sown less deeply than grass seed. A grass-clover mixture may therefore be sown up to 2 cm deep, although 0.5 to 1.0 cm is best. Sow clover before 15 September.
You can use a torsion weeder with a combination seed drill to overseed. A Hunter can also be used. This machine ploughs strips in the grass in which the clover seed can be sown later.