Following the winter period, it is important to examine the condition of your grassland. After all, good sward quality is the foundation of good forage. What is the proportion of undesirable grass varieties in the sward? Does the grassland contain a high proportion of weeds? These factors can determine the yield of an entire year. The difference between desirable and undesirable grasses can easily amount to 100 FUM (feed unit milk)/kg of dry matter! 

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Proportion of desirable and undesirable grass varieties

If the grassland contains a significant proportion of poor quality, undesirable grass (20-40%) and weeds, we advise passing over the field once or twice with a harrow. Poor grass and weeds are more shallowly rooted than good, desirable grass and will be effectively uprooted by the harrow. The weeds can then decompose and will not be cut as part of the silage grass.

Harrowing is best done in dry weather conditions. The grass and weeds pulled from the soil will dry and decompose faster.

Mole hills

During cutting, the soil in the mole hills is dispersed through the grass. This adds extra crude ash to the silage and therefore reduces its feed value. Harrowing prevents this.


If you attach a seed drill to the harrow, new seed is overseeded at the same time. This will replace the undesirable grasses and weeds and boost the feed value of the grassland. And the forage quality too! Good forage means less concentrate.

Overseeding approximately 15 to 25 kg of grass seed can deliver a 10 – 15% higher yield per hectare. This increases the feed value and can save as much as €200 annually.

How to recognise desirable and undesirable grasses

Pull a handful of grass out of the soil and look at the base of the stems. If they are red, the grasses are good, desirable varieties. A white base usually indicates undesirable grasses such as annual meadow grass and rough-stalked meadow grass.

Read more about Grass Silage