Approximately 10 % of crude ash in the dry matter is the limit for high forage quality.(10)
This corresponds to a soil content of approximately 1-2 % in the dry matter – but how can such small percentages be achieved?
Adequate protection of the sward
Adequate grassland care is the first step towards the production of high-quality forage with low soil content. Taking measures such as adapting intensity of use to a given site, levelling, rolling and re-seeding of appropriate varieties all help to ensure a high performance crop is produced which is able to form a thick sward. Complete coverage of the soil surface combined with a high percentage of grass in the mix facilitates a harvest with low soil content. Conversely, grassland with a light sward and many weeds increase the risk of forage contamination during harvest.
Combating pests such as moles and voles may also be necessary if they damage the grass stubble.
In order to protect the sward, soil compaction must also be avoided. It is therefore imperative that trafficking on the grassland only takes place in appropriate conditions when it is not too wet. The tyre size and pressure must also be properly set to combat compaction issues
Ensure the correct cutting height
The choice of the right cutting height is essential for harvest success with only small amounts of soil in the forage.
In general, forage should never be cut below the minimum height of 5-7 cm. Above this value, the cutting height has to be adapted to:
- The harvested crop,
There are numerous benefits to properly adapting the cutting height. The higher the stubble, the better the wilting of the cut grass, therefore improving the work quality of other machines in the harvest chain. This is because the cut grass is delivered as a layer on the stubble allowing it to sit above the soil surface. Moreover, a lower stubble height inhibits the regrowth of the grass and promotes the establishment of undesirable species.
Correct adjustment of harvest implements
All harvest implements (tedders, rakes, pick-ups of forage wagons /balers/forage harvesters etc.) must be properly adjusted to avoid the contact of the tines with the ground and therefore reduce as far as possible the incorporation of soil into the forage. The distance between the tines and the soil should be 3-4 cm minimum.
The driving speed should also be adapted to suit the field conditions (flat/undulating). This ensures that the implements can accurately follow the ground contours and prevent the tines from scratching the soil surface. Maximum driving speeds of approximately 5-7 km/h for tedding and 10-12 km/h for raking are recommended.
You can find the list of references below >
- Perennial vs. non-perennial grassland (arable feed crop production),
- Grass stubble conditions.