Where silage yields have been disappointing, consider overseeding as an alternative to a full plough and reseed, as this will boost future DM yields without the need to take a field out of use.
There are several options. The most hit-and-miss method is simply to rough up the fields with a harrow, then broadcast seed and roll it in. The fate of seed then depends on it landing on open soil with sufficient moisture to germinate.
A more reliable method is to use a harrow with a seed box – this will drag annual meadow grass and moss out of the bottom of leys, opening swards for seed. Alternatively, a slot-seeding drill will slice swards open with a disk and some have vibrating coulters which will create a mini seed-bed.
The best time to overseed is after second-cut silage and later in autumn, to avoid aggressive competitive growth from existing grass.
As for clover, oversowing will improve both nutritional quality and save on bagged nitrogen purchase. However, clover seed is tiny. So, to overcome sowing challenges, use a pelleted clover mixture in which size and weight is doubled. This improves sowing to the extent that clover can be sown using a spinner on the back of an ATV.
Extra grass and clover supplies can also be grown under young maize crops. When undersown now, a new ley will have established by autumn. This will provide a carpet on which forage harvesterand trailers can travel, reducing ground damage and potential winter run-off.
For farmers in the Entry Level Scheme, undersowing also earns 18 points/ha without having to harvest before 1 October. This longer harvest window allows maize cobs more time to reach maturity and optimum feed quality.
In Advanta’s undersown maize trials, current herbicides showed no significant residual activity against grass. Results show that once post-emergence herbicide has been applied, an undersown grass/clover ley can establish successfully and should not affect maize yields.