A Simple and Effective Method
A very good way to improve old or damaged leys without re-seeding is to over-seed with ryegrass or clover mixtures. The main advantages are that there is not much interruption to the use of the field and yields can be increased at minimal expense.

The seed can be broadcast or drilled, but beware of sowing too deep. If broadcast, the seed should be rolled in or stock turned onto the area for a short time.

Timing is the key to success. Seeds should be sown after cutting or hard grazing. The sward should be reasonably open in the bottom and there must be sufficient moisture available. A light grazing is beneficial 5 weeks after sowing to remove growth and allow the new seeds to establish.

Tetraploid varieties of ryegrass are recommended as they have a larger seed and are capable of strong, competitive growth. They are also considered to be more resistant to drought than diploid grasses. This is most important for successful results.

Why Improve Pasture?
It has long been an established fact that response to nitrogen from “weed grasses” is much less than for preferred species such as ryegrass. It is also well known that with the passage of time weed grasses invade the sward so that after, say, 5 years the sown grasses amount to only about 50% of the sward.

As an example, a field with 50% weed grasses such as creeping bent, Yorkshire fog and rough stalked meadow grass will at best only have about half the response to nitrogen obtainable from a new ley.

Much of the forage obtained from permanent swards is produced from Agrostis, Holcus, Poa and Festuca rubra, all being inferior in potential to perennial ryegrass in yield, length of productive season, palatability and nutritive value (ref. Hubbard, Grasses).

These inferior species may get by in a “normal” season, but in dry summers their performance is very poor compared with preferred species.