ITALIAN RYEGRASS – RYEGRASS
Italian ryegrass, or annual ryegrass, is a high-yield forage grass that is particularly suited to cool, fertile plains and hills.
There are two botanical forms:
– an annual spring-seeding form (var. westerwoldicum)
– a biennial form sown at the end of summer, beginning of autumn (var. italicum)
Ryegrass varieties also differ in their number of chromosomes.
– DIPLOIDS (2n=14): plants with slender leaves and culms, and smaller seeds.
With early growth cycles, they are suitable for making hay as they have a lower water content.
– TETRAPLOIDS (4n=28): have twice the number of chromosomes as diploid varieties, with larger leaves and generally more developed organs, and more intense coloration. On the other hand, they contain more water than diploids (2-3%).
Ryegrass varieties are further subdivided into two groups:
– ALTERNATIVE = forming ears the year they are planted whether they are seeded in the autumn or spring;
– NON ALTERNATIVE = must go through the winter in order to come into ear.
Ryegrass forage can be eaten fresh or made into hay or silage. When using it fresh, seed mixes with legumes (e.g., Landsberger) appear to be preferable. Meanwhile for hay and silage, it is recommended that the crop is used on its own both for ease of machine harvesting and to limit losses during storage. When making silage, two different methods can be followed: either harvest late (after flowering) and directly ensile the grass, or harvest earlier and pre-dry in the field to make haylage. The first option results in higher yield, easier storage and lower costs, but the fodder is coarser and richer in fiber and lignin. Choosing one method over the other will depend on many factors, including the environment, geological attitude, the type of livestock reared, etc., so there is no single definite solution. In principle, however, it can be assumed that in dry environments, as well as conditions where using machinery is difficult (hills), late harvesting and direct ensiling is more suitable. Meanwhile, the second solution may be preferable for loose, well-watered ground on the plains where the rye-grass is followed by a summer crop and where intensive farming is typical, which requires high-energy forage.