- lucerne (alfalfa), sainfoin (Onobrychis viciaefolia)
.
Sainfoin plants grow upright and make good hay, but only one cut per year is taken (at
the half to full bloom stage). Higher moisture content than lucerne, but cures better than
the clovers. Normally grown alone, it competes poorly with aggressive grasses.
Cutting Hay
Plants that have been cut before flowering are normally more nutritious and digestible
than more mature plants. However the yield of dry matter increases as the plant matures,
so the decision on the best time for cutting a hay crop is always a compromise between
yield and quality.
For most hay crops the most appropriate time is at flowering. Lucerne in particular
should be cut early in the season, as soon as the first flowers appear, as at that time the
protein content falls rapidly and the cellulose content increases rapidly.
Curing Hay
The quality of the hay produced is largely determined by the curing process, the
objective of which is to rapidly reduce the plant moisture content from about 60–75% to
about 25–30%.
After cutting, the plant material is left in the swath or swathe in the field until it has
wilted due to exposure to wind and sun. It is then turned over and concentrated into
narrower bands of plant material known as windrows. This reduces the area of cut plant
material (forage) which is exposed to sun and rain but still allows air to circulate which
further reduces the plants’ moisture content. In mechanised farming the windrow also
assists hay baling operations.
Losses During Haymaking
Even under ideal conditions about 10–15% of plant nutrients are lost, and the protein
content also often falls, by 30% or so. These losses, and other losses described below,
are caused by a number of factors:
- Biological factors—sugars and starches are reduced as the plants slowly die after
they have been cut. - Light and heat—the digestibility and palatability of hay is reduced by prolonged
exposure to sun, especially when the hay is dry. - Rain—any hay which is in contact with the soil may rot; also soluble nutrients are
leached, and the hay becomes discoloured and unpalatable. - Mechanical—if the plants are cut too high up the stem, potential hay is left behind
in the field (known as stubble). Secondly, because the leaves dry out more quickly
than the stems many of the leaves are lost when the plants are being turned and
dried. - Storage—if hay is stored at a moisture content above about 30%, heat can build up
which causes losses due to fermentation, heating and moulds. In severe cases the
73
Perennial legumes -
Cereal/legume mixtures- vetches and oats. This usually gives poor quality hay
due to the unequal rate of drying of the two species