Part three of a four-part series looking at the value of legumes in dryland farming systems. This week, we ask: How early is too early to graze lucerne?
Where, once, farmers used to wait until a lucerne crop had flowered before harvesting it, now scientists at Lincoln University are pushing the boundaries to see how early the forage can be grazed in late winter and early spring.
This year, Dr Alistair Black ran hoggets onto trial blocks of lucerne at Ashley Dene on 17 August. The crop, which had been spelled since May, was only 5cm high (1100kgDM/ha), but had started to grow.
The animals were allocated 2kgDM/head/day and shifted around the blocks on a six-day rotation. Alistair says that, at 5cm high, 84% of the lucerne was leaf and petiole and the rest was stem – so it was nice, leafy lucerne.
The quality of the feed was reflected in animal growth rates. The hoggets gained an average of 300gms/day between August and October.
The lucerne continued to grow, showing no ill-effect from this early grazing. However, it will be spelled in autumn to recharge its root reserves.