Warm weather and good soil moisture has given us a flying start to spring. Legumes such as clover and Lucerne have woken up and started fixing nitrogen again which will soon start feeding the grasses. While autumn and winter are all about ‘how much feed can I grow?’ the goal in spring is ‘how long can I maintain feed quality?’
So how do we do this? In simple terms it’s about keeping the grasses within the ‘optimum growing window’ (3-12cm). Through autumn and winter we focus on managing to the lower threshold, trying not to graze below the 3cm mark to allow the plant to keep photosynthesising and maximise its light capture. But in spring things can get away from us pretty quick, grasses start to outgrow livestock consumption and plants want to run to head. With the warm weather over the weekend I noticed weeds such as silver grass putting up seed heads already, once plants start going to head digestibility will drop and so will feed quality (ME/kg DM).
Ryegrass and phalaris will be a while off going to head but if allowed to grow too tall feed quality can drop and production will slow down due to shading of the lower leaves. The key to managing to the upper threshold of 12cm and maintaining feed quality is to rotate your lawn mowers (livestock) often.
This can be hard for some to get their head around as it may require moving mobs to the next paddock before you think they have finished. Rather than thinking I will move the mob when they have eaten the paddock down to 3cm, which is what we would be doing in autumn, in spring we need to move the mob when the paddock they are going into has reached the 12-15cm point, to try and stop it from running to head or going rank.
Shorter more frequent grazing is better for the plant than longer harder grazing, the more residual feed left in the paddock the quicker the plant will recover, and if we find we can’t rotate quick enough to keep pastures under this threshold we can consider dropping a paddock out of the rotation for hay or silage. Other strategies to consider are creating larger mobs and/or smaller paddocks, this allows us to graze down paddocks quicker and more uniformly and keep the pressure on the grasses.
Whilst managing to this upper threshold can delay seed set in plants eventually the season will catch up and pasture quality will taper off, at which point we can start thinking about feeding strategies heading into summer. So the key message is that spring is all about maintaining feed quality for as long as possible and one of the best ways of doing this is to implement some sort of rotational grazing, manage to that upper threshold and keep your plants and livestock growing at their optimum.
Ashley Paech, Farming Systems Project Officer
- Posted by Holbrook Landcare Admin
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