Mob grazing
Taking on an overgrown sparse spindly thin pasture that is very long because it has grown on poor depleted soil. What do you do?
You can either keep overseeding and throwing on bagged fertilisers, growing your grass in dirt not soil or you could try developing your soil health by the creation of a lovely self sustaining organic permaculture. There are lots of ways to do this and mob grazing is one of them ...
Mob grazing could become more popular in future as the government ramps up pressure on farmers to rebuild soil.
Mob grazing is when fields are given more time to rest and are not grazed as hard – it enhances soil health cheaply, without having to drastically alter systems.
The extended nature of mob grazing allows grass leys more time to recover. This promotes leafy growth, builds root structure and improves overall soil health – at the same time as boosting grassland productivity.
However, it does require intense management. So what do we need to know?
Tall growth
One of the main principles behind mob grazing is to let the plant grow much taller, with more biomass allowed to encourage root growth below ground.
If plants are quite small, then they will only have a small root, so you can’t start with that. Without the biomass, the plant thinks it does not need to root anymore, and so topping, although encouraging tillering, will not keep those very long root systems as it will cause the root to die back to the same height of the grass. This is why you must start with long grass with long roots.
How does mob grazing differ to rotational grazing?
Mob grazing is very similar to rotational grazing, but the key difference is that grassland is grazed with much higher stock numbers for a much much shorter amount of time. Or you graze a smaller patch relative to stock. (I sometimes think of it as rotational grazing at breakneck speed in tiny paddocks, alongside Benny Hill music and underwear clad chases, yes, I’m showing my age). Much trampled grass and manure is left to rot down and far from being wasted, actually is used to feed your soil. Fields are then rested for longer periods before animals return to them for everything to rot and grow or germinate again.
How does it work in practice?
Stock might be moved on a daily or twice-daily basis, so the system is more intensive than rotational grazing in terms of management.
Stock should be turned into fields when grass is knee-high and taken out when it’s ankle high in only some places.
The golden rule is for stock to:
1. graze one third
2. trample one third and
3. leave a third.
This places a lot more carbon into the upper layers of the soil to create a sponge of organic matter in the top layers quite quickly.
What plants should be grown?
Most that you see in a horse pasture anyway, minus the weed seed heads. A mix of grasses, legumes and herbs is recommended
Types of forage plants suitable for mob grazing
Grasses Legumes Herbs
Festulolium Red clover Chicory
Cocksfoot White clover Ribgrass
Ryegrasses Alsike clover Burnet
Timothy Bird’s foot trefoil Yarrow
M fescue. Yellow trefoil Sheeps parsley
Tall fescue Sainfoin
Lucerne Sweet clover
Pros
* Low cost
* Even grazing
* Organic manure
* Weed control
* Deeper-rooting grasses improve soil structure and subsequent drought and flood tolerance
Cons
* Management and labour required to move stock daily
* Set up of fencing and water supply
How do you know if your soil is not good and lacking in organic matter so that mob grazing might be useful?
Basically, just look at it, if it’s not nice and peaty or you can’t tell or need some reassurance, you can try the following test ... (chances are if too much hay has been taken off it year in year out, the soil is pretty depleted).
4 step guide to carrying out an easy soil test for organic matter
1. Collect a number of soil samples from across the same soil type and field.
2. Fill a clear glass jar with water. Using a sieve or mesh, hook this over the rim of the jar and place the soil in the top so that it is sat in the water.
3. Leave the soil for half an hour and the sample will be saturated. The condition of the soil and the water will roughly indicate the level of organic matter in the soil.
Cloudy water indicates the soil is not very stable, while healthy soil with the best glomalin – or glue – should remain clear. Typically, the darker the soil, the higher the carbon level. However, high levels of calcium carbonate can cloud the water.
4. For a further indication of soil health, leave the sample on a window overnight. If there is soil left in the mesh in the morning, this indicates good soil health. If there is no soil left in the mesh, then the soil is in poor health.
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