Why Tall Grass Grazing is Important
Having just watched this fascinating and inspiring talk with Dr Christine Jones, I wanted to pen some thoughts on why tall grass grazing is important.
Influenced by people like Rob Havard and Christine Page, we’ve tried to let our grass grow as much as possible before grazing it, and try to take no more than 50% of it when grazing, and ideally more like 33%. From watching Christine Jones’ talk I now understand why these two factors are so important, and perhaps more important than the length of the grazing period for the paddock. I’m starting to think it’s better to graze tall grass for a week before moving, than graze short grass hard, with daily movements. This is because longer grass can penetrate deeper into the soil, accessing more and more minerals and trace elements — vital to plant, animal and human health as well as helping to improve water retention and reduce water run-off leading to flooding, soil erosion and eutrophication of water courses. The longer roots allow the grass to establish a better connection with the all-important network of arbuscular mycorrhizal fungi (AMFs). I’m learning that the art of growing good grass (and therefore healthy animals with healthy produce) is to develop and nurture the microbial community below the surface, and key to this is aiding the AMFs that play such a pivotal role. With short grass, you have shallow roots, and you don’t gain these exponential benefits. The aim is to have the cattle at least knee-deep in the grass when they go into it. This is the key to sequestering carbon — essential for healthy soil, and for mitigating climate change.
4 more interesting facts I learned from the talk:
— Grass with higher levels of minerals and trace elements will grow much faster than plants that are nutritionally depleted. And perhaps paradoxically, inorganic fertilisers don’t help as they have a negative impact on the mycorrhizal network.
— If you graze less than 50% of the grass length, then you don’t suffer any retardation to the roots. Beyond this and you start to damage the root structure.
— If you destroy the mycorrhizal network, the grass can’t access all the required nutrients it needs to grow properly, and therefore the animal will be nutritionally deficient, as will the produce itself.
— Diversity is a more effective tool for grass growth than inorganic fertilisers. Research in Germany showed that having at least 12 plants in a pasture would lead to a better rate of grass growth than the use of artificial nitrogen.
