SFT Grazing Report - My Response

A comprehensive new report on the sustainability of grazing systems in the UK has just been published. I wholeheartedly support the notion that well managed livestock can be a force for regeneration of soil, pasture and landscapes at scale

While it is certainly true that the degradation of the Uplands for example is largely attributable to historic grazing (management) practices, it does not then follow that no grazing is the only (or best) response to this fact.

It is management that determines the health of land and ecosystems Management in this case refers to some form of sporadic pruning or defoliation of vegetationEither through cutting, burning or grazing. The latter being preferable as it is the only truly biological example of this process.

In this case the “health” (functionality) of an ecosystem is loosely being defined as plant species diversity, soil health and Net Primary Productivity (NPP). In this case the level of NPP (photosynthesis) determines the total amount of all non plant species that can exist in that ecosystem. So in general, higher NPP results are desirable, in ecological terms

Data now shows categorically that pruning significantly increases biomass production, over a given time (where other factors are equal)

Data from JENA experiment (where they’re comparing different mixtures of pasture plants) shows that going from one cut to two cuts more than doubles biomass production

The key conclusion here is that only through a pruning regime, is this level of productivity maintained. Furthermore in general, biological solutions are preferred to mechanical or chemical. In this case, mechanical would refer to cutting (mowing) and chemical refers to burning, fertiliser or herbicides.

Compared to mowing here, biological solutions are preferred because they don’t rely on external energy inputs and embodied energy to function. The biology derives its energy directly from the ecosystem itself and the productivity that the ecosystem generates. Although of course some of that energy will be released from the system either as heat, carbon dioxide or methane. But in this case, these emissions are part of a natural cycle and are not a net contribution to greenhouse gas concentrations.

In this case “biological solution” refers to herbivorous animals, and in our case, primarily grazing animals (livestock, deer etc). Only a sufficient number of animals can consume the required amount of biomass to be able to maintain this level of productivity. And consequently, as NPP increases, so does the carrying capacity of that ecosystem, in other words, the number of herbivorous animals it can support. In this case, it is essentially a virtuous circle more (sporadic) pruning means larger animal numbers supported and vice versa.

This brings us back to the initial assertion, that the it is true that historic livestock grazing is largely responsible for the loss of ecosystem health, it is not the animals themselves nor even the number that is the root cause of this degeneration, rather it is the method or “the how” (as it’s said in the report)
In other words, it’s the management of grazing animals (livestock). That is to say, it’s not too many animals in a given area, it’s animals spending too long over extended areas. Without going into the detail of this, essentially the take-home message here is that “cell/rotational grazing” or shepherding are what’s regarded here as best practise.

Again here the data shows significant increases in biomass production when comparing best practise crazy management against orthodox “set stocking”. Not only that, but we also see significant correlation between diversity and productivity, as indicated by the JENA experiment (above).

It’s for these reasons that I feel positive about the future of lowland and upland grazing as a means to deliver on ecosystem function, biodiversity restoration, improved soil, health and hydrology along with improved farming incomes. And as such I wholeheartedly support the key messages from this recent report. 

Link to report here