
Part 2 on Peak Phosphorus. (Again, the North African element makes this all the more pertinent than it was when I wrote this piece, due to the uprisings going on in that part of the world. Appears here exclusively.
For part one see here
Farming supplies of phosphorus come mostly from one part of the world - Morocco. They are also finite. A new Soil Association report suggests a peak in availability by 2033, as well as significant environmental concerns with current use in agriculture.
How could and should farming adapt to the finite nature of its inputs, in particular phosphorus? According to the Soil Association, there are three distinct action areas.
The first is changing how we farm. They point out that �different farming systems vary enormously in their reliance on mined phosphate. Organic farms are more resilient to the coming phosphorus rock �shock�, as it can only be used as a supplement to nutrient recycling (including crop rotations, green manures, and composting), and not as a replacement.�
They continue: �Organic crops generally have a lower fertiliser requirement than non-organic crops, with a greater capacity to scavenge for nutrients through denser and deeper root systems.�
They also suggest the need for a change in consumption patterns: �Eating less meat can reduce the demand for mined phosphate. This is because vegetable-based production is more efficient in its use of phosphorus than livestock production.�
However not all meat is the same: �Meat from livestock grazed on grassland that has not been fertilised with artificial fertilisers, will perform much better than meat from livestock grazed on fields that have been, or livestock fed on grain grown using artificial fertilisers.�
The third is novel but in terms of global nutrient cycles something of an unpalatable inevitability. Its changing how we deal with human excreta. The report recommends �a radical change in the way we treat human ex[c]reta and the need to abandon our current �flush-and-forget� toilet systems in favour of Ecological Sanitation.
�The report also calls for a change to EU organic regulations to allow the use of human sewage � rich in �natural� phosphate - on agricultural land to ensure phosphate levels are maintained. Globally only 10% of human waste is returned to agricultural soils. Urine alone contains more than 50% of the phosphorus excreted by humans.�
The use of these �Biosolids� (treated municipal/human sewage sludge) is already allowed in conventional agriculture.
I spoke to the report author Isobel Tomlinson (Soil Association) to explore these issues further.
Last one first: excreta. �in the longer term we recognise that there are problems with the current sanitation system: high water use, phosphorus water pollution, high energy-use as well as the continuing risk of contaminants - because industrial waste is added to the sewage system you get a risk from heavy metal contamination.�
Separating waste or, equally, nutrient, streams seems to be key: that's industrial from human, as mentioned, but also urine from solids:
�We think that we should move towards ecological sanitation which is a term that incorporates a range of different systems for solving these problems. We particularly mention urine-diverting systems as urine contains half of phosphorus excreted, is generally sterile and there are already examples of it being used in agriculture - for example Sweden. We would also like composting systems � the "humanure" approach - to be considered where appropriate.�
She also expands on the changing consumption and farming. Indeed, the two are connected, as what's produced is also consumed � either by animals or people.
According to Tomilson, along with changing production over to organic methods, what's needed is �An overall cut in dairy consumption, and dairy products to be sourced from grass-fed cows from extensive farming systems; More cereals and root crops and more seasonal fruit and vegetables; Less meat overall, but more grass-fed beef and lamb and less energy intensive, grain-fed and industrially-reared chickens and pigs.�
Ireland is well positioned to produce meat and milk extensively. We may, however, have to convince others to produce less and for us to be �The Producers� - i.e. the main suppliers for many parts of the world due to our extensive grazing. We may however, also have to make our grazing even more low input and grass-based - and do so not just for for phosphorus supply, but for many other environmental reasons too.
the Soil Association report is here