The report, entitled 'A rock and a hard place: peak phosphorous and the threat to our food security', found that “the supply of phosphorous from mined phosphate rock could 'peak' as soon as 2033, after which this non-renewable resource will become increasingly scarce and expensive”.
Composting experts have pointed out that compost, particularly that produced using green and food waste, is an excellent source of phosphorous and is already used by many farmers across the UK.
Brian Chambers, of environmental consultancy ADAS, said that the loss of mined phosphorous was likely to lead to an increase in prices for compost. He commented: “As fertiliser prices get higher composters will no doubt be able to charge more for their product.”
Currently a lot of compost that goes to agriculture is given away for free, or purchased at a very low cost by farmers. Mr Chambers explained that, although prices to agriculture were likely to increase, they would never reach the levels commanded by mined fertilisers.
This is due to the fact that compost is “bulky” and the associated transport and spreading costs will always be higher than those for artificial fertilisers, he explained.
Jeremy Jacobs, managing director of the Association for Organics Recycling, commented: “It is known that both phosphorous and potash are significant elements in compost which is why it is a useful soil amendment. Compost is an extremely valuable replacement and it should be promoted more.”
The report says that a lack of phosphorous to return to the soil could lead to food insecurity. It recommends that human waste should be used as a fertiliser instead of being wasted – a process that is currently banned under EU law.
It also praises theway organic farmers use compost to nourish the soil. The report states: “Organic farming systems already make use of many practices to reduce the need for mineral phosphate, including managing nutrient loss; using farmyard manure, crop residues and green waste composts as fertilisers; increasing the availability of phosphorus to plants by encouraging microorganisms and mycorrizal funghi; and using crops with high uptake efficiency.”
Compost is already widely acknowledged in the farming community as a way of nourishing the soil. Two years ago, when prices for nitrogen-based fertilisers rocketed, many farmers turned to compost to reduce their costs (see letsrecycle.com story).
Mr Chambers said: “Farmers like using compost if it is of a good quality and low in plastic. It is a good replacement for expensive fertiliser and it is also the right thing to do.”
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