What are we doing to our children?
According to a Sustainable Food Trust (SFT) article (https://sustainablefoodtrust.org/articles/the-hidden-cost-of-uk-food-soil-degradation/ ) we could be leaving them, our children, enough soil, globally, for just 60 harvests or, in the U.K. just another 100 harvests. A pretty frightening thought.
The article does, however, go on to say: “This doesn’t necessarily mean that all soils will be completely exhausted within that time, but that at the current rate, the productivity of many soils will have declined so much that farmers will be unable to produce enough food for the global population, regardless of how much fertiliser they apply or the type of seeds they sow.”
But this is hardly very comforting.
A Parliamentary Office of Science and Technology postnote recalls how organic matter is vital for the physical, chemical and biological functioning of soils, going on to say:
“Around 18% of the organic matter present in arable topsoils in 1980 had been lost by 1995. One of the reasons for this was that grasslands were ploughed for arable use. Some experts consider that the amount of organic matter in some soils may now be reaching such low levels that crop production may not be sustainable in the long term. As organic matter declines, so does the soil structure, so that the soil becomes more susceptible to physical erosion. Steps being taken to address loss of organic matter from soils include recycling farm manures, sewage sludge, and composted green wastes in soils. However, injudicious application of these organic materials may lead to diffuse water (nitrate and phosphate) pollution, and air pollution (odour and ammonia). The challenges in future are to maintain and where possible enhance soil organic matter while minimising the polluting effects of applying organic materials.
The SFT article also says: “The conversion of grassland to cropland inevitably results in a significant loss of organic matter, with carbon and nitrogen from the soil transferred to the atmosphere in the form of the greenhouse gases, carbon dioxide and nitrous oxide. Although clay soils are more resilient than lighter soils to the loss of organic matter, where the land is used for growing crops year after year and not periodically returned to grass, organic matter losses also result in loss of soil structure. This makes the soil more vulnerable to erosion, which becomes a particular problem if cropland is left bare over winter. Some 3 million tonnes of topsoil are lost in the UK each year. Globally, 24 billion tonnes are lost annually, 3.4 tonnes for every adult and child on the planet”.
Clearly there is a lot farmers must do to address this situation.
At the same time as this is happening we also have a situation whereby an estimated 3,415,000 tonnes of waste are disposed of in the U.K. food sector each year.
Much of this could be used for composting - the process of letting bacteria, fungi, worms or other organisms break down organic material to form the partially decayed organic matter called humus, which is a vital component of healthy topsoil.
And yet the amount of food waste sent for composting (including anaerobic digestion) in the U.K. in 2017 was just 386,000 tonnes.
In England, food waste collection amounts to about 10% of the waste being recycled. The Local Government Association’s paper on ‘Meeting EU recycling targets’, published in May 2015, stated that only about half of the councils in England offered food waste collection together with garden waste, and it also stressed that “given reducing local authority budgets it is unlikely that enough councils will either be able to maintain or add collection of food waste - unless it becomes more cost effective to do so”.
But note, in Scotland, local authorities are required to provide separate food waste collections in non-rural areas. And in Wales, there are mandatory local authority targets for recycling, re-using and composting household waste (including food waste). 99% of households were provided with separate food waste collection services in 2015. Indeed “In Wales, pretty much every single household can recycle food and they probably recycle twice as much food as England”
Of course, many households could have their own composters, and may do already. It is estimated that home composting already diverts more than 500,000 tonnes per annum of garden and kitchen waste from the municipal waste stream, thereby also avoiding the costs of waste collection and disposal. (see video below or at https://www.youtube.com/watch?list=PL5226D060BA971E27&v=KnkHDTkhick)