REVIEW
Replacing a heap of trouble with a mountain of opportunities
One of the main reasons why a great civilization emerged and survived for thousands of years in China is that everyone valued“ brown gold”. David- Toews, a veterinarian and author of“ The origin of feces” points out that until relatively recent years China had the most intensive and sustainable agricultural system in the world. This was possible because almost all human excreta, 90 per cent, was returned to the soil as fertilizer.
Over in Japan, farmers left buckets out for travellers to make their contribution, and in the seventeenth century, before the city of Edo became Tokyo, boatloads of fresh vegetables were shipped back from the countryside in return for night soil. Excrement became so valuable that traders were able to demand money as well as food, and for apartment dwellers the rent went up if neighbours moved out. Stealing shit became a crime.
As the author of this informative book, due out in June, tells us, the fact that it is a bit impolite to use the word says a lot about our failure to think about how important shit is to our survival. As he remarks,“ there are things we don’ t talk about, even if we are sitting on a pile of it,” and with a neat turn of phrase he gives us an important message:“ How can we unleash the incredible power of excrement if we don’ t know shit?”
He certainly has a point, and my own great-great grandfather would have agreed with it. As in John B Keane’ s wonderful play“ The Field” two lush meadows here still stand out from the surroundings because he arranged for them to receive the night soil from the nineteenth century Swinford work-house. I sometimes think, not so much of the stinking cart-loads as they bumped and rattled out over the road, but of how much these poor unfortunates gave back to the land.
No doubt, if I were to head off to the nearest big hospital in Castlebar with the
same idea in mind, I would need a slurry tanker, and my unwelcome arrival would be treated as an emergency. Furthermore, the Environmental Protection Agency would come down on me like the proverbial ton of bricks, and rightly so. Not only would I be filling up my tanker with excessively watered-down excrement, but I would be picking up bugs galore, antibiotics and goodness knows what other powerful drugs. Dumping that back on the land, bordered by a stream that meanders back into town, would not, alas, be such a good idea.
This kind of situation, the author notes, has come about because we humans have become so good in solving one problem without considering the fact that we are creating another. This is the sort of linear thinking that has earned dam engineers, road builders, intensive farmers and others, such a bad name.
He makes a telling observation, familiar from his own experience as a vet. Farmers make intensive use of antibiotics, such as ivermectin, which as he remarked“ is regarded as something of a miracle” because it keeps the bad bugs at bay. However, one of the problems this creates at the other end of the cow is that the drugs also suppress the dung eaters. Thus, you might say, the shit is no longer worth shit.
By comparison, an animal in the wild will feed a host of followers. An elephant, we are informed, only digests about 40 per cent of the food it consumes. What comes out is a feast for dung-beetles and other assorted creatures, and from their point of view, it is the elephant’ s role to bring down the nutrients from high above so that they can go back to enrich the soil.
Not that the author is preaching to us like an eco-warrior. As a practicing vet he clearly has his feet on the ground, and he well aware of the fact that lots of pathogens and parasites depend on excrement to move from one host to the next. Contaminated water is a killer. About two million people a year die from diarrhoea, most of them children. One particular parasite, Toxoplasma gondii, inhabiting the gut of cats, has given rise to concern because it has managed to spread into some of the remotest parts of the world. This particular parasite can cause pregnant women to miscarry, and the inflammation it causes is suspected of contributing to depression. The explanation for its spread is simple enough. There are lots of cats, and no one is really bothered about where the smelly contents of the litter tray is dumped.
Before anyone is tempted to grab and strangle the family pet, bear in mind that cats are only a tiny part of the problem. Strangely enough, while everybody is concerned about the extinction of so many species, the global population of all animals has actually increased. Here’ s how the author puts this in perspective:
“ In 10,000 BCE there were about a million people on the planet. That’ s 55 million kilograms of human excrement scattered around the globe in small piles, slowly feeding the grass and fruit trees. In 1800, there were about a billion people on the planet, so about 55 billion kilograms. By 1900, we had a world human population around 1.6 billion, which would have been 88 billion kilograms of human shit.”
We now have more than 7 billion people living on Earth, and not alone has the population shot up, but more and more people are living in densely populated cities. Intensive farming means that more and more animals are being packed into smaller spaces.
“ I do not think we need an international scientific study to tell us that there is a whole lot more excrement in the world than ever before in history,” he writes, and as he explains, it is not so difficult to work out what the consequences of simply dumping all or most of this means. In the UK, David estimated that humans discard 135 tons of nitrogen and 58 tons of phosphorus a year. The output from cattle is even greater, 280,000 tons nitrogen, 50,000 tons phosphorus and 100,000 tons nitrogen. Then come the chicks, hidden away in big sheds, producing 40,000 tons of phosphorus.
Obviously, this is not the smartest way to use our resources, but as the author explains, the aspiration to get“ a chicken in every pot” goes back a long way. Even in what we might think of the bad old days, no one was happy to see so many people starve. Intensive farming
SCIENCE SPIN Issue 58 Page 31