As a result, for hundreds of years the Asian farmer maintained an unbelievably productive agriculture. The food harvested per acre was at least five times the amount that American farmers were producing. Those yields exceed that of American agriculture even today, except where we practice intensive gardening. Indeed, for all practical purposes, a large part of China in 1900 was one huge, intensive, raised-bed garden. The Asian farmer had no choice; population densities were much higher than anything the United States had or has yet experienced. China either produced more food per acre or its people starved. And when they could no longer produce more even with the most rigorous natural fertility practices, the people did starve. My aunt was a missionary in China in the 1930s and she fascinated me with stories of Chinese pounding rocks to dust and eating the dust for food.
Over the last two centuries, cheap manufactured fertilizers and a seemingly unlimited acreage have allowed the United States to become the champion wastrel of the world. One can only imagine the famine and chaos that would result if we tried to continue that kind of extravagance for forty centuries. As sources of chemical fertilizers decline, either manure will once more become the pot of gold at the end of the rainbow or population levels will dramatically decline.
It is impossible to spread manure from a manure spreader with the same precision with which you can apply powdered or liquid fertilizer with a mechanical applicator.
So, how much is manure worth right now, when there is still a ready supply of chemical fertilizer available? You can Google reams of figures from agricultural colleges to answer this question, arrived at by multiplying the amount of plant nutrients in the manure times the current cost of these nutrients in manufactured fertilizers. These assessments are interesting, but not satisfactory. There are too many variables. Nitrogen, phosphorus, and potash levels in manure vary depending on the richness of the soil that provided the food the animals ate, while a sack of fertilizer will contain these nutrients in the amounts the label says it contains. The quality of the nutrients in manure and in chemical fertilizers may vary as well—a debate as old as the hills.
Even if everything else were equal, it would still be difficult, even for a computer, to compare the nutrient value of bulky manures with that of bags of fertilizer. A truck will hold by volume a certain weight of a certain fertilizer, while manure on a manure spreader, from one load to another, might vary not only in plant nutrient analysis but also in weight, depending on moisture and the ratio of dung to bedding in each load. In other words, it is impossible to spread manure from a manure spreader with the same precision with which you can apply powdered or liquid fertilizer with a mechanical applicator. These calculations become critical when determining the net value of hauling manure from an animal factory. Someone has to pay the freight, and the amount of plant nutrients in a truckload determines how far you can haul it profitably. And based on the amount of nutrients in both materials by weight, it is much cheaper to haul fertilizers than manure. Fuel cost becomes part of the equation too, of course.
Most important of all, agronomists have not yet been able to agree on a precise figure for the value of organic matter and humus that manure adds to the soil. I doubt if a precise figure is possible. It gladdens my heart to think that organic matter in the soil is so priceless that not even science can put a dollar value on it.
But it is fun and instructive to muse on the relative value of manure versus chemical fertilizer—a good thing to contemplate. For example, let us muse that Farmer A milks forty cows on an organic dairy farm. He has lots of manure as a free by-product of his dairying—the amount varies, of course, but you can roughly figure at least 15 tons of manure and bedding for each milk cow and half that for calves and replacement heifers. The manure, in fact, is essential to his operation because it would be very difficult (if not impossible) for him to make a profit organically without it. Since he gets a premium for his organic milk, his manure is worth even more than it would be for the dairy farmer not selling organic milk. Let us say that non-organic farmers in his neighborhood routinely apply fertilizer that costs—in summer 2009, as I write—about $80 per acre. Last year it could have cost twice that. For every acre Farmer A fertilizes with animal manure and green manure instead, he saves that much money right off the whirling blades of his manure spreader. If he manures 100 acres that way, he's saved $8,000, less the hauling and labor, before he puts a milker on his first cow.
Farmer B, however, grows 1,000 acres of corn and soybeans. His situation is vastly different when it comes to making decisions about fertilizer. He must buy all of his. Let us say he is not close enough to an animal factory to make hauling manure cost-effective, even if he could buy it cheaper than chemical fertilizer. He must buy the chemical stuff instead, at least for the 500 acres of corn. We'll assume that he doesn't put fertilizer on his soybeans, as many farmers do not. At $80 per acre, he has already spent $40,000 on his corn crop before he even climbs on his planter. You can readily see why my friend with 8,000 acres just might be getting interested in a cattle feedlot even if the beef side of the business only breaks even. With 4,000 acres of corn, his fertilizer bill is in the $320,000 range. And what if next year fertilizer prices go up again? The cow manure to replace that fertilizer begins to look like a very hot commodity indeed.
Then there is Farmer C, the garden farmer. He—or, just as likely, she—operates a vast spread of five acres upon which she produces much of the food for her family and produce she sells at a local farmers' market. She keeps a flock of 50 hens for eggs to eat and to sell, and she uses the manure and bedding to fertilize her gardens. She also has a composting toilet and uses her family's manure to fertilize the orchard and hardwood trees in her two-acre woodlot, from which she derives wood for home heating, bean poles, and fence posts, nuts, maple syrup, and an occasional meal of fried squirrel. What her manure is worth to her may be insignificant in terms of money, but what if 50 million other Americans did likewise?
Think of the excrement of 50 million people and 2.5 billion chickens helping to enrich soil rather than pollute water. Think of the food being produced without dependence on manufactured fertilizers or the need even for much fossil fuel. Think of all those people interacting with one another in their communities instead of running all over the world learning about nothing particular in any kind of deep, thoughtful way. Think of all those people feeling happy and important because they are involved in the meaningful work of feeding themselves and others, not overwhelmed by a paranoid fear that they are helpless before the dragons of a self-destructing economy. Think of something approaching an earthly paradise. If it gives you joy and contentment, who gives a shit what it's worth in money?
Adapted and reprinted from the book Holy Shit: Managing Manure to Save Mankind by permission of Chelsea Green Publishing.