Manure Doesn't Just Happen

Marty Strange
Senior Fellow, Center for Rural Affairs

Manure, as we know it, is a social product. It is part of the cycles of life involving domesticated animals whose location and movement (or lack of it), life span, diet, health, and hygiene practices are determined by and for people. The nutrients and other constituents in manure must flow, inexorably, through the cycles and balances of nature. They do not go to rest in some pollutant hereafter. They flow from one medium of the environment to another, from one place to another. Although what we as humans do matters a great deal about how fast and how benign this process is, we cannot put a plug in it and stop it. If manure is an environmental problem, it reflects us, our values, and the way we live. Popular bumper-sticker slogans aside, manure doesn't just happen. It is a social phenomenon.

And it is increasingly a controversial one. There is hardly a state where it does not lead the parade of concerns about livestock production. While many of the issues of concern are site-specific and local, nearly all are products of industrial systems. The now familiar aspects of these systems are: scale, concentration, integration, specialization, and uniformity. These terms, long a staple of urban-industrial discourse, are now routinely part of the vocabulary of agricultural analysis, especially animal agriculture.

In such systems, technologies are often system-dependent; that is, they interact so intensely that one part of the system is inherent in the other parts. One of the environmental implications of this system dependency is that "solutions" designed to mitigate adverse environmental impacts of one component of the system are likely to produce unintended (and maybe unanticipated) consequences through other parts of the system. Ecologists have long understood that some approaches to environmental management merely push problems from one medium of the biosphere to another. Generally, the tendency is to push problems from regulated to unregulated areas of the environment, from near-term to far-term consequences, from measurable to unmeasurable (or less measurable) phenomena, and from powerful to weak political constituencies. All of these shifts can be observed in the emerging livestock industry.

For example, the water-based waste management systems that are now conventionally part of the "up-scale" pork industry are part of a system of technologies that integrate genetic programming, nutrition, building engineering, herd health management, and other technologies into large-scale production, within the context of state and federal environmental regulation. Those regulations focus especially on clean water, and have lead to increasingly complex systems to keep manure-polluted water from contaminating ground and surface water. But the shift to water-based waste management also shifts the task of decomposition from aerobic to anaerobic bacteria, altering the composition and destination of manure constituents. Notably, the production of methane is increased from about 10% (under drylot condition) to as much as 90% of theoretical potential. Methane is a potent greenhouse gas implicated in global climate change. Capturing the methane as a fuel stock for heat or electricity alters the emission mixture, reducing methane but increasing carbon dioxide, a less potent but more persistent greenhouse gas.

In 1992, an estimated 28 percent of the U.S. hog herd was in facilities using anaerobic lagoons. These systems produced about three fourths of the methane emissions for U.S. swine (1.28 mil. tons) and about one third of the manure methane emissions from beef, dairy, and swine operations combined. This volume of methane was equal to about 13 percent of all carbon-dioxide-equivalent greenhouse gas emissions from all major U.S. agricultural sources. Since 1992, the percentage of hogs raised in facilities served with anaerobic lagoons has increased significantly. Despite the seriousness of this issue, almost all public discussion of the environmental impacts of these facilities has centered on water pollution and odor from relatively unstable gases.

It has become politically fashionable for defenders of industrial agriculture to ward off environmental regulation with the argument that regulation must be "science based." They want "proof'" - i.e., statistical reliability - that damage is being done to the environment by these systems, and they want similar proof that the proposed interventions will cure the problem at less cost to the economy than they impose. These arguments are, of course, as intellectually acceptable as the argument made by industrial agriculture's critics that farming must be "sustainable." Both are politically astute and reasonable arguments. But although both rely on scientific measures for credibility, neither is, in and of itself, a scientific argument.

This issue is about values, not science. And those values are revealed not in the science demanded by either side, but by the logic and the important ethical questions implied in the logic. While both sides freely use every logical argument they can muster, including any number of invalid arguments, the distinction I am referring to lies not in the validity of the specific arguments, but in the underlying type of logic that characterizes the final position.

The environmental argument that precautions must be taken rests essentially on deductive reasoning: If the premises are true, the conclusion must be as well. The premises are first principles of ecology, and the conclusions are irrefutable. For example: Matter is neither created nor destroyed. Nutrients are matter that can pollute. Therefore, nutrients that are concentrated in lagoons and removed by any means must be somewhere else and might be polluting. They must be stopped from doing so.

The industry argument rests instead on inductive reasoning, which relies on the claim that the premises provide probable grounds for its validity. For example: Microorganisms dangerous to human health and aquatic life prosper in streams loaded with nutrients. There are several potential sources of these nutrients. Properly constructed and managed lagoons will not leak nutrients into surface water. Therefore, nothing done to alter the design or management of lagoons is likely to contribute to restoration of these waters to health.

This reliance on probability, and the faith in our ability to manage within the tolerances of that probability, is firmly rooted in the free market experience of business people who are accustomed to operating as if there were no sure thing on earth. And indeed, they are very comfortable with the notion that things can be managed, though not by bureaucrats, through calculated risk taking.

Of course, industry seeks refuge in science and inductive reasoning whenever it wants to use uncertainty as a shield against having to accept responsibility for its own actions. The industry demands proof that leaking lagoons contribute to pollution not because they don't want to improve the environment, but because they don't want financial responsibility for the damage already done. Environmentalists sometimes retreat to the same position when asked to justify the "unintended" social consequences of the regulations they seek to impose.

I predict that industry's love affair with science, as the foundation for regulation, will be short-lived. Science brought us the environmental ethic. It will reinforce it.

But in the meantime, we will hear ever more about science-based management and regulation. And, we can expect to hear more about "managed" and "unmanaged" flows of nutrients and other potential pollutants as a polite way of distinguishing between an industry's economic successes and its environmental failures. It may be useful to elaborate on the distinctions involved in describing how human management affects nutrient flows. At least four categories of flows (some of which may overlap) are apparent now:

• Biologically Managed: Flows occurring within the ecological carrying capacity of the biosphere using only naturally occurring transformations (example: manure decomposition on well-managed pasture).

• Functionally Managed: Intended and controlled flows between pools or media to accomplish economic objectives without polluting (use of commercial fertilizer under best management practices).

• Dysfunctionally Managed: Flows that are either unintended or intended (but socially tolerated), from pools or media where the nutrients are not a pollutant to pools or media where they are a pollutant. These are often a consequence of biologically or functionally managed flows (nitrous oxide emissions from manufacture of fertilizer).

• Diverted: Intentional flows from one pool or media where nutrients are a socially proscribed pollutant or potential pollutant to another pool or media where they are a socially tolerated pollutant or potential pollutant (movement of nutrients or other pollutants from a lagoon to the atmosphere).

Many of the livestock waste management technologies under development today rely on diverted flows. They seek to pacify immediate environmental concerns, especially odor and drinking water pollution, at the expense of longer term concerns not (yet) the subject of regulation. Moreover, as science improves our understanding of secondary and tertiary effects of management practices designed to address immediate problems, it is likely that we will learn that many "best management practices" that produce flows now regarded as functionally managed have many dysfunctional and diversionary effects.

In the long run, the element that matters most environmentally may not be a nutrient, but carbon, the foundation of life itself. Only a tiny proportion of the global carbon budget is involved in the flows that sustain life. Ninety-nine percent is embedded in rock, in more or less stable form. Of the remaining one percent that circulates through chemical and biological processes, most is also in relatively stable form deep in the ocean. Less than a tenth of a percent (and falling fast) is stored in fossil fuels. About 0.03 percent is in the soil, mostly as organic matter. A tiny fraction, about 0.015 percent is in the atmosphere, and less than 0.01 percent of the global carbon is in living plants and animals. It is the circulation among these last three pools - the soil, the air, and living things - totally less than one-half of one percent of the earth's carbon, that is critical to life. Yet the largest environmental problem we face may well be the substantial reallocation of carbon from the soil, where it plays a crucial role in nutrient action, to the air, where at concentrated levels its critical role in the regulation of climate is altered.

Manure may be thought of as one of the delicate regulating materials through which carbon is allocated in ecologically balanced proportion between soil and atmosphere. Placed in water, its capacity to do so is placed in jeopardy. A manure management strategy that manages the flow of nutrients alone, without concerning the fate of carbon, is inadequate, even if it were to successfully avoid dysfunctional and diverted nutrient flows.

Agriculture is an industry intended to speed up the flows and transformations of nature, increasing outputs over time. It cycles more nutrients in less time by (for example) selecting for shoots, not roots, in plants, and breeding for concentrated feed conversion in animals. It concentrates more into less time and space than nature. It is at great risk of generating dysfunctional and diversionary flows that produce pollution.

That concentration is a problem independent of bigness, or "scale." Indeed, it is difficult to imagine a system that operates at a scale larger than nature itself, as for example, the global population of microorganisms have engaged in decomposition of manure. But nature is classically atomistic - many agents acting in balanced competition. Our economy is no longer that. If pollution is the concentration of any matter in a place that upsets the delicate flows and transformations essential to the renewal of life, then there is an analogous condition in society when too many resources, too much political power, too much control over the conduct of scientific inquiry, are vested in too few people. The challenge of industrial farming systems is not that they are big, alone, but that they concentrate everything from management capacity to manure in a few people and places.

The evidence is mountainous. It was always serious business when a country butcher ran a sloppy shop. But it is a public health crisis of vastly larger proportion when similar carelessness infests a beef processor capable of producing and distributing 400,000 pounds of hamburger a day to consumers in 30 states. The manure problem is that there are too many animals in too few places, and too much power among those who have them.

Concentration of animals, production, markets, and manure all have significant social and environmental implications that transcend the obvious impacts most likely to concern the public and policy makers concerned with immediate environmental problems. We do not yet fully understand the consequences.

Social ethics is the final arbiter of acceptable behavior. It is here that many modern environmentalists, themselves enamored of technical solutions, are uncomfortable with their own logic. There is no more virtue in technically correct micromanagement that ignores social consequences than there is in science-based regulations that scorn the idea that it is wrong to be a nuisance to neighbors, even if the law allows it. Both are about the failure (or refusal) to accept responsibility for action you take or prescribe others to take. Too many in our society seek the power to do whatever they have a mind to do, and concentration contributes toward that end.

We would do well to recall that three of the seven great sins Gandhi enumerated were: science without humanity; commerce without morality; knowledge without character. They apply to all of us, whether we think of ourselves as civic-minded environmentalists, or practical business people, or neither.

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