Inspection of CAFP canal discharge


In a healthy farm system, agriculture works in harmony with the natural environment. This begins with healthy soil that stores water and nutrients and provides a stable base to support plant roots. In a sustainable system, soil is kept in balance. Crops are rotated through the fields to replace nutrients in the soil. Where there is livestock, animals graze the land, then waste from those animals is used to fertilize the soil. The idea is that as farmers take from the land they also give back.

Industrial farms disregard that need for balance. Land is used continuously and not given proper rest. Crops are not rotated in a way that replenishes the soil. Manure and chemical fertilizers are used to “feed” the soil, but through over-application these additives become a problem.

Animal Manure

Factory farms concentrate an unnatural number of animals in one place, which creates an unmanageable amount of waste. For example, a single hog excretes up to 17.5 pounds of manure and urine each day. Put 1,000 hogs together, and that’s six million pounds of waste each year. On a factory farm containing 35,000 hogs, over four million pounds of waste are produced each week, and over 200 million pounds each year.   1 Whereas on a sustainable farm animal waste can be a tool, in factory-farm amounts it becomes a major pollutant.

The creation and disposal of such enormous quantities of waste has a devastating effect on the air, water and soil surrounding factory farms. Unlike human waste, livestock manure is not processed for sanitation. On factory farms it is commonly mixed with water and held in pits (called “lagoons”), and then spread or sprayed on cropland. But the system often suffers from an excess of manure: the lagoons can leak or spill, for instance, or the manure is over-applied to fields, which can cause it to run off into surface waters.


Manure carries with it other substances that are used on industrial farms. These include antibiotics and artificial growth hormones, which contaminate waterways and affect the plants and animals that live in them.   2 Salt, a common component of manure from industrial dairies, can damage soil quality and contributes to erosion.   3

Nutrients and heavy metals present in animal feed are also excreted by livestock, and so end up being applied to cropland. These include zinc, copper, chromium, arsenic, cadmium and even lead.   4 In balanced amounts, some of these elements can be good for soil and promote plant growth. But as factory farms over-apply manure to fields, a significant quantity of nutrients builds up in the soil and can actually reduce the soil’s fertility.   2 This damage is difficult to reverse, and ultimately puts fertile cropland out of use.   5

Air and Water Pollution

Factory farms emit harmful gases and particles such as methane and hydrogen sulfide, which can contribute to global warming and harm the health of those living or working nearby. Air pollution results from the overuse of machinery, the mismanagement of manure, and the irresponsible feeding practices that characterize industrial farming.

Chemical fertilizers and pesticides have turned agriculture into a leading source of water pollution in the United States. Runoff from factory farms kills fish, degrades aquatic habitats and threatens drinking water supplies. Additionally, factory farms use tremendous amounts of water, which cuts into our precious supplies of water that are not contaminated.

What Is Soil?

It’s not just dirt! Soil is a mixture of minerals, air, water, and organic matter such as roots, decaying plant parts, fungi, earthworms, bacteria, and microorganisms. An acre of healthy topsoil can contain 900 pounds of earthworms, 2,400 pounds of fungi, 1,500 pounds of bacteria, 133 pounds of protozoa, and 890 pounds of arthropods and algae.   6

Feed Crops

Factory farms also harm American farmland through their consumption of massive quantities of feed crops. Consider this: The average cow eats roughly 30 pounds of food each day.   7 The beef industry raises more than 30 million cows each year.   8 Some of those cows feed themselves by grazing on pasture, but the vast majority are raised in feedlots, where they eat corn and soybeans. The result: American cropland is pushed hard to produce an extraordinary amount of grain.

In response to this demand, conventional crop producers have adopted intensive growing practices. These methods increase crop yields, but they also damage the soil and throw natural systems out of balance, primarily due to erosion and loss of fertility.

Crop farming is an ”extractive” process, meaning that as plants grow, they take nutrients from the soil and turn it into plant matter. When the plants are harvested, the nutrients leave the soil’s system. Sustainable practices replenish these nutrients, using compost, manure, or “green manures,” which are plants that naturally deposit nutrients in the soil. Instead of replenishing the soil, intensive practices use chemical fertilizers to supply only what is necessary to grow the next round of crops. Chemical fertilizers are not as effective as natural sources of fertility, and are known to cause long-term depletion of organic matter, soil compaction, and degradation of overall soil quality.   6 In 2005, American farmers used more than 22 million tons of chemical fertilizers.   9

Tilling is another aspect of farming that has gone out of balance in industrial practice. When land is plowed, old organic matter is turned under the soil in order to plant a new crop. However, when soil is bare it is most susceptible to erosion.   10 There are many ways to protect against this. Farmers can leave strips of land untilled, to act as a catch for water-borne erosion. Instead of plowing up and down hills, leaving furrows that carry wet soil straight downhill, they can plow with the contours, making furrows that act as tiny retaining walls. And they can grow cover crops in the off-season, whose plants anchor the soil with their roots.

In the drive to produce ever more grain, however, precautions like these are often not taken. Currently, the average rate of soil erosion on US cropland is seven tons per acre per year.   6 This is a serious problem, because erosion causes fertile farmland to lose nutrients and water retention ability. Because the first thing to go is precious topsoil, the soil removed by erosion contains about three times more nutrients and 1.5 to five times more organic matter than that which remains behind.   6 The National Sustainable Agriculture Information Service writes that erosion is the single greatest threat to soil productivity in the United States.   6

Know your Fertilizers

Natural fertilizer

Because they are composed entirely of organic matter such as manure and compost, these contain a wide range of nutrients and replenish the soil’s organic composition. USDA “Certified Organic”   produce can only be grown using natural fertilizers.
Synthetic or chemical fertilizer is composed primarily of nitrogen, phosphorus, and potassium; these petroleum-based soil additives lack the organic matter contained in natural fertilizers.


A nutrient-rich mixture of decaying organic matter (typically leaves and other plant parts) used as fertilizer for plants.

Sustainable Alternatives

By using farming techniques such as crop rotation, conservation tillage, raising animals on pasture and natural fertilization, sustainable farmers produce food without having a negative effect on the environment. Instead of harming soil, air and water, sustainable farms actually enhance and preserve the land so that future generations can continue to use it for food production.

What You Can Do

By supporting small, sustainable farms you can help reduce the impact of industrial farming and promote the use of environmentally friendly farming methods.

Did You Know?

For More Information

Reports and Articles


  1. Norberg-Hodge, H., Merrifield, T., & Gorelick, S. (2002). Bringing the food economy home: Local alternatives to global agribusiness. Bloomfield, CT: Kumarian Press, Inc.
  2. Environmental Protection Agency & U.S. Department of Agriculture. (2002). Animal feeding operations unified strategies. Retrieved August 15, 2012.
  3. Howarth, R. et al. (2000). Nutrient pollution of coastal rivers, bays, and seas. Issues in Ecology, Ecological Society of America, 7. Retrieved August 23, 2012.
  4. Organic
  5. Pennsylvania State University. (2006). Agronomy guide 2005-2006/Part 1, section 1: Soil management. Retrieved September 19, 2006.
  6. U.S. Department of Agriculture, Economic Research Service. (2006, Sept 25).  U.S. fertilizer use and price. [Online data set]. Retrieved August 17, 2012.
  7. U.S. Department of Agriculture, Economic Research Service. (2006, August 11). Statistics and Information: U.S. beef and cattle industry, 2002-2010. Retrieved September 19, 2006.
  8. Rasby, R. (2006, Agust 21). Estimating daily forage intake of cows. University of Nebraska Animal Science. Retrieved October 13, 2006.
  9. Sullivan, P. (2004). Sustainable soil management: Soil systems guide. National Sustainable Agriculture Information Service, National Center for Appropriate Technology.
  10. Food and Agriculture Organization, Livestock Information, Sector Analysis and Policy Branch, Animal Production and Health Division. (2002). Livestock policy brief 02: Pollution from industrialized livestock production. Retrieved August 17, 2012.
  11. Li, Y., McCrory, D. F., Powell J. M., Saam H., & Jackson-Smith, D. (2005) A survey of selected heavy metal concentrations in Wisconsin dairy feeds.  Journal of Dairy Science. 88(8), 2911-2922: Retrieved August 17, 2012.
  12. California Regional Water Quality Control Board, Santa Ana Region. (1990). Dairies and their relationship to water quality problems in the Chino basin. Santa Ana, CA: Schneider, J., Anderson, G., Holub, R., Litton, G., Nicklen, R., Stewart, G., and Turner, R. Retrieved August 16, 2012.
  13. Environmental Protection Agency. (2004). Risk assessment evaluation for concentrated animal feeding operations. Office of Research and Development, National Risk Management Research Laboratory. Cincinnati, OH. Retrieved August 16, 2012.
  14. Loehr, R. (1968). Pollution implications of animal wastes—A forward-oriented review. In Water Pollution Control Research Series. Office of Research and Monitoring, Environmental Protection Agency (p. 26).