One of the arguments used by native plant advocates to defend the use of pesticides to eradicate non-native plants and trees is that this use is trivial in comparison to the volume of pesticides used by agriculture. It’s not an argument that makes sense to us. In fact, the opposite seems a stronger argument. In other words, if it is necessary to use pesticides to produce our food, all the more reason to avoid the use of pesticides for other purposes, because the harm done by pesticides is cumulative. Humans and other animals accumulate pesticides and other toxic substances in our bodies throughout our lifetimes so the fewer sources of toxic contamination, the better.
However, as we learn more about how pesticides are used by agriculture and how harmful pesticides are to us and other animals, the more we question the underlying premise. That is, we wonder if it really is necessary to use pesticides to produce our food. We have researched this question and we are reporting to our readers a brief history of pesticide use by agriculture, the consequences of this use, and finally, the growing evidence that present levels of pesticide use by agriculture isn’t necessary or justified.
The history of pesticide use by agriculture
The use of synthetic pesticides by agriculture began after World War II as a result of the development of new chemicals and the industry that produced them during the war. Prior to WW II, farmers generally purchased raw chemicals to formulate primitive pesticides because ready-to-use pesticides were not available. Here are some of the statistical trends that describe the use of pesticides by agriculture: (1)
- Three-fourths of all pesticide use in the U.S. is by agriculture.
- Pesticide use has been consistent at 2.6 to 2.7 pounds per acre of cropland per year for the past 25 years.
- The volume of synthetic herbicide use has increased steadily since 1945, but the volume of insecticide use has declined after the 1980s as new low-dose products have been developed.
- Fruits/nuts lead all other crops in terms of pesticide applications, with about 45 pounds of active ingredient per acre grown. Vegetables receive about half that rate, but the rate nearly doubled from 13.4 to 23.7 pounds per acre from 1988-89 to 1996-97.
The expenditures for pesticides by agriculture are another way to understand the increased use of pesticides and their importance to both the agricultural industry and the chemical industry: Farm expenditures on pesticides have increased from $296 million in 1929-31 to about $8.5 billion in 1995-97 in constant dollars. These are the factors that account for increased expenditures over seven decades: (1)
- The amount of active ingredient in pesticides usage increased during that period three fold (from 230 to 782 million pounds).
- The replacement of low cost pesticides such as sulfur and petroleum by more expensive formulated pesticides.
- From 1974-76 to 1995-97, the average expenditure per pound of active ingredient nearly doubled.
- The average expenditure per capita for agricultural pesticides was reported as $32.10 in 2003. That is, for every American, $32.10 was spent on pesticides for agriculture per year.
How does America’s pesticide usage compare to the rest of the world? (2)
- World-wide expenditures on pesticides were $39.443 billion in 2007. The United States bought one-third of all of the pesticides sold in the world in 2007.
- The U.S. used 25% of all herbicides and 22% of all pesticides used in the world in 2007.
Changes in farming practices in the United States
Farming in the United States has changed since World War II. There are fewer farms and they are much larger than they were in the past. Most farming is no longer done by the owner of the land. This separation of farming and ownership has destroyed farming communities. We no longer find farmers congregating in local cafes swapping tips at 5 am. It has become an impersonal industry. (3)
Farming practices have changed to accommodate the industrial model. Farms now grow only one or two crops which substantially reduces the traditional practice of crop rotation. Animals are no longer found on farms because farming and raising livestock are now done separately. Farms now specialize.
Increased pesticide use is both cause and effect of these changes in farming practices. The drop in crop prices which made small farms unprofitable also motivated pesticide use to reduce labor costs. Pesticides were also a substitute for the crop rotations which reduced insect populations by disrupting the relationship between predator and host. Pesticides also compensated for the weed-suppressing effects of alfalfa grown to feed livestock now gone from the farm. The loss of animal manure on the farm required the substitution of chemical fertilizers. The manure which had been useful in the past is now a waste product that pollutes water from run-off from industrial-size feed lots. Separating farming from land ownership meant those using synthetic chemicals were no longer poisoning their own land and suffering the long-term consequences of their choices.
Traditional farming methods are equally effective and do less damage to the environment
The agriculture and chemical industries have been successful in convincing the public that the use of pesticides and associated farming methods were necessary to produce the food we need at the prices we are willing to pay. This fiction has thus far sustained an industry that is clearly damaging the environment and exposing the public to environmental pollution. There is growing evidence that traditional farming methods are equally effective and do less damage to the environment.
The results of a large-scale, long-term study comparing traditional farming methods with industrial farming methods were recently published. The study was conducted by the US Department of Agriculture, University of Minnesota, and University of Iowa on the research farm of the University of Iowa. They divided the research acres into three sectors and used three different farming methods to test and compare the efficacy of these methods: (4)
- Conventional method: growing only corn and soybeans in a two-year rotation cycle, using synthetic fertilizers and pesticides.
- Three-year rotation cycle, adding a crop of grains and clover.
- Four-year rotation cycle, adding a crop of alfalfa plus livestock which was fed the alfalfa.
They conducted this test over a nine-year period from 2003-2011. Here are the results of their study:
- The longer rotations of more crops produced higher yields than conventional methods: 4% more corn and 9% more soybeans. The longer rotations were also more profitable than conventional methods.
- The longer rotations required less synthetic fertilizer than the conventional method. The amount of fertilizer required by the longer rotations also decreased over time as the soil improved during the study.
- “The longer rotations reduced herbicide use by a whopping 88% with little increase in weediness.” (4)
- Longer rotations substitute labor for other inputs, but without reducing profitability.
Why aren’t traditional farming methods adopted?
As stunning as this information is, it is actually not new: “In 1989, the National Research Council investigated alternative agricultural operations such as these and reported that U.S. farming could be shifted to more natural forms without losses to yields or profits, without significantly higher food prices, and with significant gains in health and environmental protection.” (3)
The Union of Concerned Scientists explains why the public is unaware of the superiority of traditional farming methods in their article about the new study done at the University of Iowa. They tell us that the Economic Research Service of the US Department of Agriculture reports that 53% of all food and agriculture research is conducted by the private sector. Clearly the agriculture and chemical industries would not fund a study that might conclude that conventional farming methods are harmful and/or uneconomical. So, the availability of funding for such studies is limited. (4)
In the event that such a study is conducted, what are the chances that it will be published? The study done at the University of Iowa was rejected for publication by the journals Science and the Proceedings of the National Academy of Sciences. It was finally accepted by PLOS One which is solely an on-line publication. (5)
Finally, in the event that a farmer learns that traditional farming methods are less harmful to the environment and equally productive, what are the chances that he will adopt those methods? The chances are small because the farmer probably does not own the land and is therefore unconcerned about polluting it and there is no cost to the farmer associated with polluting the environment. (5)
Pesticides are a public health risk whether they are used in agriculture or in our public parks. In both cases, the good news is that it isn’t necessary to use pesticides. If the public wants to reduce the public health risks of pesticide use, they will have to speak up. Those who use pesticides are not going to stop using them unless they are forced to do so.
(1) Center for Integrated Pest Management, North Carolina State University, “Pesticide usage in the United States: Trends during the 20th Century,” February 2003. Available here.
(2) Environmental Protection Agency, “Pesticide Industry Sales and Usage. 2006 and 2007 Market Estimates.” Available here.
(3) Sandra Steingraber, Living Downstream, Addison-Wesley, 1997
(4) Karen Stillerman, Union of Concerned Scientists, “Crop Rotation Generates Profits without Pollution (or, What Agribusiness Doesn’t Want You to Know,” October 11, 2012. Available here.
(5) Mark Bittman, “A Simple Fix for Farming,” New York Times, October 19, 2012. Available here.