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Why Organic Landscaping?
(Excerpted from the Northeast Organic Farming Association (NOFA) Organic Lawn and Turf Handbook, 2007)
First, What is Organic?
The word “organic,” as we use it here, comes from organic agriculture. The ideas and methods of organic agriculture have been developed over the last 60 years through a rich exchange among farmers, researchers and activists all over the world. The mission of the NOFA Organic Land Care Program is to extend the vision and principles of organic agriculture to the landscapes where people spend their daily lives.
The primary goals of organic land care are:
- Maintaining soil health;
- Eliminating the use of synthetic pesticides and synthetic fertilizers;
- Increasing landscape diversity;
- Improving the health and well being of the people and web of life in our care.
The full definition of organic land care – how we apply those goals to the real world – is fleshed out in the NOFA Standards for Organic Land Care: Practices for Design and Maintenance of Ecological Landscapes. This publication covers a very broad range of landscape and environmental issues. Some important points that apply to organic lawns and turf include:
- No synthetic pesticides, including insecticides, fungicides and herbicides;
- No synthetic fertilizers;
- No genetically engineered organisms;
- Building healthy soil that can support diverse soil life as well as strong growth of healthy grass;
- Reducing the potential for nitrogen or phosphorus pollution by limiting the amount of organic fertilizers applied and adjusting the timing of application;
- Using good cultural practices to encourage the growth of healthy grass and reduce the need for irrigation and other inputs;
- Increasing diversity of plant cultivars and species where appropriate – depending on how the lawn will be used and the standards of the client.
There is, of course, a completely different meaning of the word “organic,” one that refers to molecules that contain carbon atoms, as in “organic chemistry.” This is not the meaning we are using here. This other definition sometimes causes confusion with respect to fertilizers. Fertilizers that include ingredients like sewage sludge or urea, which are not acceptable under organic standards for agriculture or land care, sometimes are labeled “organic” under the “organic chemistry” definition.
Concerns About Pesticides
The demand for organic lawns and athletic turf is driven by concerns about human health and the environment. Organic management is beneficial to human health and the environment in many ways: eliminating the use of synthetic pesticides; building a diverse, robust ecological system that holds nutrients and water; reducing pollution due to leaching and run-off; and recharging groundwater and streams with clean fresh water. Because concerns about pesticides are foremost in the minds of the general public, this chapter will focus on pesticide issues.
A pesticide, according the U.S. Environmental Protection Agency, is “any substance intended for preventing, destroying, repelling, or mitigating any pest.” Pests include a wide range of “living organisms that occur where they are not wanted or cause damage to crops or humans or other animals.” In addition to insects, these include weeds, fungi, bacteria and viruses that cause disease in plants, and animals such as mice and slugs that attack desirable plants or occur where they aren’t wanted (1).
Pesticides may be needed in certain situations to protect against the spread of human pathogens. However, evidence of harmful effects of pesticides on human health and the environment has increased steadily since the first alarms were raised by the book Silent Spring in 1962. As the evidence has accumulated, some pesticides that once were widely used have been restricted or banned. These pesticides were, of course, hazardous to human health and the environment all along, but the hazards were only recognized and established through scientific studies after many years of use.
There are several reasons why it takes so long to fully understand the hazards of pesticides, even those on the market today:
There can be a long time between pesticide exposure and the appearance of chronic disease. Cancer in humans, for example, may show up 20– 30 years after exposure to a carcinogenic pesticide (2).
There may be a critical time in development when pesticide exposure will result in major health problems much later in life. Studies have shown that fetuses and young children are particularly sensitive to the effects of pesticides (3,4). These effects may show up as cancer, as deformities of the reproductive system or as effects on the development of the nervous system, which affect learning and behavior, but are only detected years after the exposure.
New studies (5,6) are also showing that exposure of a parent to pesticides is associated with birth defects, cancer and reproductive effects in the next generation. This includes exposure of fathers, not just pregnant mothers.
Scientists continue to discover new risks associated with pesticides that were not known 20 or 30 years ago. The entire field of endocrine disruption, the study of the interference of synthetic chemicals in the normal signals carried by hormones throughout the body, has developed tremendously since the landmark book on the subject, Our Stolen Future, was published 10 years ago (7). One of the surprising discoveries has been that pesticides and other synthetic chemicals can have adverse effects on hormonal systems in mice at very low concentrations – much lower than had previously been considered a hazard (8). There has been great resistance to incorporating this information into government regulatory requirements because it would require setting limits for human exposure that are hundreds or thousands of times lower than they are today.
We are all exposed to a mixture of pesticides and other potentially harmful chemicals in our environment. A recent Environmental Working -2 Group study found an average of 200 contaminants (industrial chemicals, pesticides and other pollutants) per baby in the umbilical cord blood of newborns (9), and other studies have also shown a “body burden” of dozens to hundreds of these contaminants in every person in the U.S. (10). This makes studies of environmental chemicals and disease in the human population difficult because we are all exposed at some level – there is no unexposed population to serve as a control group. In addition, there is increasing evidence that combinations of chemicals can have much greater effects than each one separately (11,12), increasing the hazard and also the difficulty of scientific study.
To evaluate the effects of pesticides on “nontarget” organisms, the Federal government requires that tests to determine acute toxic effects be conducted on just a few indicator species (such as bobwhite quail, rainbow trout, carp and honey bees) before a pesticide can be registered. These tests cannot predict the effects of pesticides on the universe of other animals, plants, microbes and ecological systems.
There are only a few studies on the effects of long-term, low-level exposure on non-target organisms. In shore nesting herons, for example, the organophosphate and carbamate insecticides found in the diets of the chicks do not kill them outright, but affect their behavior so that they are more susceptible to attack by scavenging beetles in the nest and by predators (13). Detailed studies of the effects of a mixture of pesticides, each at very low concentration, on frogs found multiple subtle effects: delayed metamorphosis, reduced size and immunosuppression leading to bacterial infection (12). One study found that an insecticide and a fungicide, both known to be endocrine disruptors in mammals, also interfered at very low concentrations with the signaling between a leguminous plant and the symbiotic bacteria that fixes nitrogen in its roots (14).
Thus, the arguments for eliminating pesticides or increasing restrictions on pesticide use are:
- There is considerable scientific evidence that associates cancers, birth defects, hormonal disruption and neurological effects with pesticides still used today (15).
- There is also evidence of damage to wildlife and ecological systems (13).
- Pesticides that are now recognized as hazardous were widely used for years, exposing millions of people and sensitive ecological systems before the pesticide hazards were adequately understood.
- Even after hazards have been scientifically demonstrated, additional legal and political pressures are often required to restrict or eliminate even the most hazardous pesticides.
- The relationships between pesticide exposure and human illness are inherently time-consuming to study. Even a strong relationship may be difficult to prove in a timely and efficient way. If, as demonstrated in animal studies, a parent’s pesticide exposure can result in damage to the reproductive system for four subsequent generations (16), then the effects of our current pesticide use may not be fully evident for many decades to come.
- Lack of proof of harm is not necessarily evidence of safety. It can also mean that a possible harmful effect has not yet been studied, or that studies thus far have not yielded a clear result. As discussed above, some effects of pesticides take many years and a large research commitment to demonstrate conclusively.
In organic agriculture, and now in organic land care, the philosophy has always been to avoid the use of pesticides as much as possible through management of the entire ecological system to avoid pest problems. These non-chemical methods – such as planting insect- and disease-resistant varieties, avoiding monocultures, building healthy soil with diverse soil life and altering growing conditions to reduce susceptibility to pests and disease – are listed as “Preferred” in the NOFA Standards for Organic Land Care, which have been developed and published by the NOFA Organic Land Care Program.
The NOFA Standards for Organic Land Care uses a standard for evaluating the active ingredients of pesticides that is similar to that used by the USDA National Organic Program for organic agriculture, but does not attempt to evaluate inert ingredients of pesticides. This means that the standard of the National Organic Program for pesticides is higher than that of the Organic Land Care committee, and any pesticides approved by the Organic Materials Review Institute (OMRI) for use in organic agriculture would also be allowed under the NOFA Standards for Organic Land Care. There are additional materials, such as the spinosad insecticide Conserve®, and the iron phosphate molluscide Sluggo®, that are allowed under organic land care standards but not under USDA standards because of the presence of either undisclosed or synthetic inert ingredients.
Note that OMRI-approved fertilizers are NOT necessarily allowed under organic land care standards. The Organic Land Care Committee has maintained a different position than that of the National Organic Program about the highly soluble, mined fertilizer sodium (Chilean) nitrate. The Organic Land Care Committee decided that Chilean nitrate is not acceptable in organic land care. Thus, fertilizers that are OMRI-approved for organic agriculture but contain Chilean nitrate would be prohibited under organic land care standards.
In both organic agriculture and organic land care, some pesticides are allowed. Organic standards have always been much more restrictive than those of the U.S. government. The basic principles used in deciding which pesticides to allow are that allowed pesticides should be based on natural products, not synthetic chemicals, and natural products that are known to be highly toxic (such as nicotine) are not allowed. Some specific examples of pesticides allowed in organic agriculture and land care are:
- Microbial pesticides, such as Bacillus thuringiensis (Bt), spinosad, Milky Spore®, Beauveria bassiana (a fungus that attacks insects) and formulations of microbes that are antagonists or competitors of plant pathogens;
- Botanical pesticides, such as pyrethrin, neem, hot pepper wax and clove oil, as well as plantbased horticultural oil;
- Certain mined products, such as petroleumbased horticultural oil, potassium bicarbonate and diatomaceous earth;
- Insecticidal soaps.
These choices were made over the years in organic agriculture by farmers and activists, who did not have the resources to do elaborate testing of the vast array of natural and synthetic pesticides in order to decide which posed the least hazard to human health, ecologically sound farming systems and the environment. Although some scientists criticize organic agriculture and land care for using the distinction between natural and synthetic materials in making choices, this distinction has held up quite well over the decades.
Synthetic pesticides are more likely to persist, spread to non-target sites and bioaccumulate (concentrate in living organisms) than pesticides based on natural products because synthetic chemicals represent new chemical structures that have never before occurred in biological systems (17). Enzymes and organisms that break down synthetic pesticides to harmless components may not exist or may not act rapidly enough to prevent the pesticide from becoming a widespread pollutant. This has been seen many times in the history of synthetic pesticides and many other synthetic chemicals. One example is DDT, whose toxic breakdown products have been found in the bodies of human beings all over the planet, from remote villages in Papua, New Guinea, to the high Arctic (18). Another more recent example is imidacloprid, which was discovered in groundwater after only 9 years of use on Long Island (19).
The only pesticides based on natural materials that have a history of long-term persistence, of spreading to non-target sites or of bioaccumulating are those based on mined materials, particularly lead and arsenic. These pesticides were widely used in conventional agriculture in the early 20th century, but were never allowed in organic agriculture because the toxicity of these materials was already well recognized (although we know a great deal more now about their hazards, especially at low concentrations) (20,21).
All pesticide use, including pesticides that are allowed in organic land care, involves some risk. One should seriously consider all possible nonchemical alternatives before using any pesticide, and take appropriate safety precautions. The legal restrictions on pesticide use (based on Federal law and laws in Connecticut and Massachusetts) are discussed in Appendix I.
There are cases where pesticides may have benefits exceeding their risks. For example, when insects spread pathogens that cause human disease, it is appropriate to evaluate the judicious use of pesticides against other alternatives in protecting public health. Pesticides may also be needed in other emergency situations, such as limiting the spread of new invasive species of insects or plant pathogens.
However, in this handbook, we are discussing lawns and athletic turf. Lawns and athletic turf provide clear benefits to humans. They offer a pleasant and useful environment for our activities. Well-managed lawns and athletic turf also provide environmental benefits by reducing soil erosion and water runoff.
But, as this handbook will demonstrate, synthetic pesticides are not essential for growing healthy lawns and turf. And much of the pesticide use on lawns and turf is for purely cosmetic purposes – to create a certain standard of appearance – which does not serve the needs of people or protect the environment.
Thus, it can be argued that the risks of using synthetic pesticides to grow lawns and turf – particularly the risks to the health of the people applying the pesticides, to those living near and playing on the turf and to the surrounding environment – are much greater than the benefits to human health and the environment. The decision, in the end, is up to you, the lawn and turf professionals, and the clients and communities you serve.
Written by Kimberly A. Stoner, Ph.D., of the Connecticut Agricultural Experiment Station and the Organic Land Care Committee.
Resources and References
Carson, Rachel. 1962. Silent Spring. Houghton Mifflin Books.
Colborn, T., D. Dumanoski, J.P. Meyer. 1996. Our Stolen Future: How We Are Threatening Our Fertility, Intelligence, and Survival. Penguin Books.
Krimsky, S. 2000. Hormonal Chaos: The Scientific and Social Origins of the Environmental Endocrine Hypothesis. Johns Hopkins University Press.
Schettler, T., G. Solomon, M. Valenti, A. Huddle. 1999. Generations At Risk: Reproductive Health and the Environment. MIT Press.
Wargo, J. 1996. Our Children’s Toxic Legacy: How Science and Law Fail to Protect Us From Pesticides. Yale University Press.
U.S. Environmental Protection Agency - “About Pesticides”
Cornell Extension Toxicology Network: http://pmep.cce.cornell.edu/profiles/extoxnet/
National Pesticide Information Center (Oregon State University): http://npic.orst.edu/nptnfact.htm
Scientific Reviews of Pesticide Hazards (pesticides may also be included in broader reviews of chemical hazards):
Overview of the hazards of pesticides in the landscape to the public:
Ontario College of Family Physicians. 2004. “Pesticide Literature Review: Systematic Review of Pesticide Human Health Effects.” http://www.ocfp.on.ca/local/files/Communications/Current%20Issues/Pesticides/Final%20Paper%2023APR2004.pdf
Overview of pesticide effects on humans and other vertebrates:
Parsons, K.C. et al. 2005. “Sublethal Effects of Exposure to Cholinesterase-inhibiting Pesticides: Humans and Vertebrate Wildlife.” Manomet Center for Conservation Sciences. http://www.manomet.org/pdf/SublethaleffectsofexposuretoChE-inhibitorsreport.pdf
Database of chemicals (including pesticides) and risk of breast cancer:
Cornell University. 2006. EnviroChem and Cancer Database: http://envirocancer.cornell.edu/eccd/print.cfm
Specific References to the Scientific Literature:
1. U.S. Environmental Protection Agency – “About Pesticides” http://www.epa.gov/pesticides/about/#not
2. Clapp, R., G. Howe, M.J. Lefevre. 2005. “Environmental and Occupational Causes of Cancer: A Review of the Recent Scientific Literature.” University of Massachusetts Lowell. http://www.sustainableproduction.org/downloads/Causes%20of%20Cancer.pdf
3. Wargo, J. 1996. Our Children’s Toxic Legacy: How Science and Law Fail to Protect Us From Pesticides. Yale University Press;
Zahm, S.H. and M.H. Ward. 1998. “Pesticides and Childhood Cancer.” Environmental Health Perspectives 106 (Suppl 3):893-908 (1998). http://www.ehponline.org/members/1998/Suppl-3/893-908zahm/zahm-full.html
4. Colborn, T. 2006. “A Case for Revisiting the Safety of Pesticides: A Closer Look at Neurodevelopment.” Environmental Health Perspectives 114:10–17 (2006). http://www.ehponline.org/docs/2005/7940/abstract.html
5. Garry, V. et al. 2002. “Birth Defects, Season of Conception, and Sex of Children Born to Pesticide Applicators Living in the Red River Valley of Minnesota, USA.” Environmental Health Perspectives 110 (suppl 3):441-449 (2002). http://www.ehponline.org/members/2002/suppl-3/441-449garry/garry-full.html
6. Birnbaum, L.S. and S. E. Fenton. 2003. “Cancer and Developmental Exposure to Endocrine Disruptors.” Environmental Health Perspectives 111:389–394 (2003). http://www.ehponline.org/members/2003/5686/5686.pdf
7. Colborn, T., D. Dumanoski, J.P. Meyer. 1996. Our Stolen Future: How We Are Threatening Our Fertility, Intelligence, and Survival. Penguin Books.
8. Welshons, W.V. et al. 2003. “Large Effects from Small Exposures. I. Mechanisms for Endocrine-Disrupting Chemicals With Estrogenic Activity.” Environmental Health Perspectives 111: 944-1006 (2003). http://www.ehponline.org/members/2003/5494/5494.pdf
9. Environmental Working Group. “Body Burden Profile: Overview of All Test Results.” http://www.ewg.org/bodyburden/results.php
10. Centers for Disease Control 2005. Third National Report on Human Exposure to Environmental Chemicals. http://www.cdc.gov/exposurereport/3rd/pdf /thirdreport_summary.pdf
11. Cavieres, M.F., J. Jaeger, W. Porter. 2002. “Developmental Toxicity of a Commercial Herbicide Mixture in Mice: I. Effects on Embryo Implantation and Litter Size.” Environmental Health Perspectives 110:1081–1085 (2002). http://www.ehponline.org/members/2002/110p1081-1085cavieres/cavieres-full.html
12. Hayes, T.B., et al. 2006. “Pesticide Mixtures, Endocrine Disruption, and Amphibian Declines: Are We Underestimating the Impact?” Environmental Health Perspectives 114 (sup 1) 40-50 http://www.ehponline.org/members/2006/8051/8051.html
13. Parsons, K.C. et al. 2005. “Sublethal Effects of Exposure to Cholinesterase-inhibiting Pesticides: Humans and Vertebrate Wildlife.” Manomet Center for Conservation Sciences. http://www.turi.org/content/content/view/full/3420/
14. Fox, J.E., et al. 2001. “Nitrogen Fixation: Endocrine Disrupters and Flavonoid Signalling.” Nature 413: 128-129.
15. Ontario College of Family Physicians. 2004. “Pesticide Literature Review: Systematic Review of Pesticide Human Health Effects.” http://www.ocfp.on.ca/local/files/Communications/Current%20Issues/Pesticides/Final%20Paper%2023APR2004.pdf
16. Anway, M.D. et al. 2005. “Epigenetic Transgenerational Actions of Endocrine Disruptors and Male Fertility.” Science 308: 1466- 1469.
17. Duke, S.O. 1990. “Natural Pesticides from Plants.” pp. 511-517. In: J. Janick and J.E. Simon (eds). Advances in New Crops. Timber Press, Portland, OR. http://www.hort.purdue.edu/newcrop/proceedings1990/v1-511.html
18. Ritter et al. 1995. “Persistent Organic Pollutants: An Assessment Report on DDT, Aldrin, Dieldrin, Endrin, Chlordane, Heptachlor, Hexachlorobenzene, Polychlorinated Biphenyls, Dioxins and Furans.” International Programme on Chemical Safety. Arctic Monitoring and Assessment Programme. 1997. “Arctic Pollution Issues: A State of the Arctic Environment Report.” Oslo, Norway. http://www.chem.unep.ch/POPS/alts02.html
19. New York State Department of Environmental Conservation. Letter to Ms. Margaret Cherny, Bayer Crop Science. http://pmep.cce.cornell.edu/profiles/insect-mite/fenitrothion-methylpara/imidacloprid/imidac_let_1004.pdf
20. Schnaas, L. et al. 2006. Reduced Intellectual Development in Children with Prenatal Lead Exposure. Environmental Health Perspectives 114: 791-797 (2206). http://ehp.niehs.nih.gov/docs/2005/8552/abstract.html
21. Andrew, A.S. et al. 2006. “Arsenic Exposure Is Associated with Decreased DNA Repair In Vitro and in Individuals Exposed to Drinking Water Arsenic.” Environmental Health Perspectives (in press). http://www.ehponline.org/members/2006/9008/9008.pdf