FPP - Sustainable Agriculture and Pesticides (Lesson)

Sustainable Agriculture and Pesticides

Agriculture is both one of humanity's greatest triumphs and the source of some of its greatest environmental problems. Agriculture uses the majority of freshwater and antibiotics, plus it causes most of the land degradation, soil loss, and loss of biodiversity. Pesticide use causes air and water pollution and has ended up all over our planet. Fertilizers and runoff from CAFOs cause eutrophication of surface waters leading to fish kills and dead zones.

Aquatic Dead Zones

 

Red circles on this map show the location and size of many of our planet's dead zones. Black dots show where dead zones have been observed, but their size is unknown. It's no coincidence that dead zones occur downriver of places where human population density is high (darkest brown). Darker blues in this image show higher concentrations of particulate organic matter, an indication of the overly fertile waters that can culminate in dead zones.

Sustainable Agricultural Methods

The methods listed and described below help minimize the impact of agriculture on the environment. One of the chief goals of sustainable agriculture is the stewardship of the land and lessening our impact.

 

Method	Description / Example
Intercropping	The cultivation of two or more crops in the same field at the same time to increase yield for the land and decrease pest issues, polyculture or polyvarietal crops are examples.
Maintain Soil Fertility	Protect soil nutrients and soil by preventing erosion, crop rotation, adequate watering, tilling organic matter into soil including cover crops, manure, crop residue, or other nutrient-rich organic material.
Limited tillage	Low or no-tillage of soil prevents erosion and allows soil pest predators to control pests by not disturbing their environment.
Managed Grazing	Livestock rotation to new pastures to prevent compacting and overgrazing of land. This allows the regrowth of grazing materials as well.
Physical Removal of Weeds	Removal of competing crops reduces the need for fertilizers and water.
Growing to Sell Locally	This supports the local economy, provides a fresher, more nutrient-rich product, and significantly reduced the use of transportation costs, packaging, and use of fossil fuels.
Use of Alternative Energy	Biodiesel can be produced and is cleaner burning and renewable when compared with fossil fuel. Other forms of alternative energy can be used to manage a farm and increase sustainability.
Cover Crops	Crops are planted along with the desired crops to protect soil, blocking aggressive competing weeds, and hold in water.
Windbreaks	Trees or shrubs are planted in rows to protect the desired crop from damaging winds and soil loss. Agroforestry is an example.
Management of Water	Improvement of water delivery systems saves both water and money. It helps protect soil quality and fertility. Drip irrigation systems are the most efficient and the use of cover crops and mulch reduces the amount of water used
Integrated Pest Management	A system of agriculture practices to produce the greatest possible crop yield with the lowest environmental and economic impact.
Attracting Beneficial Animals	Building nests or homes for animals that eat the problem pests. Like encouraging bats and birds. Beneficial insects can be purchased and used to control pests.
Strip Cropping	Planting techniques to prevent soil erosion by planting crops in strips that can capture water.
Terracing	Planting and grazing livestock so that soil quality is maintained on steep grades, and water is retained.

 

 Click here to read this publication "What is Sustainable Agriculture?" Links to an external site. from the United States Department of Agriculture (USDA).

Organic Agriculture

In the future, farming will have to be easier on the environment than in the past if agriculture is to be widely sustainable and highly productive. Organic farming is often considered as one of the solutions. Organic farming is typically considered to have three qualities: It is more like natural ecosystems than monocultures; it minimizes negative environmental impacts, and the food that results from it does not contain artificial compounds.

Organic farming is growing faster than any other agricultural segment. The USDA began certification of organic farming in 2002, and the requirements of the organic label are very strict and what types of food that can be organic are limited. Yet, according to the USDA's Organic Accomplishments 2009 - 2012, it states that in 2011 the retail value of the organic industry grew 9.5% to $31.4 billion. What does it mean for a crop to be "organic?" Please read these information sheets from the USDA, USDA  Accomplishments Links to an external site., and Labeling Organic Products Links to an external site..

 

Map (with key) of the United States showing what percentage of state farm acreage was organic in 2007

 

 

Why Pesticides?

Farmers' primary goals are to produce the greatest possible yield with the highest quality, but pests are always finding ways to beat the farmer. Whether the "pests" are insects eating the fruit, parasitic worms devastating root systems, or fungi decomposing stored crops post-harvest this has been a battle throughout the history of agriculture. Before the Industrial Revolution, farmers could do little to prevent pests and protect their crops except removing them when they appeared or use farming methods that tended to decrease their numbers. For example, slash-and-burn agriculture allows succession to take place. The greater diversity of plants and the long time between the use of each plot reduce the density of pests. Preindustrial farmers also planted aromatic herbs and other vegetation that repel insects.

Pesticides by name are intended to kill a pest, but few are pest-specific. Unfortunately, most pesticides kill much more than "target" organisms. The Cats of Borneo is a great real-life example of the consequences of the use of a nonspecific and persistent pesticide. The earliest pesticides were simple inorganic compounds that were widely toxic. One of the earliest was arsenic, an element toxic to all life (biocide), including people. It was certainly effective in killing pests, but it killed beneficial organisms as well and was very dangerous to use.

 

Please watch this video on pesticides.

 

Later, petroleum-based pesticides were developed and proved highly effective, but the ecological consequences were significant and brought to light by Rachel Carson's Silent Spring. The environmental movement grew from her exposing the impact of unregulated pesticide use. The latest trend in pesticide development is evaluating biological and ecological information, such as focusing on the pest's life cycle or looking to the environment for naturally occurring enemies of the target pests.

Pesticide use has a lasting impact on the environment due to persistence in the environment, impact on non-target species (including people), and air and water pollution. DDT, a persistent petroleum-based organochlorine pesticide, can be found in the tissues of most Americans although it was banned in the US in 1972.

Integrated Pest Management (IPM)

In the simplest terms, integrated pest management (IPM) is a system of agriculture practices to produce the greatest possible crop yield with the lowest environmental and economic impact.   Many of the practices are simple and long-standing like crop rotation and timing to minimal tillage to deter soil-dwelling pests' movement.

According to the Environmental Protection Agency (EPA), IPM means "Age-old, common-sense practices" are what many people associate with IPM. Today many growers no longer apply pesticides to food on a regular basis regardless of whether or not there are insects, weeds, or other pest problems. In some parts of the country, food is being marketed as IPM food.

Some practices for preventing pest damage may include:

• inspecting crops and monitoring crops for damage, and

• using mechanical trapping devices, natural predators (e.g., insects that eat other insects), insect growth regulators, mating disruption substances (pheromones), and if necessary, chemical pesticides.  The use of biological pesticides is an important component of IPM.

In technical terms, Integrated Pest Management (IPM) is the coordinated use of pest and environmental information with available pest control methods to prevent unacceptable levels of pest damage by the most economical means and with the least possible hazard to people, property, and the environment.

What you need to know about DDT

 

DDT (Dichloro diphenyl trichloroethane) Chemical Structure

 

Be sure to look over the following resources and links below concerning DDT.

• The DDT Story by the Pesticide Action Network of North America Links to an external site.
• The History of DDT from the EPA Links to an external site.
• DDT Factsheet from the Pesticide Information Center Links to an external site.. This factsheet discusses the impact DDT has on humans and wildlife as well as the LD50 and half-life of this persistent chemical.

To wrap up the pesticide and DDT section of this unit, read over The Story of Silent Spring Links to an external site. and Rachel Carson's impact in laying the foundation of the environmentalist movement. 

 

RESOURCES IN THIS MODULE ARE OPEN EDUCATIONAL RESOURCES (OER) OR CREATED BY GAVS UNLESS OTHERWISE NOTED. SOME IMAGES USED UNDER SUBSCRIPTION.