Agriculture, or farming, is the simplification of nature's food webs and the rechanneling of energy for human planting and animal consumption. Huh? You may ask. To simplify, agriculture involves redirecting nature's natural flow of the food web. The natural flow of the food web is-the sun provides light to plants. Plants convert sunlight into sugars which provide food for the plants(this process is called photosynthesis). Plants provide food for herbivores (plant-eating animals, i.e., sloths) and the herbivores provide food for carnivores (meat-eating animals, i.e., jaguars). Decomposers or bacteria, break down plants or animals that have died. Nutrients from the plants and animals go back into the soil and the whole process starts anew.
What happens with agriculture is that this web is interrupted. Instead of having herbivores eat the plants, the plants are protected for human consumption. This means that not only are plant eating animals excluded from the food web, but also carnivorous animals and even decomposers. However, if a farmer is planting corn to feed their cattle, the cattle eat the corn to fatten up and then are eventually slaughtered for human consumption. Even though a herbivore (cow) is eating the plant (corn) the web in interrupted when the cow is killed for human consumption.
Are there different types of agriculture?
Yes. There is conventional agriculture and sustainable agriculture (agro-ecology).
Conventional agriculture, most commonly practiced in the United States, usually involves the following criteria:
- altering or changing the natural environment (removing trees, tilling the soil, installing an irrigation system, etc.
- mono-cropping, or planting one crop (ex: only corn is grown in a plot).
- the crops grown are nonrenewable- after harvesting, the plot is bare again and requires cultivation (tilling and plowing of the soil), fertilization, planting, irrigation (watering), and harvesting all over again.
- diversity is eliminated in order to maintain uniformity
- using insecticides and pesticides to keep insects and animals from eating the crops; these chemicals are not only poisonous to insects, animals and humans, they also pollute ground water, streams, rivers, and oceans.
- using inorganic fertilizers to provide nutrients to the soil
- a lot of energy and work for the farmer to maintain this unnatural farming system; nature is more aligned with diversity (it wants to be wild), rather than controlled and uniform.
Here are some examples of crops which undergo conventional agriculture: corn, wheat, rice, bananas, soy bean, etc
What are the effects of conventional agriculture?
- since the plot is stripped of its natural environmental features, the plants are vulnerable to disease, high herbivore predation, and soil erosion.
- a decrease in bio-diversity means many animals lose their habitat and either relocate or become extinct.
- after harvesting, the plot is empty, leaving the soil bare and prone to soil erosion.
- the use of insecticides and pesticides pollutes the environment on many levels: the soil, streams, creeks, rivers, underground water sources, well water, the ocean, and even the air. When these chemicals are ingested (eaten) or inhaled, they can poison animals and people. This poisoning can cause severe illness and even death.
- crop disease, drought (no rain), fire, or heavy rain-fall can destroy a crop, thus causing severe economic hardship for the farmer and even the consumer because when the quantity of a crop is low (when the supply is low) the price is increased.
Sustainable agriculture (agro-ecology) uses ecological principles to farm, hence the prefix agro- to farm and ecology- the science of the relationship between organisms and their environments. Agro-ecology involves:
- maintaining the natural environment and using ecological principles for sustained farming practices
- poly-cropping, or planting many crops together (ex: planting rows of corn, bean, and squash together rather than in separate plots, like in mono-cropping)
- since many plants are planted together, and each one has a different harvesting period, the plot is never bare. This reduces soil erosion.
- diversity is maintained and even increased over time
- a diverse system of plants may attract several species of herbivores. Some of these herbivores like to eat specific kinds of plants. Predator species usually do not have a preference for which herbivores to eat. This predation keeps the herbivore population in check, thus reducing predation of any one crop.
- Plants- such as citrosa, are natural insect repellents. This eliminates the need to use insecticides.
- nutrients from each intercrop plant provide different nutrients to the soil, thus increasing its fertility (ability to sustain life).
- less energy is required from the farmer because the agriculture system sustains itself
Here are some examples of sustainable agriculture crops: shade coffee; multiple cropping in Germany- for example, they plant carrots, beets, and onions together in a plot; in Mexico, they do the same with corn, bean, and squash. In Italy, they plant both annual and perennial crops to create a diverse home garden; in other areas, they use cover cropping in orchards to inhibit weed growth, etc.
What are the effects of sustainable agriculture?
- using ecological principles increases bio-diversity. Not only are animals' homes salvaged (saved), but the natural ecological system protects itself (sustains itself) from soil erosion, severe herbivore predation, and crop disease.
- since insecticides and pesticides are not used, pollution and the harmful effects of ingesting these poisons are not an issue
- since each intercropping plant supplies a different nutrient to the soil, less or (even no) fertilizers are added to the soil
- this type of agriculture is aligned with nature and uses the principles of nature to sustain itself (there's nothing better than that!)
- farmers experience less or no economic loss with this type of agriculture system because the natural environment protects itself from crop disease (due to diversity of species), soil erosion (benefits of intercropping plants with different harvesting periods), flooding (the intercropping plants absorb heavy rain-falls), droughts (the intercrops provide moisture and shade for each other), and fire (extra moisture and shade keeps plants from drying out and becoming more susceptible to fire).
Which type of agriculture practice do you think is better for the environment and ultimately ourselves? Before you answer, here are some interesting facts:
Did you know that according to the FAO (Food and Agriculture Organization) that 90% of deforestation is caused by unsustainable agriculture?
Did you know that in Costa Rica, 133 ant species and 126 beetle species were found in just one shade coffee tree. Talk about diversity!
Okay, so which agricultural practice is better? Did you say sustainable agriculture? I can't hear you ...say it louder, SUSTAINABLE AGRICULTURE! You're right on the money, in more ways than one.
So, you've heard the term slash-and-burn agriculture and you're wondering what this is?
This is a type of unsustainable agriculture. It occurs in rain forests where the soil is poor in nutrients. Remember, most of the nutrients are "locked" in the leaf litter, plants, and trees. The soil gets its nutrients from the leaf litter and plants. Farmers who practice slash-and-burn agriculture know that the nutrients are "locked" in the vegetation. This is why they slash (cut) and burn the trees, plants and leaves. The ashes from the burned vegetation provide nutrients to the soil (fertilize the soil) for the planting of both staple and cash crops. After a few years, the soil loses its nutrients and the farmers migrate (move) to another piece of forest to clear and burn a new plot of land for planting.
Staple crops are plants that farmers can live on: manioc, plantains, bananas, sweet potato, pineapple, chili pepper, and others.
Cash crops are crops farmers can sell for money: sugar cane, coffee, tobacco, etc.
Is this type of agriculture harmful to the environment?
It can be if farmers raise cattle on an agriculture field that has just been farmed for 2 years (the maximum fertility of a slash-and-burn agriculture field). This can be a death sentence to the soil, since the cattle remove the last traces of fertility from the soil.
Should we blame these farmers for the deforestation of forests?
No. There are many complex factors which play into the deforestation of forests. We've already learned about logging as a major factor, but we havn't discussed the international, national, and local factors. One reason why these nomadic (traveling) farmers practice slash-and-burn agriculture is because they have no other means of employment and thus survival. They must plant crops to eat (to sustain their lives) and they must make money (by selling cash crops). If the government provided job opportunities for these farmers, maybe they wouldn't have to resort to this type of subsistence. What do you think?
An upside to slash-and-burn agriculture:
According to Kricher, a study in Costa Rica demonstrated that slash and burn does not, in the short run, degrade the soil. Researcher cut, mulched, and burned a site that contained patches of eight- to nine-year-old forest and seventy-year-old forest. Before the burn there were approximately 8,000 seeds per square meter of soil, representing 67 species. After the burn the figure dropped to 3,000 seeds/square meter, representing 37 species. Mycorrhizal fungi survived the burn, and large quantities of nutrients were released to the soil following burning. The remaining seeds sprouted, and vegetation regrew vigorously on the site (Kricher, 1997, p. 177).
What's agriculture like in Costa Rica?
Bananas are Costa Rica's number one export. This has been a blessing, in that, it has provided a lot of money to the country, but it has also created some problems. From a social perspective, the job opportunities in the banana plantations have enticed poor people from Nicaragua to immigrate to Costa Rica. This has caused tension between the Costa Rican farmers and the Nicarguan people; both groups wind up competing for jobs (working in the banana plantations). From an environmental perspective, the banana plantations cover 245,440 hectares of land, all of which used to be tropical rain forests. Supposedly, the climate is "perfect" for growing bananas. In addition, rivers have become terribly polluted with blue-plastic bags. These blue bags are used to cover the bananas while they are growing in the plantation fields. The Sarah Piqui River often has blue bags everywhere!
What about shade grown coffee?
Yes! There is a wonderful organization called CAN (Community Agroecology Network) which helps local Costa Rican farmers grow coffee in a sustainable way and earn more money per pound of coffee.
How does CAN do this?
The co-op basically cuts out all the middle-men who take money from the farmers as the coffee moves from the field to the market. When this happens, more money is left for the farmers. In fact, farmers earn even more money through this co-op than they would through conventional Fair Trade.
How do these farmers grow their coffee?
All of their coffee is shade grown and they maintain the natural, bio-diverse environment to grow their coffee. They also use sustainable planting practices such as intercropping and cover-cropping. In addition, no insecticides or pesticides are used and farmers practice reforestation as well.
How can we support these farmers?
Easy! If you want to learn more about the co-op, check out their web-site at www.communityagroecology.net. In fact, one of the CAN communities is located in Agua Buena, Coto Brus; just south of Manuel Antonio. If you'd like to order coffee, just print out the form on the web-site and send it in or order on-line. In no time, you'll receive a large bag of aromatic, organic, Costa Rican coffee at your door-step. It's the best coffee ever! This is a great gift for your parents or relatives who must have that cup of coffee in the morning.
Also, when you graduate from high-school, you can do an internship with CAN and learn how these farmers grow their coffee in a sustainable way. You can also help other coffee farmers do the same through outreach education and collaboration.
It's that time again. Show yourself what you've learned by answering the following questions:
- What is conventional agriculture and is it aligned with how the natural food-web works?
- Can you name a crop that is conventionally grown and harvested?
- What is sustainable agriculture and how is it aligned with he natural food-web?
- Can you provide an example of sustainable agriculture?
- Name one effect of conventional agriculture and how this may be harmful to the environment.
- Name one effect of sustainable agriculture and how this benefits the environment.
- Which agricultural practice is better for the environment and ultimately ourselves?
- T or F. Slash-and-burn agriculture is not harmful to the environment if the land is used for 2 years or less.
- Match each term with its meaning:
staple crops a.) no rain
nomadic b.) a co-op which helps coffee farmers
drought c.) sugar cane, coffee, tobacco, etc
cash crops d.) traveling
CAN e.) plantains, sweet potato, bananas
10. T or F. Poor farmers are to blame for the deforestation of rainforest.
Answers are located after the references.
Pen Pal Question and Conversation: Discuss with your Pen Pal what you can do as global citizens to encourage sustainable agriculture. How would you encourage your friends, family members, and local farmers to do the same?
Kricher, J. (1997). A Neotropical Companion: An introduction to the animals, plants, & ecosystems of the New World Tropics. New Jersey: Princeton University Press.
A chapter, Introduction To Agroecology, from a book by Greg Gilbert.
Answers to the questions:
- Conventional agriculture is most commonly practice in the U.S. and it involves changing the environment to plant crops for human beings. It is not aligned with how the natural food-web works because the plants are protected for human consumption. This means that herbivores, carnivores, and even decomposers are left out of the picture.
Sustainable agriculture (agro-ecology) uses ecological principles to farm, hence the prefix agro- to farm and ecology- the science of the relationship between organisms and their environments.
shade grown coffee
Insecticides and pesticides are harmful to the environment because they pollute the soil, streams, creeks, rivers, underground water, well water, and oceans. They are harmful to animals and humans because they are poisonous and can cause serious illness and even death.
Intercropping adds nutrients to the soil, prevents erosion, and provides moisture and shade to the other plants within the plot.
staple crops e.) plantains, sweet potatoes, and bananas
nomadic d.) traveling
drought a.) no rain
cash crops c.) sugar cane, coffee, and tobacco
CAN b.) a co-op which help coffee farmers
How did you do? I'm sure you did FANTASTIC!
The following standards were addressed in this lesson:
Physcial Sciences: Energy and matter have multiple forms and can be changed from one form to another. As a basis for understanding this concept (a) Students know energy comes from the Sun to Earth in the form of light, and (b) Students know sources of stored energy take many forms, such as food, fuel, and batteries. Note: This lesson address food as a source of stored energy.
Life Sciences: Students know living things cause changes in the environment in which they live: some of these changes are detrimental to the organsim or other organisms, and some are beneficial.
Reading: Vocabulary and Concept Development (1.6) Use sentence and word context to find the meaning of unknown words (1.8) Use knowledge of prefixes (e.g., un-, re-, pre-, bi-, mis-, dis-,) to determine the meaning of words.
Writing: Organization and Focus (1.1) Create a single paragraph (a) Develop a topic sentence, and (b) Include simple supporting facts and details.
Social Studies: 3.5 Students demonstrate basic economic reasoning skills and an understanding of the economy of the local region. (1) Describe the ways in which local producers (and abroad) have used and are using natural resources, human resources, and capital resources to produce goods and services in the past and the present.
The Mongabay Kids site (kids.mongabay.com) aims to help children learn about rainforests and the environment. This site is still under development and I am working to add additional content as time permits. If you have comments or are interested in submitting educational content for the site, please feel free to contact me.
The site is available in many different languages, including Portuguese, Chinese, French, Spanish, Japanese, and German.