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.
Rice in Indonesia. Photos by Rhett Butler
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.
Tea in Kenya
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
Agricultural deforestation in Brazil
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).