Sunday, April 29, 2012

The Demise of Conventional Agriculture 

Hopefully most people around the world have heard of climate change, one of the most challenging issues we are facing today. We also have heard of the issues contributing to climate change: we have too many people on earth, there are too many urban areas, there is too much pollution, and we are losing too much biodiversity. What each of these issues have in common is their relation to the globalized agriculture industry. Agriculture takes up 40% of the earth's land surface which is 60% larger than areas commonly complained about: urban sprawl. What many people don't know is the extent of the impact that our global agriculture industry has on the earth and its organisms, including us. The largest cause of habitat loss around the world is from clearing habitat for the purpose of cultivating crops or farming animals. This habitat loss due to the agriculture industry creates the largest impact on biodiversity worldwide.

Here is an image from 2006 showing the distribution of land used for agriculture around the world (Ahlenius, 2006). The different colors show the ratio of cropland versus grazing land. We can see just about every habitable place on earth is used for agricultural purposes, where most of the remaining areas are barren, deserts, ice, or mountains. Since this image was published, many of the few biodiverse hotspots that were once intact have been exploitated for agriculture use or oil exploration.

The agriculture industry does more than take up space.  Out of the total amount of water used by humans, the agriculture industry uses about 70%. Impacts of this water use are observed widely around the world. For example today, the Colorado River in the western United States no longer reaches the sea due to the intensive withdrawal used for agriculture and drinking water. The Aral Sea is also almost completely dried up as a result of the diversion of its incoming rivers for irrigation.

The impacts of the agriculture industry reach farther than the earth's land and water, but also into our atmosphere. The largest human contribution to global climate change is directly from the agriculture industry, totaling to about 30% of the total greenhouse gas emissions caused by humans. The largest contributors to this impact from agriculture are methane emissions from cows and rice, carbon dioxide emissions from burning tropical rainforests for clearing, nitrous oxide from too many fertilizers, and we have doubled the flows of nitrogen and phosphorous due to the use of fertilizers. The increase in these flows creates many negative impacts including eutrophication of water bodies and water pollution. Jonathan Foley, professor and director of the Institute on the Environment at the University of Minnesota, calls this impact of the agriculture industry, "The Other Inconvenient Truth" in a lecture of his, given in 2010 (Foley, 2010).

Looking at all of these negative impacts may be depressing and infuriating, but we all know that this is the very industry that keeps most of the seven billion people on earth alive and (somewhat) healthy. So what can we do to reduce the impacts of one of the most problematic and prevalent industries in the world? We can model it after Mother Nature herself. Natural ecosystems have unreal amounts of interacting organisms and processes that keep the ecosystems in balance and healthy.  But  humans have tended to mess that balance up. Using methods like permaculture, intercropping, biopesticides, natural predators, and agroforestry, we can improve our methods of producing food to work with the ecosystem and not against it. Creating an ecosystem in these ways allows humans to benefit from the natural ecosystem services provided in a habitat.

Some of the relevant ecosystem services in agroecosystems include:
  • Biological pest control: Non-crop environments provide habitat and numerous food sources for natural insect and parasite predators, like insectivorous birds and bats. These organisms provide an ecosystem service to the agroecosytem by naturally controlling pests.
  • Pollination: 35-40% of the total volume of food produced by crops rely on animal pollination. Insects and animals provide the ecosystem service of pollination in agricultural settings as well as almost all other places on earth.
  • Water quantity and quality: Vegetation in natural ecosystems regulates capture, infiltration, retention, and flow of water, throughout the habitat. Soil and plants act as a filter for the incoming water, purifying it naturally, providing an essential ecosystem service. The plants' roots keep hold of the soil, reducing erosion. Plant cover also largely regulates many other aspects of the soil including water retention.
  • Soil structure and fertility: Aeration and abundance of organic matter in soils are essential to nutrient uptake by crops. The presence of plant cover produces litter for decomposition and nutrients, and the movement of invertebrates through the soil creates aeration. Many micro and macro organisms in the soil, such as earthworms and bacteria, regulate the decomposition and availability of nutrients to crops, also providing a fundamental ecosystem service. (Power, 2010).
 An optimal system in agriculture allows for each of these ecosystem services to interact and naturally regulate possible negative processes, provide goods, support beneficial processes, and with a more natural feel to the habitat, there is an appeal to the human senses that gives cultural benefits (Fiedler et al., 2008).

Micheal Pollan describes the agroecosystem of a farmer in Virginia, who uses these interactions on his farm. The farm incorporates ecosystem services that are present in natural ecosystems. One of the aspects of his permaculture farming occurs between the cows, chicken, and the grass (and many other small critters). 

First, the farmer grazes the cattle on a fenced off quarter acre. The farmer then waits three days, and then brings in hens to the previously grazed area. The chicken immediately beelines for the cow patties in search for the larva of flies that have made homes in the dung. The farmer waits three days because on the fourth or fifth day the larva will hatch and produce many flies. So at the time the chickens are released into the pen, the larva are nice and fat and juicy for them to eat. While the chicken are stuffing their mouths they are breaking up and spreading the cow feces while also adding some of their own feces, which is rich in nitrogen. The mixture of feces becomes fertilizer for the grass and in about three weeks the grass is thriving and growing tall. At this point the farmer can come in and cut the grass to sell as hay. About 4-5 weeks later the farmer can use this same plot again, but he can move to a different quarter acre in the mean time, and even use a different species such as sheep. 

From this farm there are many foods produced such as beef, pork, eggs, chicken meat, turkey, rabbit, and other products like grass, hay, and more importantly new soil. The new soil is produced from the critters that decompose some of the grass' roots that are lost after cutting the grass. This loss of roots is due to the grass' need to maintain a certain root/shoot ratio (Pollan, 2007).

The last 7 minutes of this video describes the workings of this aspect of the farm in Virginia. The first ten minutes are interesting as well as Pollan describes an interesting perspective of the interactions between human and non-human organisms.

This is one example of how an agroecosytem thrives when the organisms are free to do what they naturally want to do, working together in symbiotic relationships. These techniques of farming are important for the reduction of the negative impacts of the agricultural industry and, if supported, will hopefully lead to the demise of conventional agriculture.

 Fiedler, Anna K., Doug A. Landis, and Steve D. Wratten. "Maximizing Ecosystem Services from  Conservation Biological Control: The Role of Habitat Management." Biological Control 45 (2008): 254-71. Science Direct. Elsevier, 11 Jan. 2008. Web. 26 Apr. 2012.

Foley, Jonathan. "The Other Inconvenient Truth." TEDx. Oct. 2010. Speech.

 Pollan, Micheal. "The Omnivore's Next Dilema." Monterey, CA. Mar. 2007. Speech.

Power, Alison G. "Ecosystem Services and Agriculture: Tradeoffs and Synergies." Phil. Trans. R. Soc. B 365 (2010): 2959-971. Royal Society Pulishing. The Royal Society, 2010. Web. 26 Apr. 2012.

Images: (in order of appearance)
 Ahlenius, Hugo, and UNEP/GRID-Arendal. "Agriculture Land Use Distribution - Croplands and Pasture Land." Map. Global Environment Outlook 4 (GEO-4). UNEP GRID-Arendal, 2006. Web. 26 Apr. 2012.

USGS. The Vanishing Aral Sea. 2009. Photograph. Land Satellite, Kazakhstan and Uzbekistan. Landsat Update 2009. USGS, 2009. Web. 26 Apr. 2012.

Cicadas. FRESH FOOD. Photograph. Flickr. Mother Nature Network. MNN Holdings. Web. 26 Apr. 2012.

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