Everyone needs to eat. As the world’s population continues to increase, so does the demand for food. Although we currently produce more food than we need globally, it isn’t distributed evenly, leaving more than 800 million people hungry3. We have tried to combat this disparity by increasing crop yields through intensified agricultural efforts: bumping up the use of chemicals, both pesticides and fertilizers, and converting more land to crop fields and pastures. As of 2004, nearly 40% of the world’s land surface was used for the production of food1. Agriculture is now the most common way that humanity interacts with its environment.
Monoculture, the practice of planting of a single crop over a wide area and several consecutive years, is one component of agricultural intensification. It emerged in lockstep with the technological advancement of farm equipment. Using a tractor to plant and harvest cuts down on labor costs and increases the amount of land you can farm, and it becomes more efficient to grow crops separately, rather than mixing them within a field. But this approach comes at a high cost to the environment, human health, and the health of the animals and plants we depend on.
Biting the hand that feeds you
Monoculture farming has had a massive impact on the American landscape. More than two thirds of the USA’s 315 million acres of farmland are dedicated to producing just four crops: corn, soy, wheat and cotton2. Unfortunately this technique demands greater amounts of pesticides and fertilizers than polycultures (mixed crop fields), because it leaves crops more vulnerable to destructive pests and depletes the soil. Over the past 40 years fertilizer use has increased approximately 700%. These chemicals often have unintended negative impacts on the environment, including water pollution and eutrophication (which causes dead zones in places like the Gulf of Mexico)1.
In addition the pollution of waterways by pesticides, water reserves are threatened by intensive agriculture. The irrigation required by modern farm systems depletes freshwater resources; agriculture alone accounts for approximately 85% of global consumptive water use (water not returned to the watershed)1. This reduces the water available for human consumption, with obvious negative health consequences.
Agricultural intensification has also taken a toll directly on human health. The negative effects of pesticides have been well documented for both farmworkers and consumers and have been linked to a suite of illnesses ranging from cancer to Parkinson’s. The density livestock on industrial farms and their proximity to humans has also increased the risk of infectious disease spread1.
Adding insult to injury.
Now for the irony. Intensifying agriculture through monoculture farming may actually decrease our food security in the long term. Our current practices erode our soil (via deforestation and tillage), giving us less to farm in the future1. And by carpeting the landscape with just a few species, we are creating an ideal habitat for agricultural pests and diseases, making crops vulnerable to outbreaks and epidemics. In America, this is especially true for corn and soy, which span large, connected regions of the contiguous US2. This leaves humanity in a precarious position: although intensive agriculture is unsustainable and destructive, we must increase crop yields to feed our swelling ranks.
The situation is certainly grim, but there is reason for hope. Researchers are gaining a greater appreciation for the fact that agricultural systems are ecosystems, networks of species interactions. By generating an understanding of these relationships, we are taking the first steps toward being able to develop management strategies that enhance the natural capacity of agricultural systems with minimal inputs. This approach has the potential to increase yields without the chemical coating.
1. Foley, JA, R DeFries, GP Asner, C Barford, G Bonan, SR Carpenter, FS Chapin, MT Coe, GC Daily, HK Gibbs, JH Helkowski, T Holloway, EA Howard, CJ Kucharik, C Monfreda, JA Patz, IC Prentice, N Ramankutty, & PK Snyder. (2005). Global consequences of land use. Science, 390:570-574.
2. Margosian, ML, KA Garrett, JMS Hutchinson, & KA With. (2009). Connectivity of the American agricultural landscape: Assessing the national risk of crop pest and disease spread. Biosciences, 59:141-151.
3. Pretty, J. (2008). Agricultural sustainability: concepts, principles and evidence. Philosophical Transactions of the Royal Society B, 363:447-465.
Image credit: Attribution: Austin Valley, via Creative Commons