Sustainable agriculture is a method of growing crops while protecting the environment, making a sizable profit, and leading to successful communities of farms. Philosophically and in practice, sustainable agriculture strives to find ways in which farmlands can be continuous producers of crops. Reliance on sources not available at the farmland, like water, soil nutrients, and appropriate amounts of sunshine, is considered unsustainable because the farm cannot self-perpetuate.
Though the term sustainable agriculture dates from the 1980's, there have certainly been attempts in the more distant past to create the best methods for farming land. In the US, for example, the pioneering work of George Washington Carver in the 19th century led to a better understanding of how crops like cotton can deplete nitrogen in the soil. Eventually, cotton growing led to non-arable land because of this depletion. Instead of artificially adding nitrogen to the soil, Carver advocated growing peanuts and sweet potatoes, which would naturally add nitrogen back to the soil. This principal of growing crops and crop rotation, which serves to improve the soil, is a hallmark of sustainable agriculture.
A farm adhering to the principles of sustainable agriculture will follow these general rules:
- Water is available directly on the land, either through rainfall, irrigation from creeks on site, or wells. Submersible pumps in wells must run on either solar or wind power, as opposed to standard electric power, which is not available on site and strips the environment of fossil fuels. Any watering system should be set to address the needs of the crop without being used in excess.
- Most pesticides are not used, as these can have a lingering impact on the environment, as well as on the people who consume whatever products are grown. Fertilizers with chemicals are also not used for the same reasons. Instead, cow manure and recycled crop waste are recommended for fertilizing crops.
- Planting one kind of crop, monoculture, is not sustainable because it will lead to soil depletion and erosion. Therefore, multiple crops should be planted with consideration to improving the soil.
- Any farm machines relying on fossil fuels are non-sustainable because they deplete natural resources. Recent studies in converting fossil fuel-reliant vehicles to the use of vegetable oils may make this a more feasible recommendation.
Sustainable agriculture additionally depends on profitability. Any farm needs money to continue to operate. This factor engenders a larger issue for those attempting to apply sustainable agriculture methods in farming. In general, produce is trucked from farms to suppliers to stores, which involves the use of fossil fuels. The depletion of fossil fuels is not sustainable, and the reliability of profits cannot be calculated because of the varying costs of fuels and labor.
Small farms, which sell directly to consumers, can more strictly adhere to the above principles. However, most people who purchase produce at farm stands still have to drive fuel-dependent vehicles to get to these farms. This issue creates difficulty in achieving true sustainability.
The principles of sustainable agriculture represent a step forward in pursuing more earth-friendly farming. However, very few farms can be defined as completely sustainable at this point. Some ecologists have proposed models for developing cities or villages where farmers would live near to other residents, thereby decreasing reliance on fossil fuels. Others suggest building community roof gardens in already established cities to increase sustainability. Though these models are still primarily conceptual, they offer an intriguing answer to the question of how we will feed the growing population of the world without further depleting our resources.