A sustainable food supply appears to be the new catch phrase for agriculture in the 21st century. And the concept of locally grown foods is often translated by many as a sustainable practice. Locally grown foods are typically said to require less fuel, thus having lower carbon footprint. The idea of eating only locally grown foods has become so trendy that now we have a word to describe the practice, "locavore."
To be a locovore, the challenge and adventure is finding foods from within a determined radius from home. The practice of eating locally can create a greater connection between consumers and their food sources and support the local economy. This movement is strong and many see an opportunity for new enterprises or a new way of surviving a troubled economy.
In Europe, where people have been stacked on top of each other for generations, land for local production is not easily available nor cheap. To replace the need for large expanses for food production, farmers use modern technologies. These include highly automated greenhouses as well as multi-level greenhouse structures. In our down-turned economy and with the drive for local foods, many are considering many technologies for local food production.
Sounds great, doesn't it? Well many seem to think so. So many that I am getting several inquiries on how to start a business. Where are they seeing this? Many are curious after reading media releases about those whom are constructing new projects or perhaps they just returned from EPCOT at Disney World in Orlando, Florida. The Land Pavilion has a grand display of intensive agricultural practices. Yet, are they sustainable?
So let's look at some facts. Below is a table that lays out an analysis for the production of lettuce in a greenhouse that is 3,072 square feet in size. These data were generated based on typical production yielding 59,000 heads (5 ounces) of lettuce per year with a market value of $1.10 per head, farm gate.
|Per Square Foot|
Here you can see that it is possible to make money on lettuce production in a greenhouse, providing you can maintain a sustainable price structure and consistent clientele.
Now let's add the fish. Based on several web sites that promote aquaponic production using tilapia (Nile tilapia, or Oreochromis niloticus), I am going to estimate that one can expect to yield about 0.75 pounds of fish per square foot of greenhouse space per year. For the greenhouse described above, this equates to about 2,275 pounds of fish per year. In 2004, the USDA valued tilapia at $1.72 per pound, farm gate, which equates to $3,913 per year in gross value. Rembember, this is for fish in the greenhouse, not the headhouse.
The greenhouse described in this scenario if built for lettuce, would cost about $23,000 or $7.55 per square foot to build. A kit ready system based on a similar size greenhouse and fish production facility would cost about $41,000 or $13.40 per square foot. This equates to a 78% increased cost to build, which equates to a $8,200 per year cost of ownership (based on 20% of the initial costs).
The lettuce scenario includes all variable costs, such as labor, labels, tags, boxes, sales, etc. The aquaculture component does not as I don't have any ideas on what they may be. But based on these rough calculations, lettuce and tilapia grown together will cost about $89,000 per year to raise for a gross income of $68,800 per year. Or a net loss of more than $20,000 per year.
Arguments for aquaponics as published by the National Sustainable Agriculture Information Service is managed by the National Center for Appropriate Technology (NCAT) promote aquaponics serves as a model of sustainable food production by following certain principles:
- The waste products of one biological system serve as nutrients for a second biological system.
- The integration of fish and plants results in a polyculture that increases diversity and yields multiple products.
- Water is re-used through biological filtration and recirculation.
- Local food product ion provides access to healthy foods and enhances the local economy.
- Hydroponic growers view fish manured irrigation water as a source of organic fertilizer that enables plants to grow well.
- Fish farmers view hydroponics as a biofiltration method to facilitate intensive recirculating aquaculture.
- Greenhouse growers view aquaponics as a way to introduce organic hydroponic produce into the marketplace, since the only fertility input is fish feed and all of the nutrients pass through a biological process.
- Food-producing greenhouses—yielding two products from one production unit—are naturally appealing for niche marketing and green labeling.
- Aquaponics can enable the production of fresh vegetables and fish protein in arid regions and on water limited farms, since it is a water re-use system.
- Aquaponics is a working model of sustainable food production wherein plant and animal agriculture are integrated and recycling of nutrients and water filtration are linked.
- In addition to commercial application, aquaponics has become a popular training aid on integrated bio-systems with vocational agriculture programs and high school biology classes.