The Art of Engineering

Urban agriculture (UA) – the production of food within a city – is an important aspect of securing our food supply as well as restoring our communities. There are some obvious and immediate benefits to urban farming, such as bringing our food closer to us and reducing transportation energy, but the impact and benefits are far reaching, especially in cities with large impoverished communities. There are at least four major ways in which we can benefit:

1. Access to a local, fresh, organic, varied diet,
2. Community upliftment,
3. Effective use of land,
   
4. Improved food security.

Local, fresh, organic, varied diet. Many people focus on "food miles" but this has a lot more to do with our buying patterns rather than where our food is grown. One of the restrictions with UA is the amount of land available which means that biointensive methods of farming must be used. These methods farm small amounts of land using organic methods to produce high crop yields and simultaneously improve the soil quality. This method also requires companion planting. All together this means higher quality fresh food with less or no storage (no artificial ripening), as well as carbon and heat sinks within the city.

Community upliftment. Many cities (certainly in developing countries) have large improverished communities as a result of rural to urban migration and many other societal conditions. UA offers a number of benefits for these communities, the biggest of which is access to food. The first output of urban farms in these communities is food for the community. Once the immediate needs of the community are met any excess food can be sold for income. Improvement of the soil quality and the greening of these communities also help to improve living conditions.

Effective use of land. Unproductive vacant lots, parts of parks and gardens can be turned into productive farms. These farms will require organic waste materials to produce compost which reduces the load on cities waste management facilities.

Improved food security. UA is a distributed model of farming which helps to buffer the communities that it serves against any variations in food supply. If there was a failure in the food supply chain, or if transport costs significantly raised the price of food, UA communities would still be able to access food – hopefully for an extended period of time. Cuba is an interesting extreme example of this. The shutting down of foreign supplies resulted in unused areas within the cities being used to produce food crops and support the country's food need. The distributed model also means that a failure of a single UA farm would not significantly impact on the food supply. The organic methods used also provide security through improved genetic diversity of crops.

The benefits for the communities these farms serve and the cities in which they reside are far reaching and will lead to a better quality of life for all urban dwellers. Each of us have the opportunity to engage with our food and where it comes from – that is the first step towards a full scale urban agriculture system. The tomatoes in the picture above were grown in my garden :)

In Cape Town Abalimi Bezekhaya (which means planters of the home) help to establish community gardens which improve food security and provide additional sustainable income to their tenders. Abalimi also has a number of greening projects which help to improve the living environment of impoverished communities. On Tuesday 26 May 2009 there is a tour of their operation which I will be going on. The tour begins at 09h00 in Wynberg and finishes at 12h00. Please let me know if you will be joining me.

Nature strives towards efficiency. Efficiency can be defined as any waste which occurs in achieving a goal, or, "The ratio of the effective or useful output to the total input in any system."

Efficiency is the perfect use of material. Packaging is inefficient, as the "goal" is what is inside the package, while the packaging becomes waste. Packaging can be efficient if it is reused, as it never exits the system. Recycling requires extra energy, and is therefore less efficient than reusing, but more efficient than throwing away packaging. Using less to achieve the same is material efficiency. Smaller products, less packaging, lower material consumption. Have you ever considered how you could design exactly the same thing but smaller? Electronic engineers, think about small 0402 or 0201 size resistors over larger ones – in most cases they are functionally equivalent, but use less material and require less space on a PCB.

Efficiency is the perfect use of fuel. Internal combustion engines are around 20% efficient – that means 80% of the energy you put into your car is wasted. If cars were 100% efficient they would have zero emmissions and generate no heat. Did you know that cycling is the most energy efficient mode of transport?

Efficiency is the perfect use of water. Polluting potable water with waste such as sewerage and chemical cleaners requires energy and further chemicals to restore the water to a usable state. Efficient water usage means reducing consumption and leaving it in a usable state. Reducing waste and chemicals entering the water system means more efficient processing of water. Processing waste on site (composting toilets, greywater systems) reduces both waste and water consumption.

Solar energy is time efficient. Oil and natural gasses are the result of thousands of years of energy from the sun. Using the sun directly is an efficient time short cut.

Increasing crop yields makes more efficient use of space. Decreasing the use of fertilizers moves towards the perfect balance of an efficient ecosystem. Growing food near where it will be consumed is transport efficient. All our environmental goals centre around efficiency.

We need to learn from nature – waste nothing, strive towards perfect efficiency.