food sustainability

Integrated farming systems for sustainable food

There was a great article in the Guardian this week about integrated urban farming in Germany. I thought I’d follow it up, as integrated farming systems are one of the ways to raise food production for a growing population without increasing ecological damage.

The example featured was from a German company called Efficient City Farming, which designs and supplies aquaponic systems for the urban environment. Their container farm is a small closed-loop agricultural unit that produces vegetables, herbs and fish. It’s made from a repurposed shipping container which serves as a fish tank, with a greenhouse on top. Normally fish farming causes quite serious pollutions problems, but here it is turned into an advantage. Ammonia excreted by the fish is filtered and used as fertiliser for the plants, the water recycled through from the tank to the greenhouse and back again. The system saves CO2 and water, and is small enough to be placed on rooftops, in car parks or in back gardens. The company intends to sell them to restaurants to encourage local food production.

The container farm is obviously small-scale and is rather expensive, so its value is probably more to do with championing integrated farming systems than actually producing sustainable food. It takes quite ancient ideas and bundles them with modern technology to create a simple and iconic demonstration of sustainable farming. It is these sorts of input/output loops that will be key to making agriculture more sustainable over the next century.

If you grow vegetables in any serious way, you already understand the joys of creating your own compost and recycling garden waste into next year’s growth. Permaculturalists know about keeping chickens or ducks for their droppings, and Masanobu Fukuoka famously used rice straw to mulch barley, then barley straw to mulch his rice in alternate seasons. Traditional Chinese agriculture uses the silt from fish ponds as a source or fertiliser, and of course the traditional British farm mixes lifestock and horticulture.

This is how integrated farming works, by looking for multiple, synergistic outputs. Adding meat production to the farm opens up a host of possibilities, using pigs, chickens, or vegetarian fish such as tilapia to consume the waste products from plant crops. You can also factor in energy use, looking for positive loops by growing biofuels or biogas for use on the farm, and water use.

These sorts of beneficial relationships are not difficult at the garden or allotment level, or even for small traditional farms. Farms today are bigger than ever, and at larger scales it’s easier to take the industrial shortcuts of chemical fertiliser and diesel-powered mechanisation. That raises yields and profits, but at the expense of soil fertility. One of the challenges of farming in the 21st century is scaling up integrated farming techniques to meet the needs of larger farms, resisting the trend towards monoculture and specialisation.

It’s a challenge worth supporting through research and investment. Integrated farming lowers costs on feed, fertiliser and energy, while diversifying income streams and increasing output. It would reduce dependency on fossil fuels and lower CO2, making agriculture more sustainable without raising food prices. In countries with recurring famines, sharing best practice or new techniques for small farmers could be an important way of improving diets – the charity Practical Action recommends raising small fish in rice fields, for example.

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