Tuesday 14 April 2009

Permaculture

Hear the word “farmland,” and you think of rows of crops – the same crops for acres of tilled flat land, a foot or two high, sown every spring and harvested every fall. This is what most farms look like today – tractors, straight lines, production maximized for efficiency.

Most of our food comes from farms like this, so perhaps we shouldn’t complain. But this model has its own limitations. Every year seeds must be saved, land tilled, weeds pulled and pests eradicated, so farming has been a laborious business. Each harvest yields a glut of food that must be preserved or processed to last the rest of the year. Farmland tends to be monoculture, scoured of trees and the cornucopia of plants and animals found in the wild.

Producing food this way works best on a grand scale, so farms have become ever larger, further removed from the experience of most people. Such methods require fossil fuels to run the tractors, make the pesticides and process the harvest into Cheesy Poofs. Farmers have been forced to find more and more creative ways to fend off the pests and diseases that evolve past our defences.

A glut of certain foods means the excess must be put to use somewhere else in the human economy, usually somewhere less healthy. Michael Pollan recently noted, for example, that most of Americans’ diet is actually corn -- grain fed to cattle for McDonalds, the sweetener in soda, the dextrose, starch, corn oil and many other foods.

And, while this is a side issue for the hungry, most farmland is not very pleasant to look at. Many people would fantasize a walk through the woods; few dream of walking through sorghum fields.

There is another approach, however: Permaculture, developed in the 1970s by Australians Bill Mollison and David Holmgren to replicate some of Nature’s diversity, but using plants and animals people can eat. Permaculturists generally prefer perennials, plants that do not need to be sown and harvested over and over, and strive to create a self-sustaining landscape that requires a minimum of maintenance.

Permaculture uses many different species together, treating them not as individual products but as components of a living system; for example, one plant might gain from nutrients its neighbour produces, or one plant might produce a scent that wards pests off the others.

The details depend on the climate and natural flora, but a good example is the forest garden. A permaculture grower might plant trees that produce nuts – according to Holmgren, a forest of walnut trees can produce as much food as the same acreage of wheat. Under the trees one can grow shade-loving plants, to create another layer of crops in the understory. Vines that produce berries can be trained to run up trunks and fences. Instead of simple fences or ornamental hedges, permaculturists prefer to use hedgerows that yield still more fruits, berries and edible leaves.

One of permaculture’s most basic principles is that gardens should require a minimum of input and generate no waste – vitals like water and nutrients should be used and re-used within the system. For example, Holmgren recommends keeping chickens inside a greenhouse if the weather is not too hot: the chickens keep warm inside, and in turn help keep the greenhouse warm with their body heat. They scratch through the soil, eat the young weeds and pests and their manure fertilizes the ground.

Mollison uses another example from his own land, when he needed more fertilizer: he planted berries across his roof, which not only provided food, beauty, shade and insulation, but attracted flocks of birds – which promptly fertilized everything in sight.

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