Designing Sustainable Small Farms

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ALTERNATIVE TECHNOLOGIES

Solar, wind, and other alternative technologies are also considered in permaculture plans. Options for the small farm or homestead include solar water heaters, photovoltaic systems, solar greenhouses, wind machines, methane digesters, and small hydroelectric setups, to name a few. In choosing design components, always look first for structures and systems that save or generate energy, and only then consider those that consume energy.

Of course, even solar technologies use nonrenewable energy during their manufacture. However, a fossil fuel can be viewed either as an inoculant or as an addiction. The embodied petroleum fuels in greenhouse glazing, for example, create a biologically powered environment that, over its useful lifetime, will repay that initial energy investment many times. Fossil energy invested in automobiles, in contrast, requires ongoing fuel investments in order to serve the desired functions. That's addiction.

The same distinction can be applied to soil restoration. Soluble fertilizers applied once to worn-out, eroded soil will produce a green manure crop that's high in biomass, which in turn supplies organic matter for biologically derived fertility. In this instance, the fertilizer acts as an inoculant. Conventional farming, on the other hand, is addicted to soluble fertilizers, using them as ongoing replacements for biological fertility.

SUCCESSION

A good permaculture design also takes advantage of the fact that landscapes develop over time. Orchard trees mature, weed and insect populations change, and woodlot composition shifts. In natural ecosystems, this concept is known as succession ... and it describes the process by which, for example, an abandoned field becomes inhabited with successive communities of weeds, wildflowers, shrubs, pioneer trees, and mature species until it becomes a forest.

In conventional farming, succession is frozen at an early stage by practices such as tillage, grazing, fertilizing, and pest control ... all of which require energy-in the form of human labor and chemical fertilizers and pesticides-for operation. By allowing agricultural succession to occur, or even by consciously directing it, energy and nutrients can be conserved, soil losses reduced, and herbivore populations stabilized.

Simple successional systems also make economic sense. For example, annuals and short-lived perennials planted between the rows of a young orchard will furnish income while the orchard species mature. Photo 9 illustrates a system incorporating beans, plums, and walnut trees. The beans and plums will eventually be shaded out by the final crop, walnuts.

In some cases, understanding the successional process provides the clue to optimal land use. Many shrub communities actually create the environment for the succeeding tree species. Trees that follow pioneer species in a successional series, for instance, are often shade tolerant and, in fact, require a shaded environment for germination. Other pioneer species are nitrogen fixers. By building up the soil nitrogen level, these plants create a more fertile soil in which succeeding species can thrive. Such communities could be interplanted with desired trees to accelerate succession.

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