Abstracts

Nearly all of nature's land-based ecosystems feature perennial mixtures, be they rainforests, deciduous forests, prairie meadows, and most others. Grain agriculture reversed the perennial habit and when grown in monocultures reversed the dominant reality of perennial diversity. This is not trivial since annual monocultures of grains and oilseeds are responsible for some 70 percent of our food calories grown on 70 percent of our global agricultural acreage. With perennial grain crops on the horizon, a new set of agricultural practices is bound to follow. Farmers will have help from renewable sources to deal with ancient forces like gravity, which takes topsoil, and drought, flooding and competition, which threaten crops. In late industrial time the response to such forces has featured, in addition to improved varieties, commercial fertilizer, pesticides, fossil fuel powered equipment, and irrigation. We can now imagine practices changing. Problems can be addressed by referring to natural ecosystems, which feature material recycling and run on contemporary sunlight, with little deficit spending of ecological capital.

With perennial grains we can imagine grain mixtures and a broad array of processes-largely confined to wild nature now-brought to the grain producing field. Grain farmers can one day use the most effective of all means to stop soil erosion: perennial roots. The threat posed to food production by drought and flooding will be reduced. With the protection offered by a healthy ecosystem, pathogens and invertebrate pests will be managed without poisoning the landscape.

Beyond perennial grains, we need ecology. To achieve sustainable nutrient management, stabilize or prevent insect and disease damage, optimize water use, take advantage of species differences in growth period and ensure other important features of low-input farming will require agriculturists to be mindful of natural ecosystems as they assemble perennial polycultures. Thankfully, the various principles of ecosystem function already discovered in studies of nature's grasslands and elsewhere, are available for adoption.