For several years, biodiversity has been the major buzzword among conservation biologists as measures of diversity are commonly used as indicators of the condition of ecological systems. Such books as Olson et al. (1995) demonstrate that the concept of diversity is beginning to find significant applications in U.S. agriculture, too. Diversity is widely thought to be a beneficial, even essential, property of healthy biological, social, and economic systems, and agriculture intersects the realms of all three.
Many of the environmental problems associated with industrialized agriculture arise from the monoculture mind-set. Perennial grain polyculture, as a component of a diversified farming operation, could simultaneously produce significant amounts of grain while providing the benefits of soil and water conservation currently achieved through the CRP. It would enhance the long-term viability of agriculture by providing food without exhausting or contaminating the natural resource base upon which productivity depends. Perennial grain fields could provide an alternative to the CRP, increase year-to-year predictability, and allow greater within-season flexibility (i.e., provide grain, hay, or pasture). In exploring this paradigm shift from annual grain monoculture to perennial grain fields as analogs of natural grassland ecosystems, we acknowledge that the work is inherently long term and transdisciplinary.
The grain varieties that would be grown in perennial polyculture do not yet exist. Thus, a long-term domestication process is required. Because we may not see great progress for a few years, such an endeavor requires great patience on the parts of both scientists and funding agencies. Moreover, because perennial grains will be required to maintain themselves in the field for a period of years instead of months as with annual crops, it is necessary to incorporate multiple-year patterns of growth and seed yield into crop development research. For example, will yields be predictable year to year, or will they oscillate wildly? How will interactions among crop species in polyculture change over years? Unlike the grower of annual crops, who has some flexibility in changing crops after each growing season, the grower of perennial polyculture will have to project over several possibly very different growing seasons.
The work is also necessarily interdisciplinary and cooperative, not only within the plant sciences but among the plant sciences and other sciences, as well as among the "hard" sciences and the social sciences. It is, therefore, going to require a great deal of cooperation among people who previously may not have interacted much outside their areas of expertise. A research team to explore natural systems agriculture would include one or more ecologists, including those who specialize in crop-weed interactions, soils, insects, and plant pathogens. Several plant breeders would be needed to focus on perennial grasses, legumes, and composites. The crop development and ecological research would be aided by scientists with expertise in biotechnology and computer modeling. An environmental historian would put the work in context. This list is by no means exhaustive, and several additions are likely.
The work at this point remains somewhat risky both in terms of satisfying funders seeking short-term payoffs as well as for professional advancement (Soule and Piper, 1992). As we continue to deplete our soils and contaminate the environment, however, the long-term riskiest path for agriculture may well be the one we are on at present. Perennial grain agriculture represents a largely unexplored approach that will provide new avenues and insights for agricultural researchers and other scientists. Innovative and creative alternatives, however, are likely to provide the greatest insights and discoveries within science.
Humanity's utter dependence upon a thin layer of active soil is summed up in "Albrecht's dilemma," named after Missouri soil scientist William A. Albrecht. To feed ourselves, we appropriate nature's bounty by plowing up the prairie soil, planting crops which produce more useful food than could be obtained from the wild, but in the process accelerate the loss of nutrients from the soil. The movement of productive soil from the land to the sea is hastened, to our peril, by this necessary human activity. Opie (1993) has stated that Albrecht's dilemma is in essence an ethical paradox facing humanity and the environment. It is the conflict between the inevitability of soil destruction by farming and the imperative of soil protection to ensure a continued food supply. Most approaches toward a sustainable agriculture can at best reduce somewhat the present environmental problems created by modern agricultural production. Natural systems agriculture, in contrast, offers the possibility of achieving ecological restoration as a consequence of agricultural production. Studies of experimental grassland systems are showing that diversity, productivity, and sustainability can go together (Tilman et al., 1996). The question facing us is whether the tragedy of soil loss will be allowed to continue or whether the natural systems approach will be explored as a means of reconciling the two priorities of food production and preserving our ecological capital.
A perennial polyculture of grains is really a "domesticated prairie." It is admittedly a radical departure from current agriculture. It involves new crop species, selected under much more complex regimes than are used for crops destined for monoculture, and new designs for crop mixtures. Novel approaches toward a sustainable agriculture highlight the critical importance of maintaining biodiversity. Efforts to safeguard wild species, and the ecosystems that contain them, are necessary to provide humanity with the widest possible range of options for the domestication of perennial grains. The principles discovered along the way are likely to be applicable across an array of agroecosystem types. Thus, in the work to create a natural systems agriculture much new research ground must be broken, but in the process, it is hoped, the broken ground of the prairie will begin to be healed.
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