To maintain human economic activity and quality of life in the Great Plains, it is essential to develop a strategy that efficiently uses and conserves natural resources over the long term. Agriculture provides the opportunity to use the water, soil, and other renewable resources of the Plains, but strategies and systems for crop, forage, and livestock production need to be designed for maximum sustainability. This means an agriculture that does not overly exploit or deplete these resources, an agriculture that is productive, economically sound, environmentally benign, and socially viable. One of the most successful models that meets these criteria, including maintaining rural communities, is a sustainable agriculture based on renewable resources, private farm ownership, and family farming units.
What defines the Plains climate for agriculture is a rate of evapotranspiration (water loss from soil and plants) that exceeds the rate of rainfall for an important part of the crop-growing season. There are many ways to compensate for this adverse climate, all involving capturing and storing moisture in the soil so that it will be available when crops are growing. They include reduced or zero tillage during land preparation, choosing crops that have low water needs, planting lower crop populations that will use less water, and managing weeds in a way that limits their water use. Application of chemical herbicides, coupled with minimum or zero tillage, can drastically reduce water loss from the soil surface, but there is the potential hazard of chemical contact by human applicators or nontarget members of the ecosystem. Woody perennial windbreaks can reduce transpiration from crops and increase production. A combination of these water-saving and harvesting methods makes maximum possible use of accumulated water storage from snow and rain.
Irrigation was long used in the Great Plains by Native Americans and later by European American immigrants who settled near rivers. There is now a large irrigated acreage in Nebraska, western Kansas, the Texas Panhandle, and southern Alberta. Although some acres depend on surface water supplies that are renewed each year, a large portion of irrigation in the Central and Southern Plains comes from the Ogallala Aquifer. During the past two decades this source of groundwater has been seriously depleted, especially in the Southern Plains. Farmers there have shifted from irrigated corn to less demanding crops such as grain sorghum and cotton. The Ogallala Aquifer is recharged through the Sandhills of Nebraska and from playa lakes on the Southern Plains, and thus can recuperate if irrigation is curtailed. Deeper aquifers below the Ogallala are composed of fossil water that, once depleted, is lost. Although irrigated production of cereals such as corn, grain sorghum, and wheat has been profitable over the past five decades, it is unlikely that production will continue, because Plains farmers have to compete with farmers farther east in the United States and in other countries with better rainfall conditions and much lower production costs. It is likely that scarce irrigation will be used only on specialty, higher-value crops in the future, hence the importance of sustainable agriculture.
Sustainable agriculture generally includes such production practices as crop rotation, integrated pest management, soil fertility that depends to the greatest extent possible on legumes and grasses in the sequence, and a minimum program of tillage that helps prevent soil erosion. Many proponents maintain that raising livestock as an integral component of the system is essential to long-term soil fertility and sustainability. Livestock provide a ready outlet for green forages and hay and speed the cycling of nutrients by consuming these forages and leaving manure in the fields. They also can graze crop residues in place, making use of such forages and cycling nutrients through manure. Composting animal manures and urban organic wastes is another method of returning important nutrients to the land and building soil organic matter. Although much of the nitrogen and some other elements are lost during the composting process, the nutrients are present in a more stable condition that makes them less susceptible to loss from the system after incorporation into the soil.
To be sustainable, an agricultural system must be economically viable in both the short term and the long term. Thus it is essential to design systems that enhance the resources on which productivity is based rather than pursuing a simplified system that exploits nonrenewable resources such as fossil fuels and sacrifices long-term sustainability for short-term gain. Federal price-support programs for specific crops distort the long-term biological and ecological realities, since farmers feel forced to seek monoculture strategies that maximize short-term gains. Likewise, short-term rental or lease agreements for land provide little incentive for the operator to conserve soil and focus on the future value of this resource. For these reasons, an agriculture based on family farm ownership and entrepreneurship seems the most likely to provide stability in food production and conservation of resources.
Social viability of rural communities is the final dimension of sustainable agriculture. When farms in the Great Plains were consolidated over the past century, the result was fewer people on the land as well as fewer in rural communities to provide support services and social infrastructure. Many small towns in the Plains have disappeared. In part this is a natural consequence of mechanization of agriculture, with fewer hands needed to till and harvest. It is also a result of improved transportation, since commodities can now be marketed over a wide area rather than depending on a local elevator or other buyer. On the business side, it is clear that the larger the farm the less the reliance on local services— pesticides, fertilizers, and equipment now may be purchased from a several state area rather than from the local dealer. The impact of large farms is loss of local business and consequently the loss of other rural infrastructure: churches, schools, medical facilities, entertainment, in short the loss of community. Such a system is clearly not sustainable from the family standpoint, and an agriculture that depends on distant ownership and minimumwage jobs does not promote conservation of natural or human resources. Building systems that add value to products locally, that generate both food and income for local residents, and that cycle dollars around in the community, rather than extracting them from the land and people, can lead to a more sustainable agriculture and food system for the Great Plains.
Charles A. Francis University of Nebraska-Lincoln
Edwards, Clive A., Rattan Lal, Patrick Madden, Robert H. Miller, and Gar House, eds. Sustainable Agricultural Systems. Ankeney IA: Soil and Water Conservation Society, 1990.
Francis, Charles A., Cornelia B. Flora, and Larry D. King. Sustainable Agriculture in Temperate Zones. New York: John Wiley & Sons, 1990.
Hegyes, Gabriel, and Charles Francis. Future Horizons: Recent Literature in Sustainable Agriculture. Lincoln: Center for Sustainable Agricultural Systems, University of Nebraska–Lincoln, 1997.