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Surprising Sustainability of Great Plains Agriculture
22 Nov, 2007 11:01 am
A century-long examination of trends in population, farm income and crop production in the Great Plains reveals stability of farm income and population during the last 40 years, while simultaneously revealing large increases in crop yields.
The study shows that the region is not homogeneous, with different experiences in three broad categories of counties: those with metropolitan cities, those with rural populations and irrigated agriculture, and those with rural populations but without irrigated agriculture. Metropolitan counties grew rapidly in the Great Plains during the past 75 years, just as they have elsewhere in the US. The rural population decreased from the 1930ís until the 1960ís, but has apparently in rural non-irrigated regions and increased slightly in regions with access to irrigation water. Aging of the population has increasedmore rapidly in the rural non-urban counties with the highest percentage of the population greater than 65 years old in the dryland nonmetro region, followed by the irrigated non Ėmetro and metro regions. Crop production of corn, wheat, and cotton has increased substantially (100 to 300 %) since the 1950s as a result of increased inputs of nitrogen fertilizer, improved crop varieties, advanced soil tillage practices, and increased use of irrigation. The increased production of corn from irrigated agriculture has led to a big increase in animal production during the last 50 years. In turn, much of the increase in gross farm income during the last 50 years has resulted from increased animal production. The underlying increase in irrigated crop production has been associated with negative environmental trends, especially NO3 leaching into groundwater and increased emission of greenhouse gases (primarily N2O). The increase in production was not uniform across the region. In contrast with the irrigated rural counties, data from the Urban counties show a substantial reduction in farmland acres and gross farm income associated with animal production since the 1960ís. In other words, population growth in urban counties has had a negative impact on agriculture in those counties, while increased irrigation in rural irrigated counties has increased crop and animal production, gross farm income, and stabilized population. Gross farm income has decreased somewhat and population has stabilized since the 1970ís for the non-irrigated rural counties.
Net farm income during the last 50 years has remained surprisingly stable and is a result of contrasting long term trends. Crop yields and animal production has increased dramatically, while the ratio of purchased inputs to gross farm income has increased thus reducing net farm income. The other important long term trend has been the dramatic increase in direct government payments to farmers with over 50% of the net income coming from government payment during the last 10years. The recent dramatic increases in energy costs is a concern since this will result in increased expenses to irrigate the land and fertilize crops. Another concern is the increased competition for irrigation water from Urban regions and lowering of the ground water levels in Ogallala Aquifer. Growing demand for grain can increase profits for farmers and produce work that will add to population. At the same time, agriculture on the Great Plains uses a large amount of energy for irrigation and equipment, and energy prices drive up the cost of fertilizer. It not yet possible to see how well farmers, their employees and neighbors will do in the changing environment of rising prices for the energy they consume and the food and fiber they produce.
This study of long-term trends suggests that many of the potential threats to the Great Plains that have worried the local population, scientists and policy makers may be less significant in a long-term context than they appear at any given moment. Nevertheless the regionís reliance on agriculture, the variability of the weather, the increasing requirements of modern agriculture for water and energy, and the ever-changing demands of the market mean that nothing is ever settled in the region. More change may always be just around the corner.
1. William J. Parton, Myron P. Gutmann, and Dennis Ojima. Long-Term Trends in Population, Farm Income, and Crop Production in the Great Plains. BioScience, October 2007.