Focus on Croplands in the Northern Plains

The Northern Plains region (Montana, Wyoming, Colorado, North Dakota, South Dakota, and Nebraska) has only 9% of the farms in the US, but 25% of the total US cropland. Included in this cropland is 26% of the US's irrigated lands. Major crops are corn (26% of US production), wheat (34% total, including 71% of the spring wheat and 72% of the durum wheat), and soybeans (16%). Other crops include oats (21% of US production), barley (51%), dry edible beans (56%), sunflower seed (86%) and sugarbeets (30%). In addition, the Northern Plains contains 37% of the US acres enrolled in Conservation Reserve, Wetlands Reserve, and Conservation Reserve Enhancement Programs. Recent trends showcase increasing corn and soybean acreage in eastern parts of the Northern Plains replacing wheat production and grasslands (Wright and Wimberly 2013). Croplands in the eastern parts of the Northern Plains are largely rainfed, where conservation efforts target strategies to reduce runoff. Irrigation for crops is highly prevalent in the middle portion of the Northern Plains due to the Ogallala aquifer. Possible concerns with irrigation from aquifers include vulnerability to pollution (Li and Merchant 2013), and reductions in aquifer recharge and depth, though these are much more pronounced in the Southern Great Plains. In the drier, western parts of the Northern Plains, most crops are grown under dryland conditions (e.g., wheat-fallow systems) often using no-till practices to reduce soil erosion (Hansen et al. 2012) or with irrigation from reservoirs fed from melting snow in mountains. Earlier snowmelt due to warmer temperatures and earlier onset of spring (Third National Climate Assessment, http://nca2014.globalchange.gov/) and less snow (due to more rain during the winter) present operational challenges for reservoir storage of water, and efficient use of this water. Furthermore, transfer of water from agricultural to urban use in metropolitan areas (e.g., Front Range of Colorado) has transformative consequences for croplands, as these lands will transfer from irrigated to dryland cropland production or to permanent vegetation cover. Predicted increases in temperatures and longer growing seasons (Third National Climate Assessment, http://nca2014.globalchange.gov/), can increase crop yields due to earlier planting, or decrease yields due to negative impacts during the critical grain-filling period (often due to high nighttime temperatures). Adaptation strategies for farmers for a changing climate are diverse including selection of genetics (varieties) specifically adapted to localized conditions, cover crops, precision planning of populations of crops, precision fertilization, precision watering/irrigation, crop sequencing within crop rotations, and direct seeding into stubble (Cutforth et al. 2007). Cutforth, H.W., S.M. McGinn, K.E. McPhee, and P.R. Miller. 2007. Adaptation of pulse crops to the changing climate of the Northern Great Plains. Agronomy 99: 1684-1999. Hansen, N.C., B.L. Allen, R.L. Baubhardt, and D.J. Lyon. 2012. Research achievements and adoption of no-till, dryland cropping in the semi-arid U.S. Great Plains. Field Crops Research 132:196-203. Li, R., and J.W. Merchant. 2013. Modeling vulnerability of groundwater to pollution under future scenarios of climate change and biofuels-related land use change: A case study in North Dakota, USA. Science of the Total Environment 447:32-45. Wright, C.K. and M.C. Wimberly. 2013. Recent land use change in the Western Corn Belt threatens grasslands and wetlands. Proceedings of the National Academy of Sciences 110:4134-4139.