Nebraska Irrigated and Rainfed Corn Yield and Acreage Trends

• In 2017, irrigated and rainfed corn yields in Nebraska averaged 199.9 bu/ac and 147.2 bu/ac, respectively. The US average corn yield was 176.6 bu/ac.
• Nebraska irrigated corn yields are increasing at a rate of 2.169 bu/ac per year.
• Nebraska rainfed corn yields are also increasing, but at a slower rate of 1.759 bu/ac per year.
• US corn yields (mostly rainfed) are rising at a rate of 1.852 bu/ac year, which is not much more than the foregoing Nebraska rainfed corn rate.
• Large season-to-season fluctuations occur in rainfed corn yields because of annual variance in rainfall amounts and distribution.
• Irrigated corn yields are predictably high each year, so investing in yield-improving technological inputs is less risky and potentially more profitable.
• Such investments are likely why the yield difference between irrigated and rainfed corn production in Nebraska is widening on average by 0.41 (about 4/10) bu/ac per year.

Nebraska Irrigated and Rainfed Corn Acreage Trends

• In 2017, 5.278 million irrigated acres (56%) and 4.022 million rainfed acres (44%) of corn were grown in Nebraska.
• Since 2008 irrigated corn acreage has averaged about 5.5 million acres.
• Rainfed acreage, however, has doubled from about 2 million acres in the 1980s to about 4 million acres in the last five years.  
• It is of interest to note that the irrigated percentage of all corn acreage has declined from a high of 72% in 1981 to just 56% in 2017. This is primarily due to a doubling of rainfed corn acreage as well as a gradual replacement of continuous corn production with a soybean-corn rotation in many Nebraska irrigated fields.  
• The 2007 bump in irrigated corn acreage was due to a temporary shift of soybean acreage to corn acreage relative to producer anticipation in the spring of ethanol-driven higher corn prices.
• US corn production harvested area in 2017 was a record 89.5 million acres, up 8% from 2016.