In recent years, producers in the Corn Belt have experienced the extremes in weather and crop yields. Following the devastating 2012 drought, corn yields were the worst in 30 years. Two years later, yields reached all-time highs in Nebraska. Facing such variability, corn producers and agribusiness have looked to the Yield Forecast Center developed at the University of Nebraska-Lincoln for accurate corn yield predictions to help guide in-season decision-making.

RECORD YIELDS NOT LIKELY: The Yield Forecast Center developed at the University of Nebraska–Lincoln provides producers with accurate corn yield predictions. According to Patricio Grassini, the UNL Yield Forecast Center is not seeing solid evidence of a record corn yield this year.

The biweekly model forecasts yield for 41 sites in 10 states across the Corn Belt, including Illinois, Indiana, Iowa, Kansas, Michigan, Missouri, Minnesota, Nebraska, North Dakota and Ohio. For each site the forecast considers over 20 years of historical yield data on yield, soil property, water regime and crop maturity, as well as current data on solar radiation, minimum and maximum air temperatures, rainfall, and plant evapotranspiration.

Patricio Grassini, assistant professor in the Department of Agronomy and Horticulture, started releasing corn yield forecasts in 2011. He initially focused on four sites in Nebraska before taking his model to sites in Iowa and Illinois. As the in-season forecasts proved accurate when compared to end-of-season actual harvest yields and the demand for the forecasts grew, Grassini formalized the Yield Forecast Center, and built a team of faculty and Extension educators from across 10 universities. The approach to forecast corn yield consists of robust simulations that capture the influence of weather, soil and management, together with a spatial framework.

A journal publication describing the Yield Forecast Center approach has been recently published in the international, peer-reviewed Field Crops Research journal.

Another yield forecast is distributed by the USDA National Agricultural Statistics Service. NASS predicts crop yields by state on a monthly basis. According to that model, corn producers are expected to harvest a record crop this year, which slightly differs from what the UNL Yield Forecast Center projects for 2016.

According to Grassini, the UNL Yield Forecast Center is not seeing solid evidence of a record corn yield this year. The model currently projects a yield slightly above average, but not a definitive record crop. Despite the differences in the forecast, Grassini views the UNL model as complementary to the NASS forecast model.

"Our approach can help develop forecasts at a higher level of spatial and temporal resolution, and provide a probability associated with each forecast instead of a single figure for each state once a month as currently provided by USDA NASS," said Grassini.

As of Sept. 2, the UNL hybrid-maize model is forecasting 200 bushels of corn per acre for irrigated cropland in Nebraska, a yield slightly higher than average. For rain-fed cropland, the model is forecasting 151 bushels of corn per acre, also higher than average. Both of these forecasts are lower than the historical record yield.

A significant amount of data is collected to develop the yield forecasts. For each forecast, faculty and Extension educators from all partner universities provide input on their crop stage. Assisting Grassini to run the forecasts at UNL are Gonzalo Rizzo, a visiting scholar from the University of the Republica (Uruguay), and Juan Ignacio Rattalino Edreira, a UNL postdoctoral research associate. Others involved with the project in Nebraska include Ken Cassman, Emeritus Robert B. Daugherty professor in the Department of Agronomy and Horticulture; Roger Elmore, Extension cropping systems agronomist and professor in the Department of Agronomy and Horticulture; Keith Glewen and Jenny Rees, Extension educators; Charles Shapiro, professor in the Department of Agronomy and Horticulture; and Haishun Yang, associate professor in the Department of Agronomy and Horticulture.

Source: IANR News