Source: Crop Watch News Service
University of Nebraska Institute of Agriculture and Natural Resources Cooperative Extension

Hybrid-Maize is a user-friendly computer program that simulates the growth and yield of corn under non-limiting or water-limited (i.e. irrigated or rainfed) conditions based on daily weather data. This software is the result of a long-term interdisciplinary research program in the UNL Department of Agronomy and Horticulture to understand corn and soybean yield potential. The purpose of this simulation model is to allow maize producers, crop consultants, and researchers to hypothetically explore the impact of weather and management changes on crop performance so that they might better understand site yield potential, year-to-year variation in yield potential, and possible management options that affect yield and yield stability. As with all modern decision aids, Hybrid-Maize represents a simplification of the 'real-world' system and, as such, its predictions may differ from actual outcomes. So far, Hybrid-Maize has been evaluated primarily in rainfed and irrigated corn systems in the U.S. Corn Belt, where it has shown great potential for predicting corn growth and yields.

Hybrid-Maize allows users to:

• assess the overall site yield potential and its variability based on historical weather data;
• evaluate how different combinations of planting date, hybrid maturity, and plant density can change the attainable yield;
• analyze corn yield in relation to the timing of silking and maturity in specific years;
• explore options for optimal irrigation management; and
• conduct in-season simulations to evaluate actual growth up to the current date based on real- time weather data, and to forecast final yield scenarios based on historical weather data for the remainder of the growing season. Use these predictions to make adjustments in irrigation and nitrogen management.

The software does not yet allow assessment of different options for nutrient management nor does it account for yield losses due to weeds, insects, diseases, lodging, and other stresses. Hybrid- Maize allows utilizing real-time and long-term weather that are available to many producers in Nebraska through the online subscription services of the High Plains Regional Climate Center. Through the HPRRC, daily weather data can be directly accessed for numerous locations in Nebraska and neighboring states (see a map of locations at (http://www.hprcc.unl.edu/awdn/awdn_station_loc.html).

For more information visit the Hybrid-Maize Model Web or email Haishun Yang, one of the project authors, at hyang2@unl.edu.

University of Nebraska-Lincoln news release

A user-friendly computer program that simulates corn growth and yields to help producers make better management decisions now is available from the University of Nebraska-Lincoln.

The simulation software, called Hybrid-Maize, combines field-specific information with historical weather data and planting information to predict crop yields. Users essentially can play "what if" by changing variables to see how weather or management changes influence crop performance.

The software is the result of ongoing interdisciplinary research to better understand corn and soybean yield potential, said Soil Scientist Achim Dobermann, who helped develop the program in collaboration with agronomy and horticulture department colleagues Haishun Yang, Ken Cassman, Dan Walters and other Institute of Agriculture and Natural Resources agricultural scientists.

Hybrid-Maize lets producers, crop consultants and researchers use current and historical weather information along with field-specific details to experiment with various corn production factors including planting dates, rainfall or irrigation, fertilizer rates, soil types, hybrid selection and plant density. These predictions can help corn growers adjust irrigation and nitrogen applications to boost profits.

"Producers can use the software to evaluate growth at any time during the season and forecast final yields based on factors such as historical weather data and past crop performance," Dobermann said. "These predictions are particularly useful in drought conditions because this allows producers to make informed adjustments on irrigation and other crop inputs."

In the longer term, the software should help users better understand a field's yield potential, year-to-year yield variations and how different management schemes might affect crop performance.

The software has been tested primarily in dryland and irrigated corn production areas of the nation's Corn Belt.
Dobermann stressed that the software, like all simulation models, represents a simplification of an actual cropping system. It does not yet allow assessment of different fertilizer management options, nor does it account for yield losses due to weeds, insects, disease and other stresses. However, the software's ability to combine real-time and long-term weather data will make it an effective new tool.

Cassman said the Hybrid-Maize software is a major step forward in helping producers and professionals improve crop management and profits while also protecting the environment.

"It is becoming increasingly difficult to develop management guidelines for crop production," he said. "Today we need to consider not only productivity issues but also environmental concerns such as water quality and greenhouse gas emissions."

Producers traditionally have to monitor multiple sites over multiple years to develop a crop management plan, but even five years of data cannot cover all variations in climate patterns that occur over time, Cassman said. A simulation model helps juggle more variables and could be operated by the producers themselves.

"Hybrid-Maize is the beginning of something transformational in applied research because it can evaluate a range of management scenarios and assess risks and benefits that incorporate a number of complex, interactive factors, including more than 20 years of weather data at some sites," he said. "It will be a tremendous tool to develop management scenarios for producers at various locations."

The Hybrid-Maize software is paired with the Expanded Weather Database, created by the High Plains Regional Climate Center based at UNL to provide daily and historical weather data. Current weather data for a particular site can be downloaded from the climate center's Automated Weather Data Network. Software users can edit the weather data file by adding their own rainfall totals.

A free demonstration version of Nebraska Cooperative Extension's Hybrid-Maize software is available on the Web at http://www.hybridmaize.unl.edu. A full version is sold as an online download for $35 or as a CD-ROM bundled with the Expanded Weather Database for $60 at http://estore.adec.edu/. A CD-ROM version without the Expanded Weather Database is available for $40 from Nebraska Cooperative Extension offices statewide or by mail at Publications, Room 105, Agricultural Communications Building, P.O. Box 830918, Lincoln, NE 68583-0918. Those ordering by mail should ask for item "CD-9 Hybrid Maize" and can either request an invoice or send a $40 check payable to the University of Nebraska.

The weather database is also available separately by online subscription at http://www.hprcc.unl.edu/data.htm. The Hybrid-Maize research was conducted in cooperation with IANR's Agricultural Research Division with grants from the Nebraska Corn Board, the Fluid Fertilizer Foundation, the Consortium for Agricultural Soil Mitigation of Greenhouse Gases funded by U.S. Department of Agriculture, the Phosphate and Potash Institute, and the Foundation for Agronomic Research. The High Plains Regional Climate Center provided the historical weather data included in the model.