By Mark Licht and Sotirios Archontoulis– Iowa State University Extension and Outreach
Spring rains led to late planting and now cooler temperatures in June are further complicating this year’s growing season across the Midwest. A tool developed by Iowa State University Department of Agronomy researchers offers farmers important data to help them make decisions, including nitrogen applications in the coming weeks.
“The tool integrates and converts weather, soil, and management data into agronomic variables of importance to support decision making,” said Sotirios Archontoulis, associate professor of agronomy at Iowa State. “Combining weather information with data about soil water and soil nitrogen makes the tool an agronomic powerhouse for farmers.”
The Forecast and Assessment of Cropping sysTemS (FACTS) project was first launched in 2015 to provide yield and soil nitrogen predictions in Iowa at a field scale. In 2019 the tool expanded from 10 Iowa fields to 7,000 fields across the I-states. The project is the first of its kind to add a regional scale to include coverage for Illinois and Indiana.
Weather data from the Iowa Environmental Mesonet, soil information from the USDA Natural Resources Conservation Service, and management information from the USDA National Agricultural Statistics Service and local experts all feed into a single program that quickly analyzes the information to offer meaningful agronomic information.
Precipitation is important, but the reason it matters is soil moisture, which varies by soil type. That moisture drives nitrogen loss. By combining moisture and soil nitrogen mineralization data, farmers have more information to make decisions about additional nitrogen application in the coming weeks.
Soil water and soil nitrogen are presented as indexes meaning optimum is as close to one as possible. Below normal values fall below one and above normal over one. These indexes are updated every Wednesday.
“This type of information is timely considering the impact weather has had on planting across the I-states,” said Mark Licht, assistant professor and extension specialist at Iowa State. “The next issue is how the rainfall will affect nitrogen availability for a rapidly growing crop.”
Specific data includes showing precipitation and growing degree days in two forms; cumulative since May 1st to present and a seven-day forecast. FACTS updates this daily at 9:00 am.
Future improvements to the tool are already in the works. Additional variables like crop nitrogen uptake rates, grain yield accumulation, root depth, and end of season yield predictions for both corn and soybeans will be added.
The project is made possible by support from the Iowa Soybean Association, the Foundation for Food and Agriculture Research, the Iowa Crop Improvement Association, the National Science Foundation, the Plant Sciences Institute, Iowa State University Agriculture and Natural Resources Extension and Outreach, and the APSIM Initiative.