The 2018 growing season is well underway. It is now time to start assessing the rewards of the spring planting season. Our first FACTS (Forecasting and Assessment of Cropping sysTemS) is now live for the 2018 growing season. There have been a couple of changes going into our fourth year. A field site at the ISU Northern and McNay Research and Demonstration farms have been added to increase geographic coverage. For each site only the ‘normal’ or treatment nearest ‘normal’ is included on the webpage to reduce complexity. Yield forecasts have been moved to the opening page of the Forecast Tool and relative yield values have been removed. We hope these changes make for a more meaningful user experience.
Highlights of the June 4 forecast
Soil nitrate-nitrogen is adequate to meet the increasing crop nitrogen requirement as corn rapidly increases both biomass and nitrogen uptake. Compared to 2016 and 2017, central Iowa corn planted on May 8 is 1.5 leaf stages further along resulting in 40% LAI (leaf area index) and 25% deeper rooting depth as of June 8; largely a result of greater accumulation of growing degree units from May 1 to June 8. In northern, because of later planting dates, there was less leaf development, LAI, and rooting depth gained. Whereas in southern Iowa where planting dates were slightly earlier, corn leaf development and LAI were slightly higher. Soybean growth and rooting depth generally followed the same results as corn with more leaf area and deeper roots in southern Iowa followed by central Iowa followed by northern Iowa.
Our analysis shows that the corn and soybean crop generally have a high yield potential even with the near record warm May experienced across the state. Across the state there is some variability in corn yields (approximately 265-205 bu/ac) compared to soybean yields (70-65 bu/ac). The forecast indicates that the highest soybean yields will occur from southwest to central (Kelley) Iowa while the lowest corn yields will be in south central and southeast Iowa.
Look for a new forecast in 7 to 10 days.