Drive around the state and you'll see plenty of cornfields that are absolutely gorgeous. Stands are nice, plants are a deep green color and the root systems look really good.
The corn looks considerably better than the beans. "It's been a good planting season for corn in most of Illinois and a less favorable one for soybean, with cool, damp weather in mid-May and conditions ranging from too dry to too wet," observes Emerson Nafziger, a University of Illinois agronomist. "Soybean replanting percentages were much higher than normal in some areas. About the only positive part of this is that replanted soybeans have ended up not too far behind fields that were not replanted, as the latter struggled with the weather and soil conditions."
Over the next couple weeks, the corn canopy will complete its growth. Canopy formation is a critical process that sets the stage for successful flowering and grain filling. In corn, canopy closure is when nearly all of the sunlight is falling on leaves, rather than some getting through to the soil. With 30-inch rows, the canopy appears to close when the crop is about 30 to 36 inches tall.
"Roots are also viewed as critical to the success of vegetative development, and rightly so," says Nafziger. "As we found out during the very dry June in 2005, a good root system is capable of maintaining a good supply of water to the plant almost completely from the water stored in the soil.
"We think that dry June weather is often very helpful in helping roots reach their maximum effectiveness. This is both because fewer diseases develop when surface soils are dry and because dry surface soils mean less root growth near the surface but increased root growth deeper in the soil where there is more water available.
"Healthy root systems do a great deal to reduce stress during pollination, which in turn goes a long way in setting the course for high yields," he adds. "So far in 2006, the corn crop is doing quite well on both ends (tops and roots), and we hope this balance can continue. As water movement through plants continues to build along with the canopy, though, demands on soil water will start to deplete that supply, and we will need some rainfall to make up the difference. Few areas in Illinois are critical yet, but water loss rates are approaching an inch per week now, and most soils will need some help from rain within the next three weeks if maximum crop growth rates are to be maintained," Nafziger says.