What is in this article?:
• On May 29, Georgia corn producers reported that 27 percent of the crop was fair, 49 percent good, and 20 percent was in excellent condition. In Alabama, 27 percent was fair, 63 percent good, and 8 percent excellent.
• Now, it’s up to producers to help finish out the crop, and this is where irrigation strategies become important.
HEADING INTO THE critical month of June, many corn producers in the lower Southeast were reporting excellent crops despite a relatively dry spring this year.
Keep plant moving
“If you’re going through that type of drought, use one of your irrigations during that time to make sure you keep plant development moving. Water again at tasseling and then at blister and early grain fill.”
Producers need to take a more holistic approach to corn irrigation, says Lee.
“One of the important things is getting water to the crop area and to the crop area only. With today’s technology, we can use end-guns to expand the pivot or area and also to cut it off when we get towards roadways and other areas that don’t need water,” he says.
Lee says it’s troubling to see center pivots in parts of Georgia and Alabama that cover 150 to 200 acres.
“Whenever we have that many towers, it’s important that we don’t put that full pivot strictly over corn. We need other crops under there because the critical water demand period for corn is going to be earlier than that for cotton, peanuts or soybeans. By splitting it, you can apply water on corn early and often and not be limited by your application and application efficiency.”
Growers today have access to shut-off technology for extremely wet areas and they have variable-rate technology, notes Lee. These can be important in minimizing drip and evaporation. Some producers also are using subsurface drip irrigation tape, especially for irregular-shaped fields.
“The question is whether or not subsurface drip is good enough to use in multiple years. We’re exploring that now, and the jury is still out. If you’re a dryland producer, I think we can smooth out some of that variability from year to year with drip tape.”
With subsurface drip irrigation, there are no drip or spray losses, and 100 percent of the water gets into the soil, he says. However, the leaching capacity is greater, and you don’t get a wet surface.
“So you can’t use subsurface drip to get germination, to activate herbicides, or to dissolve fertilizer, and that’s the disadvantage. The advantage is that it’s highly efficient and be used in irregular-shaped fields. But if you place it too deep, you reduce the impact on your water and your yield.”
It’s important, says Lee, that growers get water into the root zone and not behind it. “There are new devices that can help you understand water use in the ground and prevent you from allowing the subsoil moisture to become dry. They maximize irrigation and water use efficiency.
“The prices of some of these tools are declining. They help us just as a tool, and we can use them in different soil types to help us become very efficient in how we water our crop.”