For those with incredibly short memories, Arkansas' 2005 growing season was a dry one. “Corn producers were watering here, watering there, watering as fast as they could,” said Jason Kelley, Arkansas Extension corn and wheat specialist. “For a while, that's all they seemed to be doing. Even so, a lot of times, they couldn't keep up.”
Many of the state's corn fields were watered 10 to 12 times. When irrigating that much, especially on soils that tend to seal over, “the water can flush through and come out the end without doing its job well,” Kelley told those attending the Yell County corn production meeting outside Dardanelle, Ark. “The row middles can still be dry. That's where a lot of producers got into trouble — the water just wasn't penetrating the soil well.”
Kelley also addressed the question of when to shut irrigation off. His advice: don't look to “dent” as the key indicator.
“It used to be when corn reached dent it was far enough along to shut the water off and not hurt yields. But dent is a relative term and, I think, in many situations, we ought to just throw it out. You can look at a corn cob and say, ‘Well, that looks at about dent.’ But you break the cob in half and the starch layer is just beginning to form.”
In many instances, a farmer will go to his corn field and say, “‘It's at dent and I've got beans and rice that need water. I'm shutting water off this corn because it's far enough along.’ Often, though, it isn't. If in doubt, go ahead and water it once more.”
If conditions are right — especially in the Arkansas River valley — some corn goes in the ground at the end of February. When that's the case, the seed can sit a long time — “maybe four, five, six weeks. If it's dry, I like to say March 10 to 15 should be your target planting date.”
This year, a lot of the early season hybrids, “especially on dryland corn, looked better. The water began running out quickly and the late-maturing hybrids just ran out of water. So on dryland, do your best to get in there early and get the crop made.”
One thing that's very critical is producers must do a good job of planting. “You want the plants equally spaced. Anything you can do to help with this, do.”
Some other crops can compensate for more ragged spacing. But once a corn field is planted, a large portion of the yield is already set.
“So it usually pays to slow down the planter a little. March is cold and we're in a hurry. The weatherman may be saying it's about to rain. But it's worth getting your spacing right.”
There has been increasing interest in twin-row planting, said Kelley. “Some producers are planting two rows of corn on one wide bed, usually on 38-inch spacing. The equipment companies are pushing this in some areas of the state.
“Data out of LSU, looking at two hybrids with different plant populations in this system, show very little benefit for corn. Twin row may be a good thing for soybeans but for corn, its benefits aren't really obvious.”
Currently, fields are dry and there's plenty of time to get soil samples taken. If deficiencies are found, “sulfur and zinc deficiencies need to be taken care of up front. Put them into a preplant fertilizer. In a bedded system, I usually like to put the fertilizer preplant and then bed it up. It gets the fertilizer set in that bed well.”
As for planting depth, “Many times in March we think, ‘well, the ground is cold and I don't think I should plant very deep.’ But for corn, that's the wrong approach. If you plant really shallow, the root system won't develop well.”
If you're on sandy soils, Kelley doesn't have a problem planting 2 inches deep. “If you're on really fine sand, you can probably go deeper than that. Corn will come up from that depth.”
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