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Dry soil this spring? Plant deep
Despite recent snowfall in the Corn Belt, soil moisture likely won't be up to its full potential in many parts of the region by the time planters roll.
But, all signs point to a serious need for a major corn crop this year. That means it'll be critical to get your planter adjusted so that you can get your crop off to the best possible start. If your soil's dry, that means planting a little deeper to get the seed closer to subsoil moisture, says Iowa State University Extension ag engineer Mark Hanna.
"Dry surface soil suggests deeper planting depths to obtain moisture for rapid germination. The seed depth adjustment on planters controls the distance between the bottom of the double-disc seed opener and bottom of depth-gauge wheels. Most planter row units have the ability to adjust this difference to at least 3 or 4 inches," he says. "Simply adjusting this depth difference between gauge wheels and seed opener, however, will not automatically mean seed is placed at the adjustment depth. A certain amount of weight or down force is required to push the seed opener into the soil before the adjacent depth wheel comes into contact with the surface. The down force required increases with increasing penetration depth. This is similar to increased force required to drive a spade deeper into the soil."
But, don't just think in terms of depth alone. Though it's important, it's just the first step. Make sure your row cleaners are also lowered, since they'll help place seed in a softer seedbed.
"Rather than relying strictly on depth adjustment between the bottom of the seed opener and bottom of depth-gauge wheels an alternative approach to increasing planting seed depth to a zone of adequate moisture is to create a furrow ahead of the planter by setting row cleaner depth deeper than usual," Hanna says. "This concept loosens soil for easier penetration of the seed opener."
Creating softer furrows for seed will also prevent damage from too much moisture if that happens to become a problem later in the spring.
"Rainfall can puddle and seal tilled soils affecting the ability of corn to emerge," Hanna says. "Even if corn has emerged, excessive water runoff erodes soil and can wash seed and plants from furrows if rows are sloping."