Good crop management practice includes soil and seed bed preparation. “The goal should be to achieve a firm seed bed with minimum moisture loss. It is also important to distribute crop residues,” said John Swanson, Federated agronomist at the Ogilvie location.
Unevenly distributed crop residue contributes to uneven soil temperatures and moisture levels, and those variations in the seed bed inhibit good seed-to-soil contact. The goal should be “to minimize the variability . . . to get crops off to a good start,” he said.
Then, with a prepared seedbed, “planting depth in corn is very important,” he said, and the only way to ensure the proper depth is to adjust the planter before hitting the fields, and whenever soil types or planting conditions change. Swanson noted these specifics for corn planting depths:
- - 2 in. is optimal in most situations in central MN and western WI.
- - 1.75 in. is recommended for really tight clay soils.
- - 2.25 in. is beneficial in really sandy soils.
Agronomists often say it’s better to error deep on planting rather than shallow because “shallow [corn] seed placement increases the risk of poor nodal root establishment,” said Swanson. He went on to explain why:
- “The mesocotyl is the portion of the corn shoot below ground between the seed and the crown of the plant. The crown is the base of the corn plant from which the permanent roots grow. We need to be sure we are planting deep enough, or the roots develop too close to the surface and we can end up with what is known as rootless corn. This is the condition where the permanent or secondary roots do not grow from the crown and we have standability issues because we don’t have the necessary roots for proper support.”
Soybeans require adequate soil moisture levels for good emergence, so proper planting depth is essential. Soybean planting depths generally fall at 1-1.5 inches, but:
- - plant on the shallower end for high-residue conditions, fine-textured (heavy) soils, and moist soils,
- - plant on the deeper end of the range – up to 2 in. – in course-textured (sandy) soils and dry soil conditions.
Swanson noted that for planting depths greater than 1.5 in., “it is critical . . . to have a soybean with a great emergence score.”
The only way to ensure proper planting depth is to consistently check and adjust the planter. Don’t just “set it once and go,” said Swanson. And, be sure to talk to your Federated Agronomist with any questions about planting depth.