Harvest Shows Us How Planting Affects Corn

They say seeing is believing. This fall we’re seeing how planting depth affects emergence and root development, which consequently affects plant growth and ultimately impacts yield.

Last spring Latham’s Product Team shared a video recommending planting depth for corn in dry soils like many farmers across Latham Country were experiencing. In that video, we discussed how important it is to plant corn at a depth that allows the seed to be surrounded by moist soil. A planting depth of up to three inches allows excellent uniform emergence and allows for the corn plants nodal root system to develop properly.

The nodal root system is essentially the “radiator” that manages a corn plant’s health. By planting corn seed at a depth of 2¾ to 3 inches, you allow the nodal root system to be completely under the soil. This protects the entire root system from injury due to excessive heat, possible herbicide damage, and lack of moisture. Dry conditions throughout the 2021 growing season revealed some areas that showed the importance of this concept.

IMG 8760This photograph shows how roots and ears vary from a range of planting depths in one farmer’s field. Note the lack of health in the shallow planted roots and stalks as well as ear size differences when compared to the deeper planted seed. The 2¼ planting depth is less than our recommended 2¾ to 3 inches.Lyle planting depth photo

This cross-section photo shows a planting depth of 2 inches. Note the clear example of each of the 5 sets of nodal roots in the cross section. A depth of 2¾ would have protected the entire root system.

From the seat of your combine this fall, you might see issues with standability, plant health and ear size. Recall your planting conditions and consider how that might be affecting your results this fall. I carry a shovel from planting through harvest to assess the nodal root system of corn plants. Consider carrying a dirt shovel on the combine, so you can take a little time in trouble spots in your fields to assess what that roots system looks like. Stop in problem areas; dig up a few plants; and slice through the lower stalk and roots system for problems that might be from planting depth.

You might find stalk issues, and when you look further, you could find unhealthy nodal (crown) roots.  A diseased root system is usually the starting point for stalk rot issues; disease starts in roots and works its way up the stalk. You might find that root-lodged areas result from a lack of anchoring ability of shallower planted seeds.

Use what you learn from this fall to make adjustments next spring for greater crop performance in 2022.