As many cornfields transition away from the seedling stage they might start to show uneven growth patterns and become very erratic in appearance. This phenomenon has been referred to as the ‘ugly’ or ‘roller coaster’ stage of corn growth.
What causes many fields to exhibit this variable growth or color pattern during this time?
The young corn seedling relies on the nourishment of the food reserves in the seed until V1 or V2, which is when the nodal roots start to become visible. Until this point the seminal roots or seed root have provided mainly moisture to the young plant. Once the nodal roots begin developing around the V3 stage, the plant relies on the nodal roots to take over and supply the required fertility to grow.
It is right around this stage that the roller coaster ride often begins in a corn field. At this V3 stage the nodal roots should be tapping into starter fertilizer, but if anything has damaged or delayed the roots big differences can be observed. Things like a smeared seed wall, root-feeding insects such as grubs, or even hot/dry soils that can inhibit root bud elongation will begin to take their toll on the uniformity of the stand.
Even in the absence of a starter application, anything that limits the growth of the nodal roots at this critical transition can cause that uneven growth. In many cases the additional stress can also lead to color changes such as purpling, striping or white blotches. There are many explanations for these color changes, but they are often associated with this critical phase of root system transition. Often times the field is a mirror reflection of past sins that will show up at this critical time, such as harvesting in wet conditions in the fall.
Although it can be tough to look at a field as it grows through this stage, often times the nodal roots are able to get going and start supplying the plant with nutrition and moisture. The corn begins to ‘straighten out’ and recover from whatever factor was limiting its growth. If the unevenness continues, a walk with your favorite agronomist would be time well spent to help diagnose the issue in order to avoid it again in the future.
Photo courtesy of Integrated Crop Management News