The Indiana Certified Crop Adviser panel includes Danny Greene, Greene Crop Consulting, Franklin; Brian Overstreet, soil conservation coordinator, Rensselaer; Dan Quinn, Purdue Extension corn specialist, West Lafayette; and Dan Ritter, Hoegemeyer Hybrids, Rensselaer.

 

The weather roller coaster early in the season meant that our corn emergence was across the board, resulting in many delayed emergers that never caught up. Did these plants act as weeds? How can we prevent them next year? Or if they pop up in these numbers again, how can we manage them?

 

Greene: The greater the difference in emergence timing, the more likely late-emerging corn plants are to act like weeds. Plants emerging behind their neighbors are at a competitive disadvantage for sunlight, water and nutrients. They typically develop thinner stalks and smaller ears, and severely delayed plants may produce little or no grain while continuing to compete with productive plants.

Prevention begins with the planter and soil conditions. Seed depth, downforce, residue management, seed-to-soil contact and furrow closure should be as consistent as possible. Sometimes, the best decision is simply waiting until soil conditions are fit to plant. Starter fertilizer may help early growth under cool or stressful conditions, but it won’t overcome poor seed placement or an inconsistent seedbed.

 

Once uneven emergence has occurred, there isn’t much you can do to make the late plants catch up. Evaluate the stand early to determine whether replanting is justified.

Overstreet: Delayed emergence of even just a day can reduce yields in corn. Placing seeds at the same depth, getting the seed slot closed uniformly and having the seed bed firmed properly around the seed is key.

 

Keeping the depth uniform can be done with the proper down pressure of the planter unit. There are many different styles of closing/firming wheels on the market. You may need to experiment on what works best for your operation and soils.

 

Quinn: Once poor and uneven corn emergence has occurred, there are limited options for correcting the problem outside of replanting. Therefore, prevention is critical. Delayed plants often struggle to compete with earlier-emerging plants and may ultimately reduce overall field yield potential.

 

To minimize emergence issues, evaluate your planter setup and field conditions to influence consistent seed placement and seed-to-soil contact. Planter components such as row cleaners, downforce systems, gauge wheels, seed firmers and closing wheels should be properly adjusted to achieve uniform seed depth, consistent placement into moisture and complete furrow closure.

Planting into suitable soil conditions is equally important. Avoid soils that are too wet to reduce sidewall compaction and poor furrow closure. Targeting increasing soil temperatures and consistent soil moisture at seed depth can promote more rapid and uniform germination and emergence.

 

Ritter: Those late emergers certainly reduce resources from neighboring plants without contributing to an abundance of yield. So, by that definition, one could consider them weeds.

 

There are ways to help reduce uneven emergence. Controllable factors include soil preparation, planter maintenance and seed quality. Specifically, cloddy soil conditions will interfere with good seed-to-soil contact or hinder emergence. Lack of uniform soil moisture also impacts emergence, as does poor planter maintenance. Check such items as the disk openers and press wheels. Your planter is the most important piece of equipment you have. It is the first step to a successful harvest.

 

When it comes to seed, early vigor and emergence scores are important. Plant those hybrids early that have the best early vigor and emergence scores to assist you in getting more uniform stands.