Q and A: Why is Corn Emergence Uneven This Year?

Jun 01, 2020

By Jenny Rees

Question:

Why is corn emergence uneven this year?

Background:

Planting conditions seemed to be “perfect” regarding soil moisture and a warming trend of soil temperatures this year in late April through early May. This allowed a large percent of corn and soybean acres in Nebraska to be planted earlier than in previous years. Because conditions seemed so good, the question is why emergence has been uneven in some fields this year.

Answer:

Seed depth and the environmental variability surrounding the seed may explain the most in regards to variation in soil moisture, temperature, and residue cover. Every field situation is unique. The following is what we have seen and heard this year.

Where tillage, clean strips, and residue cleaners were used, we’ve observed situations where the corn emerged a few days earlier where residue did not blow back over the seed row compared to where it did. Those two situations provide differences in soil moisture and temperature.

A few farmers who “planted green” into rye cover had some interesting observations. They had more uneven corn emergence where the rye was killed prior to planting compared to where they planted green. They said the rye that was alive when planting held the residue in place compared to the rye that was killed prior.

There were a few days in late April where we seemed to quickly lose surface soil moisture. Some fields may have had better moisture at seeding depth, but variation in seeding depth within the row impacted the moisture around the seed for germination and even emergence.

No-till fields and fields planted into cover crops have stayed cooler since early May which has delayed growth and emergence.

Strip-till may have allowed for soft seed bed conditions for uneven depth and some moisture loss. Another thing observed prior to this past week’s rains was fertilizer burn on roots in some fall and spring strip-till situations. The greatest moisture loss has occurred in conventional till fields and those which were more cloddy tended to have the most uneven emergence.

There have been isolated cases of insect issues such as wireworm and seed corn maggot.

There could be some potential seed lot/cold germ issues. One thing to consider is there are near isolines of traited/non-traited seed in the Refuge in Bag (RIB). So, there could potentially be some differences in emergence under stress/cold germ there.

The following article on Growing Degree Units and Emergence may also be helpful information.

Yield Impacts:

We realize the uneven emergence has been bothering farmers. Yield loss may not be as great as one thinks. Research from Purdue University found yield reductions of 6-9% for plants emerging 1.5 weeks later than a uniformly emerging stand. They also found yields of uneven stands to be similar to planting the stand 1.5 weeks later.

Source : unl.edu

Video: Moving Ag Research Forward Through Collaboration

BY: Ashley Robinson

It may seem that public and private researchers have different goals when it comes to agricultural research. However, their different strategies can work in tandem to drive agricultural research forward. Public research may focus more on high-risk and applied research with federal or outside funding, while private sector researchers focus more on research application.

“For me, the sweet spot for public private sector research is when we identify problems and collaborate and can use that diverse perspective to address the different aspects of the challenge. Public sector researchers can work on basic science high risk solutions as tools and technologies are developed. They then can work with their private sector partners who prototype solutions,” Mitch Tuinstra, professor of plant breeding and genetics in Purdue University’s Department of Agronomy, said during the Jan. 10 episode of Seed Speaks.

Public researchers they have the flexibility to be more curiosity driven in their work and do discovery research. This is complimentary to private research, which focuses on delivering a product, explained Jed Christianson, canola product design lead for Bayer CropScience, explained during the episode.

“As a seed developer, we worry about things like new crop diseases emerging. Having strong public sector research where people can look into how a disease lifecycle cycle works, how widespread is it and what damage it causes really helps inform our product development strategies,” he added.

It’s not always easy though to develop these partnerships. For Christianson, it’s simple to call up a colleague at Bayer and start working on a research project. Working with someone outside of his company requires approvals from more people and potential contracts.

“Partnerships take time, and you always need to be careful when you're establishing those contracts. For discoveries made within the agreement, there need to be clear mechanisms for sharing credits and guidelines for anything brought into the research to be used in ways that both parties are comfortable with,” Christianson said.

Kamil Witek, group leader of 2Blades, a non-profit that works with public and private ag researchers, pointed out there can be limitations and challenges to these partnerships. While private researchers are driven by being able to make profits and stay ahead of competitors, public researchers may be focused on information sharing and making it accessible to all.

“The way we deal with this, we work in this unique dual market model. Where on one hand we work with business collaborators, with companies to deliver value to perform projects for them. And at the same time, we return the rights to our discoveries to the IP to use for the public good in developing countries,” Witek said during the episode.

At the end of the day, the focus for all researchers is to drive agricultural research forward through combining the knowledge, skills and specializations of the whole innovation chain, Witek added.

“If there's a win in it for me, and there's a win in it for my private sector colleagues in my case, because I'm on the public side, it’s very likely to succeed, because there's something in it for all of us and everyone's motivated to move forward,” Tuinstra said.