Corn planting progress and planting considerations

BY JASON KELLEY, WHEAT & FEED GRAINS EXTENSION AGRONOMIST, ON APRIL 2ND, 2013

As I write this article, it is raining and 39 degrees, which seems about right on par for this corn planting season so far.  Hopefully next week will bring warmer and drier conditions.    Planting overall has been slowed/delayed or non-existent, depending on where you are at in the state throughout the month of March because of cool and wet conditions.   According the National Agricultural Statistics Service Report on April 1, we have planted 22% of the Arkansas corn crop and only 3% has emerged.  Last year at this date we had planted 56% of the acreage, compared to 32% for the 5-year average.   Air and soil temperatures overall remain below average.  During the week ending March 31^st, state average air temperatures were 5-10 degrees below the 30-year average.

The March planting intentions report last week estimated that Arkansas would plant 1 million acres of corn in 2013, the largest corn acreage since 1951.  So we have a ways to go before corn planting is wrapped up!!

Cool temperatures and rainfall has really slowed corn emergence this year.  Many fields in South Arkansas that were planted 3 weeks ago are just now beginning to spike.  The photos below show the slow development in plots that I have this year.  This corn was planted March 14^th at Marianna and hopefully will be close to spiking later this week after being planted for 3 weeks.

Planted March 14 Photo Taken March 21

Planted March 14. Photo Taken March 28

Many Producers Are Asking If They Will Get A Stand

In the digging that I have done in the past few days evaluating condition of corn seedlings, the seed that I have seen appears to still be healthy and is still slowly emerging and should emerge with a little more time.   However some fields are likely not to be as uniform emerging as we would like to see.  In looking at corn today, some seedlings were spiking and others still had not emerged, but should be emerging in the coming days.  Under ideal conditions, we would like for all seedlings to emerge on the same day so that all plants are uniform.  But as slow as emergence is now, a couple days difference in emergence may not make as much difference in yield as is perceived.

I have gotten a couple reports of seedlings that had rotted, but I have not seen this first hand yet.  All of the corn that I have looked at appeared healthy at this point.  Fields that have had water standing at the bottom of the field or fields that have poor drainage are more likely to have reduced stands.

What Plant Population is Considered Adequate?

Typically for irrigated fields we are aiming for a plant population of 32-34K/acre.   Some stands of early planted corn this year may not be “optimum” after the stress that they have been through.  Replant decisions depend on a lot of variables including the replant policy for the hybrid in question, what date you can get in the field to replant, what kind of stand you have, and how uniform the stand is?  In plant population studies on irrigated corn in past years, plant populations of less than 26K are generally low enough that replanting may be needed provided you are in the planting window where adequate yields can achieved.   A 75% replant policy (typical, but varies by company and hybrid) by seed companies makes replanting decisions a little easier provided seed is available to replant.  Plant populations of 28K/acre or more and are somewhat uniform should be adequate to maximize yields for most hybrids.   IF REPLANTING, ALWAYS DESTROY THE FIRST STAND PRIOR TO ANY REPLANTING OPERATIONS. 

How Late Can We Plant and Maintain Yield?

A lot of calls are coming in about whether it is too late to plant corn.  My answer – we are just now getting into the “optimum” planting window for most of Arkansas.  After the 2007 Easter freeze much of our corn was replanted after April 15^th and resulted in record yields.  In reviewing 5-years of planting date studies that were conducted from 2008-2012 at Rohwer, Marianna, and Keiser evaluating only Bt hybrids, estimated relative yield potentials are listed below:

Estimated   Relative Yield Potential Based on 2008-2012 Planting Date Trials in Arkansas   (Bt hybrids only).
	Keiser	Marianna	Rohwer
Planting   Date	————–% Relative Yield   ————–
April 1-20	100%	100%	100%
April 20-30	100%	100%	95%
May1-10	98%	95%	90%

The take home message is that we still have plenty of time to get corn planted without sacrificing yield.

Some might disagree, but I feel that how the crop is managed throughout the season is far more important than actual planting date within a normal planting date (March 15-April 30) for Bt hybrids.   There has also been talk about needing to grow fuller season hybrids when we plant later.  Based on results from our planting date studies there is no need to change hybrid maturity when dealing with 110-120 day hybrids, which is what we are typically planting.  If you have a good hybrid ready to plant, don’t change based on perception that you need a fuller season hybrid.

source :
http://www.arkansas-crops.com
planting progress and planting considerations