QUICK AGRONOMIC UPDATE – August 3, 2022….finishing strong…

TEMPERATURES & GDU ACCUMULATION:

As of August 3rd, we have accumulated approximately the following for Growing Degree Units in 2022:

Planting Date GDD’s2022 Average GDD Departure from average

April 21 1957 1927 +30 (+ 1 day)

April 28 1891 1877 +14 (even)

May 9 1828 1783 +45 (+ 2 days)

We have not gained any extra days since the last update a week ago, which stands to reason, as it is hard to gain ground in July, as this is when we get our heat anyway. However, temperatures for the next 6-14 days are predicted to be above normal yet, so we may gain going forward. This may potentially be a negative though, as the crop may ‘push’ a little too fast….

We are now into the critical grain-fill period for both corn and soybeans. How we finish the last 30-45 days will play a big role in final yield. As such, I am including a link to an agronomy podcast that I feel is not only interesting, but has some pertinent topics for this time of year. I encourage you to give it a listen. The podcast is facilitated by two Pioneer Agronomists and the guest is Dr. Jeff Schussler. They talk about a myriad of topics from nutrient uptake and placement, strip-till, residue, late-season N, crop management after flowering, among others. Dr. Schussler was on the lead for Pioneer in developing AquaMax drought hybrids and spent most of his career with Pioneer on drought work and plant physiology and drought technology. Dr. Schussler spoke at our Pioneer Plot Tour some 10 years ago as well, so some of you may remember him. He has great knowledge on the corn plant itself and drought…

Kick’N Dirt Podcast – busting Myths w/ Dr. Jeff Schussler

Highlights on a few topics from the Podcast:

Crop management after Flowering and Extended Staygreen: For many years we have talked about staygreen. The longer one can maintain plant health through the grain-fill period, the greater impact on final yield. This comes about through harvesting sunlight (capturing carbon) which increases kernel size and test weight. The hybrids of today don’t respond in the same way they did in the past. There has been great change, with plant breeding and genetics, over the last 20-30 years.
Late-season N: There has been much discussion the last number on years on the corn crops need for N after flowering. In the podcast, Dr. Schussler talks about how, in today’s environment and hybrids, we have an extended staygreen that was not present 15-25 years ago. This extended staygreen is driving yields. In the ‘old days’, before fungicides, trait technologies, etc., once the plant reached R1-R2, the plant would start to degrade quickly and it would be a ‘race’ to harvest. N needs after flowering at that time were probably 20-30# in Dr. Schussler’s opinion. Now-with the extended staygreen-after flowering N needs in today’s hybrids are, in Dr. Schussler’s opinion, potentially more like 100-120#. With this extended staygreen an ongoing uptake of N is needed to support that. This leads to more N management throughout the growing season. The extra N is potentially helping the weaker plants in a field out than the stronger ones. This is potentially where products like Pivot Bio ProveN40 and Utrisha may shine, as they are producing N throughout the growing season.
Taller corn vs. shorter corn: In the podcast, they discuss taller corn vs. shorter corn in relation to final yield. It all comes down to plant biomass, specifically, leaf biomass. If a shorter plant has the same leaf biomass as a taller plant than most likely there should be little difference. However, it is an axiom in corn production that ‘what you see above ground, is what you have below ground’….less above means less below. In other words, the root biomass (total root volume in a soil) is potentially less in a shorter plant than a taller plant….the total volume of soil contacted by the root system is less potentially, even though rooting depth may beyond 40+”. Grain-fill period management then, becomes more critical to maintain high yields in this environment. The plants are not able to scavenge as efficiently for water, nutrients, etc., with a lower root biomass. This means that we need to make sure the water and nutrients are available within the root zone, especially in the ‘prime’ area of the top 18″.
AquaMax hybrids and breeding: Nice discussion on the AquaMax drought hybrids…plant physiology and genetics…heat stress vs. drought stress….leaf rolling….
Heat stress, High daytime temperatures, plant respiration: Interesting discussion on plant respiration and high daytime and night time temps, canopy temperature….
Last 10-15% of yield is Kernel Size: 85-90% of yield comes from ears per acre x kernels per ear. 15% of yield is kernel weight. Important for high yields to maintain uniform kernel size throughout the ear. Run out of nutrients or water late and kernel size is reduced, which is reduced test weight.

Quick Crop Observations:

ET rates continue to be high. The past 7 days saw total ET for corn of 2.30″…compared to 1.20″ last week in the cooler temperatures. The last 7 days had a .08″ daily ET rate above average…..0.33/day vs. average of 0.25″. With the predicted high temperatures, expect ET rates to continue to be higher than average for both corn and soybeans over the next 7-10 days.
We are seeing more NCLB lesions in the area. Not heavy, but the disease is present. Still highly recommended to apply a fungicide if you have not already done so. This needs to go on ASAP if you do.
The hot, dry conditions are conducive for spider mite development in corn. Please keep this mind as you are scouting your fields for any potential outbreak.

Thank you for your support! Please let us know any questions or concerns you may have.

Starman Seed Service, Inc.