What has been learned after Four Years of Studying Temperature inversions.

Missouri Temperature Inversion

Integrated Pest Management of Missouri University has been monitoring inversions since beginning of 2015. This has been through a monitoring network established throughout the state. They have also studied how inversions affect auxin chemicals, particularly dicamba. With Xtend already in the market place for several years and Enlist on the horizon, there continues to be a concern on how successful apps on our phones predict inversions, whether inversions occur only at sundown, & the fact that not every field is created equal when it comes to the temperature inversion. Below is the link to read their article. I have included the bullet points from the paper for those who want to just skim the highlights. If you have time, though; it is a thorough piece based on real world studies.

Network of inversion monitoring stations that are tracking inversions at heights relevant to ground pesticide applications. Counties in blue indicate the 3 original inversion monitoring stations which were equipped in 2015. Counties in red indicate newer inversion monitoring stations that went online in 2017 and 2018.

1. Inversions are common. In June & July, 2018: Inversions formed more than 60% of the evenings.

2. Inversions begin forming prior to sunset. Sometimes more than 2 hours.

3. A field's surroundings influence the time when inversions form. Inversion form more quickly downwind of tree lines, for example.

4. Cool air is going to the lowest point of a field. Low areas are at greater risk for dicamba injury.

5. Mobile apps are still in validation stages. Most apps base data on higher heights than at ground level where the inversion forms

6. Dicamba can be detected in the air more readily following application during inverted air temperatures. IPM detected 3x more dicamba in the air applied in an inversion versus on label app during the day.

7. Smoke bombs are good indicators of inversion forming. MU used Enola Gaye Smoke Grenades to see how quickly the smoke cloud dissipates.

-In conclusion, much has been learned about inversions and much more is to be learned on this topic. On the ground "cues" like clear skies, reduced winds, & sound/smell amplification can be signs of an inversion to be formed or forming.

Here is the link to the article: https://ipm.missouri.edu/IPCM/2019/4/inversion/

All credits go to: AUTHOR

Mandy D. Bish University of Missouri Division of Plant Sciences (573) 882-9878 bishm@missouri.edu

Kevin Bradley University of Missouri Division of Plant Sciences (573) 882-4039 bradleyke@missouri.edu

March 25, 2019 Corn/Soy Update

“Things which matter most must never be at the mercy of things which matter least.” 

― Johann Wolfgang von Goethe

Temperature from April 16, 2018

Here are some thoughts to take with you this week for those that received little rain & can use this weather for field work.

• Weather outlook: End of week storm looks to bring substantial rain according to the ECMF guidance. However, there are model disagreements on the amounts to fall in SW MO and SE KS. It looks to be more rain towards Joplin and less towards Belton at this point. The warmth we will have over the next few days is storm induced but may bring field work opportunity. Soil Temperatures this morning at 7am were 48.9 at 2” and 48.4 at 1.5” up from Saturday morning of 46.7 at 2”.  By the weekend however; we may see night air temps in the mid 30s, bringing soil temps back down.

Keep this in mind with field work this week, some of it is repeat from the last report. Just updated for the weather conditions ahead:

1. If P & K is not on, prioritize this app this week.  The quicker we can spread this on the sooner it can start breaking down, especially on soils that are at critical levels.

2. Apply NH3 if soil conditions are dry enough. Let’s stress the part about dry enough. Smearing in this product can cause not only losses, but also severe compaction outside of tram lines. Wet soils are extremely vulnerable to being damaged. As soils approach capacity levels and because water cannot be compressed, the tire track creates a ram effect of pushing the compaction layer deep into the subsoil below our normal tillage but harmful in establishing deep roots for the crops. As has been mentioned in the previous article corn response to early N is less important than the damage that can be caused by applying it with high compaction and N losses. But, if soil conditions warrant; apply.

3. Evaluate weeds, and apply burndown as needed. Killing winter annuals before they get any bigger is important to allow sunlight to warm and dry saturated soils, inhibit host sites for egg laying black cutworm moths, & maintaining control of marestail before they shoot the stalk and become resistant to herbicides. (Keep an eye on your corn stalks going to soybeans as well.) If you are using tillage, keep soil compaction in mind. Like was just mentioned, pushing a tillage operation on too wet of soils will degrade soil structure and cause problems with water infiltration later on. There are cheap generic chemistries that can be used to kill and hold back the weeds till we plant if needed.

4. And, Beck’s PFR data shows that best soil conditions make more of a consistent yield difference than planting exactly on time with corn. (Soybeans are more calendar driven due to their sensitivity to daylight.) This means soil temperatures averaging at least 50 degrees or more and consistent adequate moisture not too wet and not too dry in the seed zone. Planting at 2” helps even out the high/low temperature swings from day to night, and also places the seed in a uniform moisture zone. In dry conditions, the seed may need to be planted up to 3” to find consistent soil moisture. While this may seem extremely deep, understand that the coleoptile on the seed shoot of corn has the potential to stretch to a whopping 6”. With the cold temperatures ahead, be cautious of planting. The weather 3-5 days after corn is planted makes as much or more impact as the day it is planted. Be watching the 5-7 day forecast and adjust accordingly. Also, go over that planter one more time! Making sure the equipment is giving us the consistency that is needed for even emergence. Proper seed to soil contact is vital to this. Those few bushels lost from improperly installed  or set equipment is all in your profit zone!

5. Finally, Please be safe! Avoid backing up equipment, go around the block if needed. Be aware of your surroundings and who is in your area. The only thing we can’t replace is our loved ones. Have a good week!

If you need anything, feel free to call any time.