Agronomic Update – April 14, 2020

 

Needless to say, we are living in some interesting and challenging times, as we live out Quarantine Day #!?!?….a little humor to get started…..

I’m sure we can all relate to this comic strip….especially those who have children in the house ALL DAY…..

We hope and pray that everyone is doing well, staying healthy and safe, and prepared for the planting season!

Topics for this Update:

  • Temperature, Soil Temperature and GDU accumulation.
  • Cold soils and Corn Emergence
  • Things to Keep in Mind when Planting Early
  • Hybrid Stress Emergence Ratings

TEMPERATURE

The below two maps show the temperature probabilities for the 6-10 day and 8-14 day forecasts:

The next two maps show the 8-14 day precipitation probability forecast and the weekly average 4-inch bare soil temperature on 4/13/20

As we can see, the forecast for the next 7-14 days is for a warming trend with slightly above normal precipitation in this period.  This bodes well for getting some corn/soybeans planted in April.  It will be interesting to see what the precip forecast does over the next couple of weeks.

Notice as well the soil temperature map.   We see that the weekly average on 4/13 was 49 degrees….keep in mind this is bare soil.  This means that soil temperatures were warming up quite nicely before this current cold spell.  I would expect however, to see this weekly average fall to the upper 30’s or lower 40’s by Saturday am.   Also, GDU accumulation from March 1 to April 13 for this year is 131 GDU’s.  While the specific number doesn’t mean much right now, it does show that we have had some heat over the past six weeks….during this same time frame in 2019 we had zero GDU’s accumulated.  All of this means that soil temperatures will rebound quickly once we experience a period of warmer temperatures.  We are in better shape than a year ago at this time heading into planting.

COLD SOILS AND CORN EMERGENCE

Optimal soil temperatures for planting corn is 50 degrees and above.   Keep this in mind as we head into next week and then see what the average soil temperature has done over the past seven days.   Imbibition of cold water can lower germination rates and cold soil temperatures can delay emergence allowing for more diseases to set into the seedling.  Watch the forecast if it looks like we will get into the 60’s and 70’s our soil will warm up relatively fast.  Here is a quick look at how a seed germinates.  Imbibition of soil water happens within the first 48 hours and is why it is critical to plant when soil conditions and soil temperatures are right.  Main to keep in mind is that best time to plant is into a 2-4 day warm temperature period after planting.  Most reduced stands occur when planting into a cold spell or before giving the soil temperatures time to warm up some right after a cold period.

See link for further information:  Corn Soil Temp and Emergence

THINGS TO KEEP IN MIND WHEN PLANTING EARLY

  • Fluctuating soil temperatures can cause imbibitional seed chilling, erratic emergence and cold temperature injury
  • Average last freeze date:  3rd-4th week in April for Central Nebraska
  • Soil may be too wet which can lead to side wall compaction, crusting and poor seed to soil contact
  • Herbicide injury can occur more often in cool, wet soils where the plant isn’t growing at an optimal pace
  • Soil temperature fluctuates more in the top 1” = one reason why we plant at 2”
  • Seed to Soil contact is key to fast emergence and stand establishment

PLANT FIRST RECOMMENDATIONS

One of the most frequently asked question is “What product should I plant first?”  With the cooler soil temperatures at the beginning of planting we believe that it is important to start with a hybrid that shows strong emergence and early vigor.  The below bullet points show our recommendations for “plant first” products if soil temps are cool. The hybrids are listed by maturity not by how well they emerge.  These are products that have shown to have strong emergence and early vigor over the past several seasons.  Selecting one of these hybrids to start with can help provide the best chance for optimum emergence when soil temperatures are cooler at the start of planting.   However, considering how fast our soil temperatures should warm up this spring, and if one is planting into a warm stretch, we don’t have an issue with starting with most any hybrid.  Keep in mind the 2-5 day forecast ahead of anytime you are planting.  Remember also, that we will continue to experience soil temperature fluctuation as we go through planting.

  • 105-109 CRM – P0421, P0589, P0622, P0950
  • 110-118 CRM – P1082, P1089, P1108, P1138, P1244, P1379, P1563, P1828

Please contact us with any questions or comments you may have.  Thank you!!

 

 

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