8/16 Corn Update

Corn Update:


We saw a lot of dents today.  Only a few places had “hard dents” or true R5.  Many of the hybrids are a soft dent and not quite to R5 yet.  It will surprise how things can move very quickly with the heat coming later this week.  You may not even see the milk line until it is at ¾, and looking at past notes, a hybrid may appear to be “soft dent” yet and be past ¾ milk line.


As we move into the final stages of grain fill, we have a lot of yield potential remaining in some hybrids, while others will not adjust as much.  As we know, hybrids that adjust kernel depth can have big swings in their yield results depending on how the final 30 days go.  A few hybrids we have experience with such as P0589, P0421, P0157, and P0075 genetics can adjust depth and their yields adjust as allowed.  A hybrid like P0306 tends to adjust ear length, which is why we see some aborted kernels on these ears already, but will typically have the same kernel size each year.  This is why sometimes we see a hybrid do very well in some environments and not as good in others.  A hybrid which will flex a lot gives us more upside potential but also downside potential.


With dents coming on, silage season will be here before we know it!  Here is some good info regarding corn silage from ISU Extension:



Harvest Tips (compiled from articles by the University of Wisconsin and University of Minnesota)

  • Optimum silage moisture harvest ranges for different structures are: 50-60% for upright oxygen-limiting silos, 60-65% for upright stave silos, 60-70% for bags, and 65-70% for bunkers. Silage too wet may not ferment properly and can lose nutrients through seepage. Silage is too dry when harvested has lower digestibility because of harder kernels and more lignified stover. It also does not pack as well.
  • Due to variability among hybrids and growing conditions, use of a commercial forage moisture tester or microwave oven is highly recommended. The kernel milk line can still be used as a guideline when to start sampling plants from the field for more accurate moisture testing. A chipper-shredder and commercial forage moisture tester work well for this. Begin moisture testing when the milk line is 20% of the way down the kernel for horizontal silos, and 40% of the way down the kernel for vertical stave silos. An approximate dry-down rate per day is about 0.5-0.6% per day.
  • For unprocessed corn, recommended chop length is 0.375” theoretical length of cut.
  • For processed corn, recommended settings are a 0.75” theoretical length of cut with 0.08 to 0.12” roll clearance. The increased cut length reduces horsepower requirements while maintaining optimum particle size. Breakage of cobs and kernels increases surface area which improves digestibility, reduces cob sorting, and results in higher density silage that packs better. A crop processors greatest benefit may be when there are harder kernels resulting from delayed harvest or drought. While crop processors are not cheap, they generally provide a higher-quality silage product that can increase milk production by about 300 pounds per cow per year.
  • Recommended cutting height is generally 4 to 6”, as it maximizes silage yield and milk per acre. Cutting height can be used to adjust moisture content. Cutting at 12 inches decreases forage moisture 3-4%, decreases yield 10-15%, but increases forage quality 8-12%. So overall Milk per acre is only reduced by about 3-4%. This type of management could be significant when working with a custom chopper on their schedule.
  • There is potential for high nitrates in drought-stressed silage, especially if harvested within 10 days of rainfall (since rainfall increases crop uptake of soil N). If there is any doubt about nitrate content, test the feed. Silage with high nitrate levels can be managed by dilution with other feeds and also by increasing the cutting height to 12”.
  • When harvest begins, fill silos rapidly to reduce exposure of silage to oxygen and to reduce fungal growth. For bunker silos, pack silage as tightly as possible in progressive wedges in depths of 6” or less.


If you have questions about your silage moisture – we have a cooker, we would be glad to cook a sample for you and let you know what the % moisture is at.


Rootworms – the numbers are still variable.  Treatment of insecticide with fungicide last week took many of the populations down.  We are still finding high numbers and a dry soil in the fall will create the same problem as last year.  They will be able to lay eggs deeper in the soil, creating higher rates of survival even in a cold winter. If you plan on raising corn on corn in 2021, you will need to make additional management decisions to keep rootworm populations in check.


Trap Years Corn beetle bomb in past # beetles
Week #1 Aug 3rd Week #2 Aug 10th Week #3 Aug17th
1 20+ No 8 25
2 20+ No 7 3
3 30+ No 82 26
4 24 Some 2 0
5 24 some 2
6 5+ Yes 2 2
7 5+ no 14 13
8 15+ Yes 15 6
9 15+ no 48 9
10 2 no 7 6 Insecticide applied previously to putting out a trap
11 15+ no 47 172
12 10+ no 14 3
13 5+ yes 8 0
14 5+ no 6 15
15 10+ no 96 71
16 10+ no 109 40
17 10+ yes 0 1
18 5+ yes 2 0
19 5+ yes 0 1   Insecticide applied this week if bold & underlined
20 5 yes 0 1
21 10+ no 20 3
22 10+ yes 17 ?
23 0 no 7
24 10+ yes 22
25 ? yes 0