Corn
Growth & Development
Most of the corn that I have seen this week is in either the late R4 (Dough) or the R5 (Dent) growth stage. A few fields are approaching the final growth stage R6.
R6 – Physiological Maturity
- Occurs approximately 66‐70 days after silking.
- R6 is reached after the milk line disappears and the starch has reached the base of the kernel.
- Kernels have reached maximum dry weight.
- Kernel moisture is about 35% at physiological maturity.
- Black layer occurs after physiological maturity and serves as a visual verification that the plant is mature. Black layer typically occurs at 30% moisture but varies by hybrid and environment.
- Husks and many of the leaves are no longer green, but the stalk may be green.
- Only external stress can reduce yield now, such as plant lodging or insect feeding.
Scouting
At this growth stage look for:
- Ear rots.
- Stalk rots.
- Anthracnose top dieback.
- Stalk lodging.
- Abnormal ear fill which identifies periods of stress.
- Weed escapes (especially Palmer and Waterhemp).
This is also a good time to get an accurate yield estimate.
Soybeans
Growth & Development
Soybeans are continuing to mature. Last week I highlighted the R7 growth stage, the last growth stage is R8 full maturity.
R8 – Full Maturity
- 95% of pods reached mature color
- Mature pod color does not necessarily indicate that beans are ready to harvest
- 35% grain moisture in freshly matured pod
- 15% within another 5 to 10 days
- Below-optimum plant stands cause more branching, low pod heights & can delay maturity
- Above-optimum plant stands increase lodging.
Scouting
At this growth stage look for:
- Green stem syndrome.
- Lodging
- Sprouting seeds
- Pod shattering
- Weed escapes (especially Palmer and Waterhemp).
This is also a good time to check soybean yield potential.
County Rainfall Update
