Spring green up. What does that mean?
Green-up is not a growth stage per se, but it is a descriptive reference to how the field looks a darker green color as the weather warms up in the spring and plants come out of dormancy and the new growth covers the winterkilled tissue. In PA, this usually happens between mid-March (southeast PA) and late April (northern tier). However, with the warm winter we are experiencing this year, many fields in southeast PA are already greening up. Plant growth stage at green-up will depend on several factors like planting date and fall weather conditions. For example, two neighboring fields, one late planted and the other early planted may green up at the same time – the late planted can be at Feekes stage 3 while the early planted can be at Feekes stage 5. It is important to scout the field for accurate growth staging.
Why is green up important?
As the plants are coming out of dormancy, this is a time of fast growth that requires scouting and timely management.
What to scout for
Growth stage
This guide from the University of Wisconsin is an excellent resource for staging fields. Pay attention to fields at the Feekes stage 5 (the developing head is located just above the crown and is less than 1/8" long). This is the last stage in which some herbicides can be used without causing leaf injury. Further, after this stage the developing head moves above the soil surface and yield potential is decreased by wheel traffic damage.
Stand counts
See this video explaining how to perform a stand count. Yield potential of winter wheat is decreased when the number of (alive) plants falls below 20-25 plants per square foot. These numbers are based on an average of 3 heads per plant. Therefore, it is also important to look at the condition of the tillers. For example, if there are 20-25 (alive) plants per square foot but plants have less than 3 healthy-looking (usually with 3 or more leaves) tillers, yield potential will likely be decreased.
Winter survival
Winter survival can be assessed visually by estimating the percentage of dead foliage for a field or field management zone. If the percentage is high, and especially if this is coupled with a low stand count estimate, a simple winter survival test can be performed by digging up plants and looking for root regrowth at room temperature (bag test). See how to do a bag test at the end of this article.
Click here to read more psu.edu
Photo Credit: istock-ligora
Categories: Pennsylvania, Crops, Wheat