When it comes to wheat stands, how thin is too thin? In some areas of Kansas, the wheat crop came up late or stands have been unusually sparse this year, according to Jim Shroyer, K-State Research and Extension crop production specialist.
Where this is the case, producers may want to know if these fields should be kept or destroyed and planted to a summer row crop, Shroyer said.
Crop insurance considerations play an important role in this decision, but there are also agronomic and economic factors to consider, said Shroyer, who is the Extension state agronomy leader.
"Wheat yields are normally only 40-60% of normal when it is seeded or emerges very late. But even if the field has only half a stand, it is probably worth keeping this year," he said. "With the high price of wheat currently, a field with only 15- to 20-bushel yield potential may be worth keeping this year; whereas in previous years that may not have been justified."
One thing to keep in mind is that late-emerged wheat will mature later than normal, and may face more disease pressure, he said. Spring weather conditions are especially critical to the ultimate yield of late-emerged wheat.
"It is too early at this point in the season to make a reasonable estimate of yield potential. The earliest producers can start estimating yields is when the wheat reaches the jointing stage. There are still many factors that can influence yields after that time, but counting the number of tillers present at jointing time can at least provide a rough estimate of yield potential," he said.
To make this estimate, producers can assume that each tiller per square foot will equal about one bushel of grain yield, Shroyer said. For example, if there are 20 tillers per square foot at jointing, producers could estimate the yield potential to be about 20 bushels per acre.
"This is far from precise, but it will suffice as an early ballpark estimate. Normally, only about 70-80% of the tillers present at jointing will make it to heading, but this is highly dependent on weather conditions and initial tiller density," said Shroyer.