After years of battling growing conditions that are too dry, western Kansas wheat producers are now seeing poor emergence in some fields because of last month's heavy rains.
Jeanne Falk-Jones, K-State extension agronomist based in Colby, said the hard rain events caused some fields to crust, making it hard for the wheat plant's fragile coleoptile to break through the soil surface.
She says other fields had rain wash soil into freshly planted furrows and bury the seed much deeper than the producer intended, making those plants slower to emerge.
Producers may need to evaluate the stand
"Even though we have topsoil moisture this fall, we are still seeing some establishment problems," Falk-Jones said. "It's certainly not something we see in every field, but there are a number of producers in the Colby area scouting fields and trying to make decisions about replanting. More often than not, if the wheat was already up when the rains came, it's probably OK, but if that seed is trying to break through a crust or is too deep, producers may need to evaluate the stand."
In a recent update from K-State's Agronomy Department, Extension Agronomist Jim Shroyer noted that if a producer is finding young plants that have not emerged and have a coleoptile that is crinkled, it is a sure sign the plants could not break through the crusted topsoil. In the event that seed has been placed too deep - either by planting or by sifting soil - producers will find plants with scrunched coleoptiles and the plant's first leaf under the soil surface.~~~PAGE_BREAK_HERE~~~
Both scenarios cast a dim outlook for the stand. Producers with this problem will have to take extra measures to ensure healthy stand development, according to Shroyer.
"If the plant is trying to leaf out under the soil surface, it's very unlikely to make a stand and replanting may be necessary," Shroyer said. "Although crusting can happen across a variety of field conditions, we most often see seed being too deep in a scenario where a producer used a hoe drill and the rains washed extra soil into the furrows."
Factors to consider when replanting or interseeding
Important factors for producers to consider when replanting or interseeding are time of year, moisture supplies, variety tillering potential and yield goals. Producers are also encouraged to determine current plant population to help decide steps going forward. Citing a multi-year study at K-State's Belleville experiment fields, Shroyer recommends interseeding when an existing stand is below an equivalent of 30 pounds of seed per acre, or less than half of an expected stand.
The Sunflower Extension District's website hosts several informational guides that Falk-Jones recommends for producers evaluating stands. Included are a seeds per acre chart, optimum plant stand chart and a re-drilling decision guide.
In the event a producer decides to leave a thin stand, Falk-Jones recommends extra vigilance on the producer's part to ensure a successful crop.
"In a thin stand, the canopy will be open longer during the growing season and there will be increased opportunity for weeds to establish in the crop. Producers may want to have a more aggressive herbicide plan to keep weeds from becoming a problem," Falk-Jones said.
The full K-State Agronomy E-Update is available here.