By Scout Nelson
Understanding physiological maturity (PM) in wheat, barley, and oat is important for proper pre-harvest planning. This stage signals that the crop has reached its maximum kernel dry weight. After this point, the plant stops adding dry matter to the grain.
PM is the ideal time to swath the crop or apply glyphosate for pre-harvest treatment. However, while swathing can occur just before PM without affecting grain quality or yield, this is not recommended when using glyphosate.
At physiological maturity, kernel moisture is still relatively high, usually ranging from 20 to 40 percent. Properly identifying PM can help ensure that harvest preparations protect both yield and grain quality.
There are two main visual signs that indicate physiological maturity in small grains:
- Loss of green in the kernel -One sign is the fading of green color in the kernel, along with the appearance of a dark line or pigment along the crease. In a single spike, kernels do not mature all at once. The middle portion of the head often matures first.
- Loss of green in the peduncle -Another clear sign is the fading of green from the uppermost internode or peduncle, located just below the head. When this area turns a light green or yellow, it means that water and nutrient flow has stopped, and grain fill is complete.
By using these signs, growers can better time harvest activities, maintain high grain quality, and support overall crop success. Recognizing physiological maturity is key to smart harvest management in wheat, barley, and oat crops.
Photo Credit: istock-rustic
Categories: Minnesota, Crops, Wheat