The drought monitor report as of Tuesday, Sept. 3rd shows a very slight deterioration in drought conditions for the state. The rainfall received last week wasn’t enough to change our moderate drought conditions. The six to ten-day outlook (Sept. 10 to 14) indicates a 50 to 70% chance of likely above normal temperatures and a 50 to 60% chance of likely below normal precipitation. The eight to 14-day outlook (Sept. 12 to 18) indicates a 60 to 70% chance of above normal temperatures and a 40 to 50% chance of leaning below normal for precipitation. Definitely not what the upcoming wheat planting season needs. It will speed up the fall harvest.
Harvest season is rapidly approaching. Corn harvest is just starting and soybeans and milo aren’t far behind. Some rye for grazing has already emerged and wheat planting, especially for pasture is quickly approaching. So today, as we wait for things to pick up, let’s briefly discuss how plants respond to weather and climate.
A great deal of how plants react depends on where they originated from and in some cases how we have modified them genetically for adaption to a given region. Remember few of our crop plants actually come from our region and the Midwest.
• How do plants know when to bloom? For corn and the most part sorghum, it’s primarily heat accumulation. The plants growth stage is determined by how much heat it accumulates and flowering is keyed to that. The specific amount of heat necessary is keyed to the specific hybrid. For soybeans we plant, it’s increasing uninterrupted night length. When that amount of night length is reached, the plant initiates flowering. Soybeans are trying to produce seed before a frost. Winter wheat we plant has two cues.
Again, the exact amount depends on the variety. First, the seeding must be exposed to a certain amount of cold temperatures, termed vernalization. Without that it will never flower. If you plant winter wheat in March, it will germinate and grow but never head out. The second factor is increasing day length. Once a predetermined amount of day length is achieved, combined with vernalization, it will initiate flowering.
• How does winter wheat prepare for winter? A wheat plant undergoes two changes to help it survive winter. It grows prostrate leaves and changes cell chemistry as winter approaches to help it survive. However, these changes have to start before the actual below freezing temperatures. So, decreasing temperatures play a role but more importantly, it’s decreasing day length that cues it to prepare for winter.
• One last example for weeds and native plants. Small-seeded weed seeds won’t germinate unless they can sense light as they are too small to emerge if deep in the soil. And many summer weed seeds won’t germinate unless exposed to cold temperatures so they won’t germinate until after the worst of winter is passed.
Dr. Victor L. Martin is the agriculture instructor/coordinator for Barton Community College. He can be reached at 620-792-9207, ext. 207, or martinv@bartonccc.edu.
