The drought monitor report as of Jan. 30 shows the continued improvement thanks to the weather of the last week. A third of the state is now totally out of drought conditions and another 30% is only moderately dry. The six to ten-day outlook (Feb. 6 to 10) indicates a 70 to 80% chance of above normal temperatures and a 40 to 50% chance of above normal precipitation. The eight to 14-day outlook (Feb. 8 to 14) indicates a 50 to 60% chance of above normal for temperatures and a 40 to 50% chance of leaning to above normal precipitation.
Today, in the doldrums of February and heading into March, let’s briefly discuss what causes all plants, but especially our crop plants to flower. It’s more complicated than you might imagine.
• First up is winter wheat. Two things have to happen for winter wheat to flower and produce grain. Since it is planted in the fall and has to get past winter and freezing conditions to flower and produce seed it possesses a safety mechanism to insure no matter how well it grows in the fall, it won’t flower until spring. It much be vernalized, accumulate a so much cold before it will go ahead and flower. The amount of cold it needs varies by variety. Some varieties, usually full season, need a great deal while others, short season varieties, need relatively little but it matters. If you plant winter wheat, say in March, it will germinate, establish tillers and grow but never flower. The second thing it needs is increasing day length (decreasing night length). Many cool season plants like winter wheat are termed short night plants. These two factors help the plant get past winter. And increasing temperatures and heat accumulation in the spring also play a role.
• For our summer crops (corn, grain sorghum, soybeans) they have a different challenge. They need to flower and produce viable seed before cold temperatures arrive in the fall. All respond to temperature but the grass crops here are different than soybeans.
• Corn and sorghum, especially corn, reach the growth stages of the plant through heat accumulation. If you know how much heat accumulation has occurred, term Growing Degree Units (GDD), you know at what stage of growth the plant is at. It takes so much heat for flowering and for grain maturity. This makes sense based on where the plants originated from. As in wheat, the amount of heat necessary varies by hybrid. There are two exceptions. Very short season corn, which isn’t grown here is sensitive to increasing night length (decreasing day length) and sorghum can essentially go into neutral for a period of time with unfavorable conditions.
• Finally, soybeans rely more on increasing, uninterrupted night length. They are short day/long night plants we plant here. Depending on the maturity group, the amount of night length varies. This amount keys the plant to initiate flowering. A given soybean variety planted say in mid-may and then Mid-June will start flowering at approximately the same time. For the corn and sorghum we plant, it’s heat accumulation that matters most.
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.
