The drought monitor report as of Tuesday, Nov. 15, indicates the same drought conditions as last week and the snowfall wasn’t enough to change things. We are still in extreme drought and exceptional drought is creeping towards our area again. It’s pretty grim. The six to ten-day outlook (Nov. 22 to 26) indicates a 40 to 50% chance of above normal temperatures and a 33 to 40% chance of below normal precipitation. The cold temperatures will slow that down a bit. The eight to 14-day outlook (Nov. 24 to 30) indicates a 50 to 70% chance of above normal temperatures and a 33 to 40% chance of above below normal precipitation. Below normal precipitation heading into the driest time of year isn’t promising.
While cold temperatures this time of year aren’t uncommon, the past week of nighttime temperatures in the middle to lower teens for an extended period of days is unusual. Some producers are a bit concerned about their wheat crop. Should they be? And if so, why?
If this were a “normal” year with some soil moisture allowing for normal establishment of the crown and roots with wheat planted and germinating as we would want, the answer would be very little concern. Maybe some leaf burn. But this is far from a normal year. The area is mostly in extreme and exceptional drought and has been for an extended period. Even though many fields of wheat have emerged, emergence took longer than usual with dry soils. The potential problem is twofold: the plant and the soil.
The development of the plant has a great deal to do with its ability to withstand cold temperatures. Remember, the growing point is in the soil now at planting depth. A well-developed crown with decent growth helps insulate the growing point. Next, a well-developed root system helps, one with secondary root development. A poorly developed root system is more susceptible to damage. And a plant cells with adequate moisture, especially the roots and growing point, are also better able to withstand cold. The final concern is transitioning from warm to cold temperatures. Wheat gains winter hardiness based on two environmental factors: daylength and temperature. Decreasing daylength causes physiological changes for overwintering. Decreasing temperatures also trigger these changes. If cold occurs gradually, the plant changes cell contents and is normally good. Abrupt changes are more challenging for the plant and it’s more likely to evidence damage to above ground vegetation. Not as likely to damage the growing point.
Soil moisture is the other big factor. We just discussed the impact of soil moisture, or lack of it, on germination and growth. The other concern is soil temperature. Moist soils have a higher specific heat and cool much more soil and have less variation during a 24-hour period than dry soil. There is a much greater chance of soil temperatures at the depth of the growing point damaging it with extremely dry soils.
Having said all this, it’s still unlikely there was significant damage to the crop and the growing point should be fine. However, if soil moisture remains very short, there is a much greater chance of damage to the growing point as winter progresses.
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.
