Looking at weather effects on crops
By D. Bruce Bosley
CSU Extension Agent, Cropping Systems
In the South Platte basin, low temperatures have affected winter wheat and alfalfa in this region but in general less than one might expect. Freezing temperatures starting on April 9 and then through the last two weeks have frozen off the top growth of these two crops but for most locations they haven’t damaged the plant tissues in the soil or near the soil surface. Locations having snow cover during these storms should fare better than those where there was no snow insulating the plant crowns.
For alfalfa the freeze damage on above ground stems and leaves is akin to taking a first cutting. Upon warm-up alfalfa plants will resume their growth using stored energy from roots and crown tissues. Freeze damage and slow growth through April will likely delay first cutting.
Most winter wheat plants north of I-70 are still tillering but are nearing the jointing growth stage. Wheat that had begun jointing prior to the April 9 and 10 freezes may have suffered damage to the developing wheat heads and stems especially if no snow cover was present when the temperature lows occurred. Cutting open the stems of the oldest (largest) tillers can help determine if any damage has occurred. Healthy plants will exhibit cream or light colored internal plant tissues. Discolored or brown colored internal plant tissue indicates dead plants. Wheat plants I’ve looked at in Logan and Morgan counties are still healthy.
Another symptom of cold temperature damage is white wheat heads and stems. White heads appearing later in spring are the best measure of how April colds affected wheat.
Weather forecasters are predicting warmer than normal temperatures this summer west of the Missouri river. Therefore, we should see a fairly rapid greening up of both wheat and alfalfa.
Cold soil temperatures and wet soils have also hampered planting corn and sugar beets. If the weather forecasters are right, Planting longer season corn varieties is still a sound decision even with a late planting. Plant corn when soil temperatures return to 50 degrees Fahrenheit.
Moisture from winter and early spring storms have been very favorable for the northern Front Range and South Platte valley. The South Platte communities from Kersey to Sterling have received from 2.66 to over 3.13 inches total precipitation this year. Greeley, Iliff, and Crook weather stations have recorded less total precipitation: 1.44 inches, 1.78 inches, and 2.32 inches, respectively.
These same storms have missed much of the high plains south and east of the South Platte Basin. In this area, Akron and Holyoke have received the most: 1.43 inches and 1.38, inches, respectively. Farms south and east of there have missed many of these storms getting just a fraction of the moisture during this same period. Yuma, Wray, Burlington, Stratton, and Last Chance weather stations have received less than eight tenths of an inch this year.
Dryland winter wheat fields in the High Plains region and further south are struggling to survive. March and April precipitation has helped fields located in the South Platte basin to catch up to seasonal average soil moisture reserves after the lingering effects of the 2012 drought. The lack of precipitation for this same period south and east of the South Platte Basin has further resulted in droughty soils. The freeze injury on the wheat plants is only part of the challenges that fields in this area have to cope with.
Making matters worse for the High Plains farmers is that while wheat is their No. 1 crop the continued drought may prevent them from planting corn, millet, sunflowers and other summer crops unless they get favorable rains later this month through early June.
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