UNL CropWatch Sept. 19, 2010: Early Freeze Causes Spotty Damage in the Panhandle

UNL CropWatch Sept. 19, 2010: Early Freeze Causes Spotty Damage in the Panhandle

Sept. 10, 2010


How Low Did it Go?

Following are some of the lows reported at weather stations near the reporting towns in the Nebraska Panhandle Sept. 7. Temperatures are from open areas and would not reflect the localized environments under crop canopies.  (Temperature data provided by Al Dutcher, Extension State Climatologist. See full temperature and precipitation data for Sept. 5-9.)

Alliance 30
Bridgeport 28
Broadwater 29
Bushnell 31
Chadron 30
Champion 29
Curtis 37
Dickens 32
Harrisburg 24
Harrison 28
Kimball 29
Lodgepole 34
Madrid 35
North Platte 32
Scottsbluff 32
Sidney 31

On Tuesday morning (Sept. 7) temperatures in areas of west central Nebraska and in the Panhandle dropped to the upper 20s to low 30s. While crop damage was not widespread, there were pockets of damage, as indicated in the following reports from educators and specialists in the region.

Bill Booker, Extension Educator in Box Butte County: Frost damage was spotty here with temperatures at or close to freezing twice in one week. In Box Butte County dry beans planted late could see some yield loss and hopefully no loss in quality except that some dry beans could be smaller than normal. Corn here is about two weeks to black layer, and the temperatures caused little concern. The sunflower crop is in good shape and is relatively safe to frost. Typically, temperatures would need to be at 24 degrees for two hours to freeze or kill the plant. Until this occurs, the plant is striving to reach physiological maturity, indicated by the back of the head turning yellow and the bracts turning brown. When the bracts are completely brown, the seed moisture could be in the low 30s, which is important to know if treating with a desiccant. To be sure, check the moisture content using a scale and oven.

This was a good week for crop development. Generally, temperatures were good and we received ½ inch of rain Thursday night. This rain could be a help or a challenge to the newly planted wheat, but it will help improve conditions for those just starting to plant. Soil conditions had been extremely dry on the surface with good moisture below. The last half of the summer has been dry so getting surface moisture was a big help. Some growers have held off planting wheat in order to reduce the risk of grasshopper feeding.

Karen DeBoer, Extension Educator in Kimball, Banner, and Cheyenne Counties:  In our area, much of the proso millet is swathed and is being harvested so the cold temperatures aren't likely to have affected it. Much of the dryland corn is shutting down and also isn't likely to have been hurt by the cold.

Some producers here are concerned about getting a rain on their newly seeded wheat. On tilled summer fallow fields, the surface is dry and powdery. There was moisture just below the surface to plant into. If we get rain, they may have to re-seed if a crust develops.

Jim Schild, Extension Educator in Scotts Bluff County: Later planted dry beans are apt to show some frost damage from Tuesday’s lows. I was looking at one of our fields this morning (at the Panhandle REC, Scottsbluff) and the top leaves of the dry beans were frosted, but the pods appeared to be okay and were still green. The low reported here was 36. The sugarbeet crop will tolerate frosts and freeze. For those cutting corn for silage though, the freeze damage is playing havoc with the silage cutters as they try to harvest the fields before the leaves drop.

Drew Lyon, Extension Dryland Crops Specialist, Panhandle REC, Scottsbluff: Proso millet is already being harvested and I wouldn’t expect any serious injury to the crop. Dryland corn here had already started drying down due to dry conditions and likely wasn’t affected by the low temperatures. I heard some reports of serious frost injury in corn and beans west of Alliance, in the Pumpkin Creek region of Banner County, and in eastern Wyoming

Jeffrey Bradshaw, Extension Entomologist at the Panhandle REC, Scottsbluff: The dry beans here appear to have escaped damage from the lows, however, I did see a couple freeze-dried corn fields in Banner County.

John Smith, Extension Machinery Systems Engineer, Panhandle REC, Scottsbluff: We had two frosts here so far, one on Sept. 2 and the other on Sept. 7. I drove through the crops country between Scottsbluff and Hemingford via Alliance and Bayard this week to look at plots in growers’ fields. A lot of the crop did not have frost damage, but as much as 40% of the bean crop was still green and had some frost damage. In most of the fields with frost damage the top leaves were frosted. I don't think that will hurt much because the pods are below that and I don't think many of those fields were cold enough to freeze through the pod to cause damage to the immature bean seed. Two growers I talked with said they had fields where some pods were damaged. Probably at least 30% of the bean crop is already out of the field, and another 20% or so is ready to cut or has been cut, so all of that will not have been affected.

I don't think sugarbeets were "hurt," but since they are a biennial plant, cold periods tend to "tell" the plant to convert from year one to year two and thus change the composition of "sugars" in the plant. A hard freeze at this time or prior to mid-October or so is really bad, but this will just tend to speed up the natural process. It did not help the crop, but should not have affected sugar content to a large extent.

I did see several corn fields where the leaves were "white" from the frost at least down to the ear. I saw several other corn fields where the top leaves were frosted. That is not good if the corn will be chopped, but I think most corn is far enough along that at the worst, it will affect drydown and maybe test weight a little.

These frosts came a bit early for us, so I hope we don’t see any more too soon.