Duane A. Lienemann,
UNL Extension Educator, Webster County
September 8, 2012 Edition
Well we are we deep into corn harvest and we are finding pretty much what we expected. Some fields are not yielding very well, while others are yielding better than anticipated but, all in all, the comments I have been getting is that it is all over the board for yield, test weight and moisture. It is no secret that the biggest loss has been in our dryland fields and some pivot corners. I know that a lot of these fields were put up silage and for good reason. That may be one reason we have not seen the aflatoxin coming in with the loads of grain to the elevators. That is the good news for us in South Central Nebraska - we have not had the aflatoxin problem that I and many others first anticipated.
Those that didn’t ensile their corn are seeing anywhere from 25% to 75% drop in yields from their normal yield average. It seems that some of the fields that looked the best going into harvest and even had healthy looking green plants going into mid-August are the ones that really are showing the yield deficit. I would assume that has something to do with pollination or the season classification of the seed planted or perhaps hail events. I have not heard much from the irrigated fields as many of them are just now being opened up. There are however some worries about pollination failures in some fields. There is also likely to be some areas where we had the hail storms that will have some yield concerns.
Those farmers who cut their suffering dryland corn several weeks ago for silage are now having some concerns. I have been getting some questions now about the possibility of aflatoxin in silage from corn that may have had it when they cut the corn for silage. That is an interesting question and not really an easy one to answer as the answer would really be in the form of a couple of questions. Was there evidence of “aspergillus” ear rot or mold on ears of corn? Was there evidence of ear worm or perhaps other insects feeding and exposing the ends of ears early on? If you know the answers to that, than you may have a good handle on the potential. If you are not sure, it may not hurt to do some testing. I know some producers thought that making silage would help. While that is true for nitrates, it is not necessarily true for aflatoxin. Ensiling corn usually does not reduce aflatoxin concentrations, although unlike infected stored corn grain - silage concentrations of the aflatoxins are unlikely to increase in properly managed silage.
As I visited the local co-op for my morning coffee this week I had several comments and questions about the large amounts of “black dust” being kicked up during harvest, particularly in the dryland fields and/or pivot corners. Evidently combines are coated with black dust after only one pass through the field. Even in fields that look "normal," there are often pockets where black dust fogs from the header and straw chopper as those areas are harvested. These dust clouds are being described as reminding them of soot from a fireplace or stove. Farmers have also made note of black stalks or black/gray discoloration or dusting on the surfaces of the corn plant leaves, shucks and even stalks. What is this stuff? According to Cropwatch.unl.edu much of this black to gray dust-like material is made up of large quantities of microscopic spores (reproductive structures) produced by fungi, in addition to the normal dust created during harvest. These fungi are not the “mushroom” fungi that most people may be familiar with. Instead of producing their spores in a mushroom, these fungi produce spores on the surfaces of plant material, giving it a sooty appearance that can be rubbed off. The most common fungus that causes this sooty mess is “Alternaria spp”. This fungus is a common microorganism in the soil that acts as a common saprophyte that grows on dead plant tissue to promote the necessary degradation or breakdown of the plant material to return to the soil. It is likely that recent showers and the mornings with dew have promoted the rapid and simultaneous production of spores that have been reported on the dried corn plants prior to and during harvest. My guess is that a lot of our corn stalks will have a dark color to them as we turn cattle out after harvest.
While it makes a mess of headers, windshields and combines and may even cause fires, it might also be a good idea to be cautious of the black dust. While most of the dust is annoying, it is mostly harmless; however, it is good to remember that any dust in high density can cause problems for folks with allergies or respiratory problems. Since most farmers over the age of 30 have dealt with cleaning musty grain from grain bins at some time, most farmers have some degree of sensitivity to grain dust and molds. It may be a good idea to use a respirator or at the very least a disposable dust mask that fits over the nose and mouth. You may also want to remember that the same conditions that encouraged the growth of saprophytic fungi also favored the development of a lot of other molds and fungi. Some of them can make a person sick.
I have heard of farmers who have already experienced the chills, fevers and muscle aches associated with "dust flu" after they were exposed to black dust while harvesting corn. It is also possible to develop a rash on arms or other exposed areas where a lot of the black dust can coat exposed skin. Even if nobody gets sick from the black dust, I understand that it's playing havoc with air filters. Not only do cab and engine air filters plug quickly when exposed to that stuff, but it's so fine and organic that it's very, very difficult to blow out of the filters. If you're noticing poor ventilation in your cab, or your engine is short on power, make sure your air filters are as clean as you can make them. While you are at it you might consider switching cab filters from standard filters to special "allergy filters" that are designed to stop mold spores. With the type of growing season we have had so far, there is no sense in taking a chance at even more complications.
The preceding information comes from the research and personal observations of the writer which may or may not reflect the views of UNL or UNL Extension. For more further information on these or other topics contact D. A. Lienemann, UNL Extension Educator for Webster County in Red Cloud, (402) 746-3417 or email to: dlienemann2@unl.edu or go to the website at: www.webster.unl.edu/home
No comments:
Post a Comment