Duane A. Lienemann, UNL Extension Educator, Webster County
October 6, 2012 Edition
Last week I centered my discussion on the value of corn stalks as a resource for cattle feed. I was not surprised when I got several responses back with comments that I knew would come, but had hoped wouldn’t. It is obvious that there is disconnect between our crop producers and our livestock producers when it comes to this valuable resource. It seems that more and more grain crop producers are electing not to make their stalks available to cattlemen for grazing. Where we have so many acres of corn and milo stalks and soybean residues that could provide feed for our livestock, it is a shame that so many of these acres will be just left or worse yet disked under.
I know that some crop consultants and seed corn representatives tell their farmer clients that grazing cattle on these stalks is “bad news” for those fields and that it may adversely affect next year’s fields. I know that several years ago animal scientists at the University of Nebraska-Lincoln debunked that. It was good to see that this study was researched again and that pretty much the same conclusion came from the results of the study. Let’s take a closer look at this controversy.
Many producers who could graze residue cite the need to maintain at least 30% ground residue cover as a restriction. This plant residue reduces soil erosion during the winter until the establishment of the new crop. I understand those concerns; however, grazing residue is still possible since animals seldom consume more than 25-35% of the residue. Since a 120-bushel-per-acre grain yield should also produce 6,000 pounds of residue, the removal of 1,500 pounds should allow for a sufficient amount of residue remaining to provide the required cover. This is especially true where adequate stands of taller-growing corn hybrids were grown and livestock grazing is limited to consumption of un-harvested grain, leaves, and husks. These plant tissues generally decompose rapidly and are not present in large quantities the following spring.
I know – the biggest issue out there for corn farmers is soil compaction. It too is also cited as a reason not to graze corn residue. Livestock can cause soil compaction, but the compaction they cause is generally shallow. Producers concerned about compaction could graze the residue immediately after harvest, removing the livestock after 60 days to allow the soil's freeze-thaw action to minimize surface compaction. Producers should pay attention to the soil types of the crop fields and remove livestock when the fields are muddy. It is obvious to me and should be to most everyone else that compaction is essentially a non-issue at this point and likely through a freeze because of how dry we are. You don’t have to be an agronomy professor to know that there is very minimal compaction after the ground has frozen. However the best grazing of course is right after harvest and usually before a freeze. With an open winter however, that is an option that many corn producers may be open too if compaction is their main concern. I might note that growing no-till soybeans after grazing corn residue may require more management to minimize compacted paths and water-filled hoof tracks.
Studies in Illinois, Iowa, and Nebraska indicate that soil compaction from cows grazing corn residue is limited to the top 6 inches of soil. Shallow compaction can be corrected by the freeze-thaw action of the soil in no-till situations and disc, chisel-plow in conventional tilled fields. The two main factors that affected the severity of compaction were soil moisture and soil type. In each of those studies, no significant difference was found in the yield of the soybeans following the residue grazing, even using no-till. In fact UNL research from 1996 and again in 2011 showed the effects of fall and spring-grazing on subsequent corn and soybean yields. The yield of the following soybean crop was increased by around 2 bu/acre with fall-winter grazing and 1.3 bu/acre with spring grazing compared, with no grazing of corn stalks. Yield of corn as the second crop after grazing was not significantly affected resulting in an average of 1-3 bu/ac yield increase depending on fall or spring grazing. I might ask, where do these crop gurus get their information that grazing stalks drops yields?
I also know that controlling livestock is another issue that concerns many crop producers. Fencing around many crop fields has been removed for various reasons. Portable electric fencing that can be removed before field work begins is an attractive option. The use of single-strand electric fencing may be the least expensive method for controlling livestock; however, location should be taken into consideration when determining the type of fencing to be used. Liability is always a concern with pastured livestock, but to me fencing is really a very small problem.
I think we need to discuss the potential benefits for the crop producer. Grazing stalks have been shown to have benefits for subsequent crops. Cows grazing cornstalks for 60 days will remove approximately 30 percent of the residue which is digested and returned back to the field. If residue is left in the field to nature, nutrients are lost to wind and weathering. With that in mind, relatively no organic material is lost to a field when grazed. Now add to that to the fact if supplemental feeds are supplied to cattle like protein tubs, alfalfa bales, or other roughages/feedstuffs, more nutrients may be added to the field than what are removed. You might also consider that residue buildup has been a well-documented problem in many corn-on-corn fields with new hybrids and grazing removes these problems. More importantly, cows deposit nutrients in the form of manure back on the field. These natural fertilizers are readily available for the crop and are a natural source of nutrients. As they graze, they also reduce volunteer corn, considered a weed and a yield-robber in soybean fields. If you ask me, we would all be better off if our crop producers would help the livestock producer and we all would benefit!
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: http://www.webster.unl.edu/home
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