Nick,

Cows grazing corn stalks is a pretty common practice in Iowa for several reasons. First it is very inexpensive feed for the cow herd for a month or two in the fall. Second it removes some of the stover and most of the dropped grain to benefit the grain operation. Less dropped grain results in less weed pressure the next year, and less stover is preferred by no-till farmers the next year to allow the soil to warm up faster in the spring.

We did a webinar a couple years ago that explains this in much more detail here https://www.youtube.com/watch?v=KSwCB7xV4SE

In terms of impacts on the soil, there has been some research as discussed in the above video that the impact of cows, manure, etc increase the biological activity in the soil.

One of the bigger concerns is if the cow grazing increases compaction. One of my cohorts did a study a number of years ago looking at soil compaction. I’m attaching a copy of that project summary. His summary was that there is no negative impact from grazing provided cows are removed prior to the thawing of the field. The video above from Nebraska supported that also. There can be an increased level of pugging on the soil that might require more down-pressure on the planter.

In terms of nutrient replacement, there is a good publication at https://www.extension.iastate.edu/agdm/crops/html/a1-70.html . Basically when all the stover is removed by baling stalks, that N,P and K needs to be replaced with fertilizer. When grazed most of the nutrients removed by the cow are also replaced by the manure, and very little is actually lost. In most cases there is no need for additional fertilizer when grazed, however regular soil testing is still advised for optimum fertilizer application.

I hope this helps answer your questions. By far, the majority of cattle producers do graze corn stalk residue for these reasons. If you have more questions feel free to contact me. I office in Vinton and my email is <personal data hidden> and my phone is<personal data hidden>.

Denise