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Driftless SW Wisconsin | I don't like the idea of criticizing a researcher based on a conversation "5-6 years ago".
I heard the same (I believe) researcher speak and what I recall from the conversation is that we do not necessarily have to apply all of the chemical elements removed by a crop with artificial, man-applied replacements.
I am an engineer, not an agronomist, but what I recall from him and other speakers is that those nutrients can and do also come from many other sources in addition to what we apply. Soils and minerals are generated by nature, maybe just not at the rate that 200 bu corn requires so we need to supplement. Earthworm activity can convert a number of materials to nutrient elements.
Banding is just a more efficient way of applying nutrients where they are needed. Broadcasting leaves fertilizer on the surface where some of it volatizes in tot the air, washes into the watershed or is driven on and in such a compacted mass that it is probably not available to plants for quite some time.
Broadcast recommendations as I recall were based on a certain degree of loss and reduced availability.
I have heard several researchers from several different Midwest universities say that IF fertilizer is placed beneath the soils surface by 2" or more losses due to volatization into the air or runoff into water table are greatly reduced.
I also agree with the other poster who points out that the vast majority of root mass of corn APPEARS to be in what we call the root ball area. Maybe 10" diameter. Therefore locating that fertilizer relative to the plant rather than out in the middles and especially for the less water soluble nutrients, would seem to be more efficient and less wasteful of fertilizer.
The proof is really in the execution. I know of several of our strip till customers who are raising excellent corn with much lower than the old standard broadcast rate recommendations. And they have been doing this for a number of years.
Nitrogen being very water soluble tends to leach out of useable areas as we have all seen at one time or another. Fall applied nitrogen has traditionally been heavily applied at times to make sure there is enough there when the plant needs it next summer. In some soils a good portion of this N is lost to the plant. "Reduced" rates from historical rates are obviously possible IF the N is indexed to the plant in time and space (location). We see even very typical "conventional farmers in Illinois going to split applications of N (28/32 or NH3) and often with some 10-34-0 because their experience has shown that you can reduce the amount of product used by more than enough to pay for the extra trip to side dress corn.
My "bottom line" is similar to yours - nutrients removed by the plant need to be replaced. However that can be done much more efficiently with less producer-applied product than required in the past. Nature can also provide much of what is removed if we provide the environment for natural functions to operate. Leaving residue on the surface is one way we can help those natural functions.
jmho.
Jim at Dawn
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regarding the strip till below
