Corn Field Growth Pattern

Factual Questions
1

I pass several corn fields on my drive to work. I have noticed that rather consistently, the corn stalks are shorter in the corners of the field. The effect makes it look like a ramp from nearly ground level high plants to the full height of the normal stalks. Sometimes there are shorter plants on the straight edge of the field, but not as consistently.

Why? Why don’t the corners grow as well? Erosion? Farmers skimping on fertilizer? Shade from non-corn plants? I would like to note that there is generally not much slope to these areas and I have observed the effect even in areas with no trees around it, which tend to discredit the erosion or shade. More weed interference? If it were weeds, then you should see just as much growth retardation around all edges, not just corners.

2

I should also note I have not seen any equipment for irrigation in any of these fields, but that doesn’t mean there isn’t any. It might just not be overly visible.

3

My guess is that you’re seeing the effect of a center pivot irrigation system. Water is pumped from the middle of the field through an overhead boom that pivots around the center. Obviously, the corners don’t get much water.

4

Thanks…, that may be it, but I am attaching a link to an aerial photo of the area so you can see that these fields don’t seem to be square enough for that kind of irrigation - they are mostly very thin rectangles… it could be irrigation, but not that type?areial view of fields in question

5

If the farmer applied fertilizer to the field it will be depleted by runoff, which is more severe at the edges of a field than in the center.

6

Your link doesn’t work for me. Please post again.

You could get the same effect with a linear system since the end of the boom doesn’t spray as much water as the middle. Could also be due to competition from weeds; the corners are especially affected due to exposure from two sides. We can only speculate without knowing more about the field in question and the farmer’s agronomic practices.

7

I used to notice this too, driving in Iowa with relatives.

WAG:
Planting and pesticide and fertilizer application involve tractors etc. that don’t turn corners tightly.

8

emily: That’s a good explanation. If the edge has a scallopped pattern, you can blame the tractor.

9

Another cause could be compaction. If the wheel tracks passed over the same spots year after year (which seems reasonable at corners) the topsoil could get packed down over time, making it harder for the roots to penetrate, causing plants that don’t develop as well.

10

Obvious post:

Its probably a combination of all the above factors.

11

Plants at the edge of the block are exposed to wind - wind rock can cause the roots to loosen and this can stunt the growth, wind also causes the plant to lose more moisture and if this cannot be replensihed quickly, the plant will wilt a little and this can stunt the growth or cause premature flowering.

Furthermore, plants in the centre of the block have more competition, so they tend to grow taller and straighter; they are less exposed to wind and the humidity can be a little higher there, promoting lush growth.

As to why the corners are more stunted than the edges; they are exposed to wind from two possible directions, whereas the edges are exposed only to one.

Plus some of the other factors people have already mentioned.