The scenario is as follows (and no, this is not homework, it was shown to me by a consultant):
A crude oil pipeline ROW runs under agricultural lands in mid-Alberta. The portion of the field where the ROW is is green, while the rest of the field is yellowing and not as healthy.
Why?
There are obviously multiple possibilities. A few have been proposed are temperature of the pipeline (all but totally ruled out as a possibility), soil compaction, and salts.
What makes grasses grow better and how could that relate to this situation?
Could it be a different type of soil, in the trench along with the pipeline? Sometimes the native soil is unsuitable for bedding material - if a different type had been hauled in and used, perhaps that’s it.
What’s the weather been like? Is there any correlation between the pipeline trench and water transmissivity?
I would have thought that the temperature difference would count - how was that ruled out?
Could it be a different type of soil, in the trench along with the pipeline? Sometimes the native soil is unsuitable for bedding material - if a different type had been hauled in and used, perhaps that’s it.
Native soil was used and was supposed to be replaced at the same compaction percentage.
What’s the weather been like? Is there any correlation between the pipeline trench and water transmissivity?
There could be, but I should add that this is a small portion on a very long ROW where construction was done. It seems the green suddenly starts, then stops, along the ROW and no where else along it.
I would have thought that the temperature difference would count - how was that ruled out?
It’s 1.5 meters belowground and it’s not a hot pipeline.
I was sent a few pictures and some more information this morning which I’ll post momentarily.
As you can see the barley outside the ROW is fairly ripe and the barley on the right-of-way is still very green, there is a fairly distinct line. You have indicated from our past experience that the soils in this area of Alberta can take up to 3 years to produce at past production levels. This is about amount of time that has passed since we completed this pipeline.
Why do you say “the rest of the field is yellowing and not as healthy”? (emphasis added) The areas away from the pipeline have obviously matured faster, but unless there’s data you’re not sharing I don’t see what’s unhealthy there. The yellower parts of the field look like a perfectly healthy mature barley crop to me.
I’m going to guess that when they refilled the trench they either got more or less topsoil, or the topsoil they were putting back on top had gotten some clay mixed in, or something. Perhaps it’s a bit heavier and retains more moisture, resulting in slower maturing during a hot spell or something. Really there’s next to no way for the pipeline itself to have any effect on things. Temperature, I guess, as mentioned, but the slower maturation rate would indicate a lower temperature rather than higher. At 4 feet below the surface I have a hard time believing it would have any impact. The obvious possibility is that the trenchers weren’t careful enough in replacing the topsoil.
Ok … I think that what the email was saying is that most of the barley has matured while that green patch has not. So it’s not that the brown part is unhealthy, but that the green part has not matured.
It’s a short patch? Occurs nowhere else along it? Hmm… perhaps the fertilizer rig quit momentarily right there .
It seems a stretch to think the pipeline is the cause of it.
Assuming the soil and temperature are the same throughout the field, the only two things that I can think of are moisture and nitrogen.
It’s possible that mositure collects around the pipeline (why in that area and not in another, I don’t know). The plants can tap into that moisture which could extend their growing season.
Alternately, the pipeline could be giving off nitrogen (perhaps through tiny fissures) that acts as fertilizer, keeping the plants greener longer.
Is the barley in that one row the same variety as the surrounding crop?
ETA: Either more moisture or more nitrogen should make that section of the crop bigger and robust than the rest of the barley.
Having worked in the pipeline industry for a number of years I can venture some comments.
After the line is laid,the backfill is screened so no large rocks impact the pipe.Unless the landowner has been litigious,no special care is taken to be sure the fill is replaced in order,though restoration of “topsoil” usually takes place.Foreign (off site ) fill can be used.
Natural gas lines have a surprising amount of latent heat-I often heard reports from line walkers of badgers,groundhogs,etc. living on the pipe surface,with corresponding concerns of “dope” degradation.(corrosion protection)
Product lines,i.e. liquid,are often warm,with heavier grades of crude sometimes heated by steam or other trace,and insulated.Cessation of heat=cessation of flow in some cases.
It is very unlikely the line is leaking nitrogen.
Cathodic protection is almost surely in place on a major transmission line,especially traversing private property. I am unable to make any conjecture on its relationship to plant growth.
Cathodic protection is an absolute requirement here, btw.
So I guess the general consensus is that it must have something to do with compaction and/or how they replaced the soils in this area. It’s odd, though, that this issue isn’t run into more often.
And to clarify, I definitely shouldn’t have said ‘less healthy’.
.
