I have to respectively disagree with you on this one Bud. While we are all familiar with the pre-war annual maneuver photos, such as the example that you have posted above, along with a myriad of other photographs that were published during the war as having been taken in combat, this film footage is IMHO quite different.
I would suggest that we are all familiar with the "live fire" drills where soldiers in training crawled under barbed wire entanglements while machine-guns spray live rounds back and forth a few feet above the entanglements to help prepare the trainees for the day that will eventually come when the machine-guns will be fired at them rather than above their heads.
With that said, the explosions in the film footage look awfully large for a training exercise? I'm guessing 155's to 240s for the larger explosions. A bit much for a training exercise, don't ya think? And if it were a pre-war training exercise, why the lunar landscape that was so typical of No-Man's-Land when everyone expected the war to be one of maneuver that would be over before Christmas of 1914? I don't ever recall there being any pre-war maneuvers that featured trenches and barbed wire entanglements? Or gas shells, which appear in the form of white clouds rather than dirt and dust that drift across the ground following relatively small explosions.
The vantage point of the camera could easily be from a concrete emplacement on high ground overlooking the front. The Germans held the high ground along most of the Western Front after the race to the sea. While I don't believe that the footage is necessarily from the Somme, it could be from any one of a number of different engagements, large or small, that took place at regular intervals along the Western Front over a four year period.
Just my $ .02 worth based on having viewed lots of WWI documentaries that have tended to "borrow" film footage from the war, before the war and via Hollywood shortly there-after.