So I've been re-reading some military history lately and I can't help but notice that the distinction between "total war" as we know it and earlier "scorched earth" warfare seems rather thin. For example, just as the World Wars and Cold War preparations for WWIII emphasized total economic mobilization, warfare against the whole enemy society and economy, and massive mobilization of manpower - (as far as I can tell) so do wars in much earlier times. Rome in the Second Punic War, both sides in various wars between nomadic tribes and frontiersmen worldwide, and both sides of the last Roman-Sassanian war seem to exhibit these traits. Is it micromanagement of the industrial economy which sets them apart?
Total War is when you have all aspects of your economy go towards fighting your enemy. This can include things like converting your factories into ammunition factories, putting a ration on oil, or trying to sell your populace war bonds. The US home front during WWII was a great example of this.
Scorched Earth is a bit more offensive in nature. You would have your soldiers burn and destroy the land around them (whether it is your land or theirs) then retreat. The enemy's army will not be able to scavenge supplies from the land after your retreat, stretching their supply lines thin. With thinner supply lines the the enemy will either receive supplies less often (lowering morale) or send more caravans to compensate (wasting resources). The Russians used this to good effect during their fight with Napoleon.
Edit: These probably seem so close in your research because these are more concerned with the logistics of war rather than the strategy that most people think of. I can't remember where I heard it but a novice focuses on strategy. An expert focuses on logistics.