There's a common refrain heard during many basic training classes and bayonet courses:
Blood! Blood! Blood makes the green grass grow!
Well, it's not just a macabre and motivational saying. It's also completely true.
Blood may seem like a bad garden additive since it has plenty of salt, but its salt content is actually manageable when it is diluted into water and mixed with soil. Meanwhile, it has lots of nitrogen which is important to plants' overall growth and color.
That's right, it doesn't just make grass grow, it makes it grow green.
Another good feature of impaled enemies in terms of plant growth is their bones, which provide phosphorous, an important nutrient for healthy roots.
Both bones and the red stuff are fully organic, though vegetarians have been known to complain about produce grown with meat products.
Of course, while limited bayonet charges in a garden may provide plenty of fertilizer for the plants without causing too much destruction, full-scale battles do more harm than good.
Explosions and metal fragments destroyed large swaths of the European countryside in the world wars. Tanks driving over mushy fields can create long-lasting scars as the ground is torn up. Burning fuel and oil from destroyed vehicles poison the ground.
Still, it's pretty great that the drill sergeants or instructors making recruits yell out, "Blood! Blood! Blood makes the green grass grow!" are actually teaching something.