Enough to make a man become a vegetarian.

When I did custom garden tilling in Illinois back in the 70s, I offered soil testing and then recommended soil amendments to correct deficiencies.

I recommended blood meal and bone meal to one customer, but they were vegetarians and did not want me to use those products. I told them they were not eating the blood and bone and that it broke down and released Nitrogen and Phosphorus. But they would not listen so I had to make substitution.

I used Spagnum Peat for Nitrogen and told them they had to wait two weeks to plant seeds since as the peat started to decompose it would rob Nitrogen from the soil before releasing it back.

And that wait just might affect the seed bed the tilling provided. Rainfall could cause the soil to become matted down.

You win some and you lose some. ;)