Interesting graph. In KY, after ~4 years of No-Till, those soils will hold 1 to 2 inches more water than tilled fields during the growing season. For us, that can be the difference in great yields. No-Till = Soil Conservation AND Water Conservation.
The value of residue. This is the difference between no-till and high conservation tillage treatments here. A positive number shows that NT has more moisture than Tilled and a negative number is the opposite. Look at the weekly movement in the upper 3 feet of the profile.