Fig. 4. Cumulative density functions for the cumulative probability density function P(E E_i) vs. specific rupture energy E before and after normalization of E to the air-dry state [E(w/w₀)] for Maury Block 2 data: (a) moldboard plowing and 0 kg N ha^–1 yr^–1 treatment (MP-N1), (b) moldboard plowing and 336 kg N ha^–1 yr^–1 treatment (MP-N4), (c) no-tillage and 0 kg N ha^–1 yr^–1 treatment (NT-N1), and (d) no-tillage and 336 kg N ha^–1 yr^–1 treatment (NT-N4).