Confusion on the last slide in lecture 9

For the last slide in lecture 9, I'm a little confused about the different graphs. As far as I can tell, sand has a lower AEV than the rest of the particle types because of the larger pore size, which makes it easier for water to drain, requiring less tension for water to leave the pores and air to exit. However, I'm confused about the graphs for aggregated clay and massive clay. I'm unsure why the AEV is larger for massive clay. I'm guessing it has something to do with massive clay having less pore space?

1st Dexter, be careful with lower versus higher AEV. The graph indicates matric potential (which is negative), and you indicate tension.

As the graph shows matric potential..... In the sand, AEV corresponds to a higher matric potential i.e. closer to zero; and as you indicate this means that there are larger pores in the sand (i.e. they drain at a high matric potential). Additionally, as the curve drops at high matric potential and is steep, this indicates that most of the pores are large.

Comparing massive clay and the aggregated clay. What is the difference in pore size distribution in the aggregated clay compared to the massive clay (and why)?