The best bentgrass, bermudagrass and seashore paspalum playing surfaces will be produced when the soil has just enough water to keep the grass from wilting and the remaining soil pore space will be flled with air.

I wrote about this, and how it can be accomplished, in a column for GCM China. 

Measuring soil water to estimate soil air 

测量土壤水,估算土壤空气