Good soil is one which has

Good soil has 50% organic and inorganic salts and other 50% of pores, air and water.
Soil consists of these major components of inorganic mineral matter, about 40 to 45 percent of the soil volume. organic matter, about 5 percent of the soil volume, water and air, about 50 percent of the soil volume.
A typical soil is about 50% solids (45% mineral and 5% organic matter), and 50% voids (or pores) of which half is occupied by water and half by gas.