ABSTRACT
Soil is composed of solid particles (minerals and organic matter) of different sizes, usually
bound together into aggregates by organic matter, mineral oxides, and charged clay particles.
The gaps between the particles are linked together in a complex network of pores of various
sizes. The total pore space of a particular soil consists of pores existing both between
adjacent soil particles and between soil aggregates. Through this pore space the soil
exchanges water and air with the environment. The movement of air and water also allows
for heat and nutrients to flow. The number and size of pores vary considerably among soils
exhibiting different organic matter content, texture, and structure.