What is Soil Aeration

Whatever may be the structure of aggregate, it introduces pores in the soils. These pores are filled by air and/or water and have a role in the plant growth. Since plants breathe through their roots and if pores are not there, oxygen may not be available to them to breath and they may die. Therefore, the process of soil aeration is one of the important determinants of productivity. The presence of pores in soil changes its density i.e. the bulk density and the particle density. Bulk density, D_b of soils is defined as the mass per unit volume of soil consisting of soil particles and pore air. Particle density, D_p of a soil is the mass per unit volume occupied by soil particles alone and is expressed as grams per cubic centimetre or as megagrams per meter cube. Since the particle density depends upon the chemical composition and crystal structure of the mineral particles and is not affected by pore space, it is generally taken to be 2.65 g cm^{- 3} or 2.65 Mg m^-3.