Soil Aeration on Biological Activities and Plant Growth: The composition of soil air affects the activities of soil micro-organisms, nutrient availability to plants, respiration, and nutrient uptake of crops.
Aerobic soil microorganism absorbs free oxygen O2 through the very efficient cytochrome oxidase enzyme system. This aerobic activity continues in the soil when the O2 concentration is not less than between 3 to 6 x 10-6M.
The concentration of oxygen 02 in soil solution when in equilibrium with air at 200 to 250C is 2.7 x 10-4M which is between 60 – 100 folds larger than that of the soil.
Aerobic metabolism continues until oxygen O2 concentration in the soil falls below the figure corresponding to a partial pressure of 1% of the pressure of Carbon dioxide CO2 in a free atmosphere.
Adequate soil aeration and temperature are essential to soil environmental factors that strongly influence the performance of plants and soil macro-and micro-organisms.
Adequate soil oxygen makes oxidation reactions proceed while a low level of oxygen leads to reduction reactions.
The products of oxidation reactions are useful to plants while reduction causes the formation of methane (CH4) and the reduced forms of nutrient elements which may become toxic to plant roots. Traditional farming practices such as heap making and ridging ensure adequate soil aeration.
Most tropical crops perform best within the temperature range of 200– 350C. Soil temperatures are regulated by the use of mulch, regular water supply, soil tillage, and the establishment of vegetation cover.
Read Also: Status of Soil Aeration and Oxidation-Reduction (Redox) Potentials (Eh)
