4 Conditions that Affect Soil Air Composition
The following are some of the conditions that affect soil air composition;
1. Organic Matter and Biological Activity in Soil
In tropical soils, there is a rapid evolution of carbon dioxide, CO2, by the highly active biological population especially soil micro-organisms which decompose organic matter at very fast rates. This trend affects the concentration of both oxygen (O2) and carbon dioxide (CO2) in soil air.
The microbial decomposition of organic residues accounts for the major portion of the carbon dioxide CO2 evolved. During the process of respiration and decomposition, oxygen O2 is used up while carbon dioxide CO2 is evolved.
Other important biological activities which influence soil air composition are respiration by high plants and the continuous contribution of their roots to the soil biomass.
Read Also: Movement of Nutrients in Soil Moisture and Measuring Soil Water
2. Soil Type and Soil Depth
Carbon dioxide, CO2, increases with soil depth while oxygen O2 decreases with depth with the heavier soils becoming more deficient than the lighter textured soils in the subsoil layers.
3. Soil Moisture and Temperature Required
Marked seasonal variation in the composition of soil air could also be attributed to soil moisture and temperature differences.
High soil moisture especially during the rainy season usually results in low oxygen O2 and high Carbon dioxide CO2 levels in the soil air. During the dry season, there is more circulation of air in the soil and O2 levels are usually higher than Carbon dioxide CO2.
4. Application of Manure
The rate of Carbon dioxide CO2 production could be increased through the application of farm yard manure (FYM) especially when the soil is wet and the rate of diffusion of oxygen O2 and Carbon dioxide CO2 slows down.
Green manuring (especially from fairly succulent crops such as Leucaena and Gliricidia spp.) could increase the Carbon dioxide CO2 content of soil air.
This can lead to poor germination of seeds sown too soon after a green manure crop has been plowed in.
Read Also: Status of Soil Aeration and Oxidation-Reduction (Redox) Potentials (Eh)
