The soil atmosphere is of utmost importance for oxidation processes. Tillage and plant cover are fundamental. Soil supports plants and serves as a reservoir for water, air, and nutrients.
Soil porosity
Depending on the soil composition, there will be varying amounts of empty spaces that make up the porosity.
This porosity can consist of:
Macropores: large pores containing a significant amount of air; water passes through them very easily due to gravity.
Micropores: tiny pores that retain water—the primary source of water absorbed by plants.
The combination of macropores and micropores in the soil is known as porosity, which depends entirely on the soil’s composition.
Sandy soils consist mainly of macropores, allowing water to drain easily.
Clay soils consist primarily of micropores, resulting in poor aeration and high water retention.
The soil atmosphere
This refers to the amount of air accumulated within the pores. Ideally, the soil composition should include an air proportion of over 20%.
The air found in the soil facilitates:
- Root respiration.
- Oxidation-reduction processes.
- The decomposition of organic matter.
Gas exchange between the soil and the atmosphere
Soil aeration can be influenced by:
- Wind action, which can force air in or out.
- Soil water displacing air from the pores.
- Gas expansion or contraction due to temperature changes (this can be monitored using subsoil temperature probes).
- Soil texture.
- Root respiration, which consumes O2 while releasing CO2 into the atmosphere.
- Rainfall.
Factors influencing the soil atmosphere
- Texture: if the soil is waterlogged, there is no room for gases. Measurement using moisture sensors and probes is crucial. Aeration is linked to pore size; the smaller the pores, the more water they retain.
- Structure: the arrangement of clay, sand, and silt particles. The more compact the structure, the less air movement is permitted.
- Drainage: the capacity to remove water.
Soil atmosphere issues
Poor soil aeration is caused by:
- Poor irrigation management or excessive rainfall, where water occupies a large portion of the pore space.
- Clay soils that form layers, altering drainage.
- Surface salt crusts that impede aeration; therefore, monitoring salinity using conductivity probes is important.
- Reduced gas diffusion in deeper soil layers due to limited pore space.
Effects of poor subsoil aeration on crops
The negative effects of poor aeration on plant roots stem from both a lack of air and an excess of it.
- Poor aeration results in shorter roots that tend to grow closer to the surface to obtain oxygen.
- High carbon dioxide (CO2) levels reduce cell permeability, disrupting nutrient uptake.
- Highly aerated soils cause minerals to oxidize.
- Waterlogged soils become acidic, and iron levels are reduced.
Labels:
- Sand
- Clay
- Sand
Soil atmosphere
- Plants with roots in the ploughed zone; the remaining soil is very compacted.
- Plants in a stony area. The roots have difficulty developing.
- Sandy and clayey layers. The plant cannot develop its roots.
- Waterlogged layers. The soil needs drainage.
Soil temperature
Soil temperature influences all physical, chemical, and biological processes within the soil. It can alter plant growth and sprouting, and even affect leaf drop.
It influences the decomposition of organic matter. Colder temperatures slow down chemical reactions, whereas warmer temperatures increase erosion. This leads to reduced nutrient availability. In such cases, vegetative cover can help manage these processes.
Subsurface temperature probes are very useful for monitoring plant root activity.
How to improve the soil atmosphere
There are basically two factors that benefit the soil atmosphere:
Drainage via runoff to prevent root suffocation. This can be surface or deep drainage. Regarding irrigation, the best approach is moisture control using probes to avoid waterlogging.
Soil aggregation and tillage. Soil composition plays an important role.
Aeration capacity directly influences oxygen absorption by the roots, O2 exchange with the atmosphere, and the health of the root system.
Plantae: Specialists in soil atmosphere monitoring
As previously mentioned, sensors and probes measuring moisture, soil temperature, and conductivity help us maintain the soil atmosphere in optimal condition. They provide real-time monitoring, preventing waterlogging and allowing for the assessment of root system health based on temperature.
Monitoring is the best way to care for the environment. It saves water and energy while ensuring the plant receives exactly what it needs at all times. It prevents water stress, enabling the farmer to make the most appropriate decisions for each phenological stage of the crop in real time.
Soil atmosphere controlled by moisture, temperature, and conductivity sensors
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