State the meaning of cation exchange capacity and outline four ways in which it sustains soil fertility?
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Jul 9
Cation exchange capacity (CEC) is a measure of the soil's ability to hold and exchange positively charged ions (cations) such as calcium, magnesium, potassium, and sodium. It is an important indicator of soil fertility as it determines the soil's ability to retain and supply essential nutrients to plants.
Four ways in which cation exchange capacity sustains soil fertility are:
1. Nutrient retention: Soils with high CEC can hold onto essential nutrients such as calcium, magnesium, and potassium, preventing them from leaching away with water. This ensures that these nutrients are available for plant uptake, promoting healthy growth and development.
2. Nutrient availability: The exchange of cations on the soil particles allows plants to access nutrients more easily. As plants release hydrogen ions into the soil, they can exchange them for other cations on the soil particles, making essential nutrients more available for plant uptake.
3. pH buffering: Soils with high CEC have the ability to resist changes in pH, known as pH buffering capacity. This is important for maintaining optimal pH levels for plant growth, as many nutrients are only available to plants within a specific pH range.
4. Soil structure: CEC is closely related to soil structure, as the exchange of cations helps to bind soil particles together, improving soil aggregation and stability. This enhances water infiltration, root penetration, and air circulation in the soil, creating a more favorable environment for plant growth.
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Google Gemini AI
Jul 9
Meaning of Cation Exchange Capacity (CEC):
CEC is a measure of the soil's ability to hold and exchange positively charged ions (cations) on its surface. It represents the total amount of exchangeable cations that can be held by soil particles in a given volume.
Ways in Which CEC Sustains Soil Fertility:
1. Nutrient Retention: CEC helps to retain essential plant nutrients, such as calcium, magnesium, potassium, and ammonium, in the soil. These cations are held on the negative surfaces of soil particles and are released gradually as needed by plants.
2. Buffering Soil Acidity: CEC plays a crucial role in buffering soil acidity. When the soil becomes acidic, hydrogen ions (H+) are released from CEC and replace other cations, such as calcium and magnesium. This process neutralizes the soil and maintains a favorable pH range for plant growth.
3. Improved Soil Structure: CEC helps to stabilize soil aggregates and improve soil structure. The presence of exchangeable cations on soil particles attracts water molecules, which aids in soil aggregation and reduces erosion. Stable soil aggregates create a favorable environment for root development and water infiltration.
4. Microbial Activity: CEC provides a medium for microbial growth and activity. The surfaces of soil particles, where CEC occurs, are often rich in organic matter and nutrients, which support a diverse microbial community. Microbes play vital roles in nutrient cycling, disease suppression, and organic matter decomposition, contributing to overall soil fertility.