What is the significance of organic matter percentage in soil?

• A. It affects nutrient availability and soil structure.
• B. It only changes color
• C. It has no impact on fertility
• D. It determines drainage only

Answer: (A)

Organic matter percentage is important because it directly influences two key aspects of soil that affect fertility and crop growth: nutrient availability and soil structure. As organic matter increases, the soil’s capacity to hold and exchange nutrients improves through a higher cation exchange capacity, and nutrients are released more slowly as the material decomposes, providing a steady supply to plants. Microbial activity thrives with more organic matter, helping to mineralize nutrients and support a healthy soil ecosystem.

Physically, organic matter helps bind soil particles into stable aggregates, which creates better pore spaces for air and water movement. This tilth enhances root penetration, improves water infiltration, increases water-holding capacity, and reduces crusting and erosion. In practical terms for fertilizer management, soils with higher organic matter tend to retain nutrients longer, reducing losses from leaching and runoff, while low organic matter soils are more prone to nutrient losses and poorer structure.

So, the percentage of organic matter is significant because it shapes both how nutrients are stored and made available and how the soil physically supports root growth and water movement.