Organic matter

Definition

Organic matter refers to the carbon-based compounds that are derived from the decay of plant and animal materials. This includes a wide variety of substances such as dead leaves, decomposed organisms, and other biological materials that contribute to soil fertility and nutrient cycling. Organic matter plays a crucial role in maintaining ecosystem health by supporting microbial activity and enhancing soil structure.

5 Must Know Facts For Your Next Test

1. Organic matter is essential for soil health as it improves soil structure, water retention, and nutrient availability for plants.
2. The decomposition of organic matter is a key process in nutrient cycling, as it releases nutrients back into the soil that can be utilized by plants.
3. Microorganisms such as bacteria and fungi are primarily responsible for breaking down organic matter, which enhances biodiversity in the soil ecosystem.
4. Organic matter serves as a carbon sink, helping to sequester carbon dioxide from the atmosphere, thus playing a role in climate regulation.
5. The amount of organic matter in soil can vary significantly based on land use practices, vegetation types, and environmental conditions.

Review Questions

• How does organic matter contribute to soil health and fertility?
  • Organic matter contributes to soil health by improving soil structure, enhancing moisture retention, and increasing nutrient availability for plants. It serves as a habitat for microorganisms that play essential roles in nutrient cycling. Furthermore, organic matter helps to prevent erosion and supports the overall biodiversity within the soil ecosystem, which is vital for maintaining fertile land.
• Discuss the role of decomposition in the context of organic matter and nutrient cycling.
  • Decomposition is a critical process that breaks down organic matter into simpler compounds, returning essential nutrients to the soil. This process involves microorganisms such as bacteria and fungi, which facilitate the transformation of dead plant and animal material into humus. The release of nutrients during decomposition supports plant growth and contributes to the overall health of ecosystems by maintaining nutrient cycling.
• Evaluate the impact of land use changes on the levels of organic matter in soils and its broader environmental implications.
  • Land use changes, such as deforestation or intensive agriculture, can significantly reduce the levels of organic matter in soils. This reduction can lead to decreased soil fertility, reduced water retention capacity, and increased erosion rates. The decline in organic matter not only affects plant growth but also has broader environmental implications, such as increased greenhouse gas emissions due to loss of carbon sequestration capacity. Sustainable land management practices are crucial for restoring organic matter levels and maintaining ecosystem health.

Related terms

decomposition: The process by which organic matter breaks down into simpler organic or inorganic compounds, often facilitated by microorganisms.

humus: The stable, dark organic material in soil that results from the decomposition of plant and animal matter, playing a vital role in soil fertility.

nutrient cycling: The movement and exchange of organic and inorganic matter back into the production of living matter, encompassing processes like decomposition and mineralization.