Organic Matter – Agriculture Dictionary

Organic Matter: The Lifeblood of Soil Health

Definition:

Organic matter refers to the decomposed remains of plant and animal materials found in the soil, including plant residues, animal manures, compost, and microbial biomass. Organic matter plays a vital role in soil health and fertility by supplying nutrients, improving soil structure, retaining moisture, and supporting diverse microbial communities.

Importance of Organic Matter:

Organic matter is essential for maintaining soil health and supporting sustainable agriculture for several reasons:

1. Nutrient Supply: Organic matter serves as a reservoir of essential nutrients, such as nitrogen, phosphorus, potassium, and micronutrients, which are gradually released to plants as they decompose. This nutrient recycling process helps to sustain plant growth and productivity over time.
2. Soil Structure Improvement: Organic matter improves soil structure by binding soil particles together into stable aggregates, creating pore spaces for air and water movement, and reducing soil compaction. This enhances soil aeration, water infiltration, and root penetration, promoting healthy plant growth and root development.
3. Moisture Retention: Organic matter acts like a sponge, holding moisture in the soil and reducing water loss through evaporation. This helps to maintain soil moisture levels, especially during dry periods, and reduces the frequency of irrigation needed to sustain plant growth.
4. Microbial Activity: Organic matter provides a source of energy and food for soil microorganisms, such as bacteria, fungi, and earthworms, which play critical roles in nutrient cycling, organic matter decomposition, and soil fertility. Healthy soil microbial communities contribute to disease suppression, nutrient availability, and overall soil ecosystem functioning.

Sources of Organic Matter:

Organic matter can be derived from various sources, including:

• Plant Residues: Crop residues, cover crops, and mulches contribute organic matter to the soil as they decompose.
• Animal Manures: Livestock manures, such as cow, horse, poultry, and composted manures, are rich sources of organic matter and nutrients.
• Compost: Composting organic materials, such as kitchen scraps, yard waste, and agricultural residues, produces a nutrient-rich soil amendment that improves soil health and fertility.
• Green Manures: Cover crops grown specifically to add organic matter and nutrients to the soil through biomass incorporation.
• Organic Amendments: Materials like biochar, humic acid, and organic fertilizers can be applied to the soil to increase organic matter content and improve soil fertility.

Management Practices to Enhance Organic Matter:

To enhance organic matter levels in soil and promote soil health, farmers and gardeners can adopt the following management practices:

• Crop Rotation: Rotate diverse crops with different root systems and residue characteristics to increase organic matter inputs and nutrient cycling.
• Cover Cropping: Plant cover crops during fallow periods or between cash crops to add biomass, suppress weeds, and improve soil structure.
• Reduced Tillage: Minimize soil disturbance through reduced tillage or no-till practices to preserve soil organic matter and enhance soil structure.
• Organic Amendments: Apply organic materials such as compost, manures, and biochar to increase organic matter content and improve soil fertility.
• Nutrient Management: Optimize nutrient management practices to balance nutrient inputs and outputs, minimize nutrient losses, and promote efficient nutrient cycling in the soil.

Conclusion:

In conclusion, organic matter is a fundamental component of soil health and fertility, playing a critical role in sustaining plant growth, supporting soil ecosystem functioning, and promoting agricultural sustainability. By recognizing the importance of organic matter and implementing practices to enhance its abundance and quality in the soil, farmers and gardeners can foster resilient, productive, and environmentally friendly agricultural systems.

References:

1. United States Department of Agriculture. (2020). Organic Matter. https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/soils/health/om/
2. Soil Health Institute. (n.d.). Soil Organic Matter. https://soilhealthinstitute.org/wp-content/uploads/2018/09/SHI-Soil-Organic-Matter-Primer-2018.pdf
3. University of California Agriculture and Natural Resources. (n.d.). Organic Matter in Soils. https://ucanr.edu/sites/soils/Soils_and_Plant_Nutrients/Soil_Organic_Matter/

Originally posted 2008-08-28 06:14:37.