How to Increase Soil Organic Matter on Your Farm
Introduction
Healthy soil is the foundation of sustainable farming — and soil organic matter plays a central role in maintaining that health. Increasing soil organic matter improves structure, water retention, fertility, and microbial activity, making your farm more productive and resilient.
But what exactly is soil organic matter, and how can you increase it effectively? In this guide, we explain everything you need to know, from definition to practical, farm-tested techniques that will help you build healthier soils for the long term.
What is Soil Organic Matter?
Soil organic matter is the fraction of the soil composed of anything that once lived. This includes decomposed plant and animal residues, roots, microbes, and humus (the stable form of organic matter). It fuels soil biology, enhances nutrient availability, and improves the physical and chemical structure of soil.
In short, soil organic matter is the life force of your soil. The higher the organic matter, the better the soil’s ability to support crops, retain water, and resist erosion.
7 Practical Ways to Increase Soil Organic Matter:
1. Apply Compost and Manure
Adding well-rotted compost or farmyard manure introduces a rich source of organic carbon and nutrients. Regular applications help build soil organic matter and improve overall soil health.
2. Use Cover Crops and Green Manures
Cover crops such as clover, vetch, mustard, and rye protect the soil and add biomass. When incorporated into the soil, they significantly increase soil organic matter while also enhancing nitrogen content and suppressing weeds.
3. Leave Crop Residues in the Field
Rather than removing all post-harvest residues, consider chopping and leaving them on the field. These residues decompose and contribute to soil organic matter while protecting the soil surface.
4. Reduce or Eliminate Tillage
Frequent tilling disrupts soil structure and accelerates the breakdown of organic matter. Reducing tillage helps preserve and gradually build soil organic matter by keeping carbon in the soil and supporting microbial life.
5. Rotate Crops Wisely
Diverse crop rotations, especially those including deep-rooted species and legumes, help maintain and improve soil organic matter by contributing different root structures and residues.
6. Add Mulch and Plant Debris
Applying mulch made from straw, leaves, or wood chips improves moisture retention and gradually increases soil organic matter as it breaks down.
7. Encourage Soil Biology
Soil organisms — from bacteria to earthworms — play a vital role in transforming organic inputs into stable organic matter. Practices like adding compost teas or using biological inoculants can support a thriving soil ecosystem and enhance soil organic matter levels.
Conclusion
Increasing soil organic matter is one of the most effective ways to improve the productivity, sustainability, and resilience of your farm. By applying organic materials, growing cover crops, reducing tillage, and nurturing soil biology, you can regenerate your soil naturally over time.
The results? Better yields, lower input costs, improved water management, and a healthier environment for future generations.
Frequently Asked Questions (FAQs)
1. Why is soil organic matter important?
Soil organic matter improves nutrient availability, water retention, and microbial activity. It also enhances soil structure, helping crops grow more effectively and sustainably.
2. How do I measure soil organic matter?
A professional soil test will measure the percentage of soil organic matter. Most arable soils in the UK contain between 2% and 6%, though higher levels are ideal for sustained fertility.
3. How quickly can I increase soil organic matter?
Building soil organic matter takes time — often years — but consistent application of organic materials and good land management practices will show measurable improvements.
4. Can synthetic fertilisers increase organic matter?
No. Synthetic fertilisers provide nutrients but do not contribute to soil organic matter. In fact, overuse may harm microbial life, reducing the ability of soils to build organic matter naturally.
5. What are signs of low soil organic matter?
Poor water retention, compacted soil, low biological activity, and reduced crop performance may indicate low levels of soil organic matter.
