Understanding Soil Fertility: The Foundation of Productive and Sustainable Crop Management

Soil fertility is the cornerstone of successful agricultural production. It determines a field’s capacity to supply essential nutrients required for optimal crop and grass growth. Fertility levels can vary significantly between fields due to differences in soil type, historical management practices and cropping rotations. Understanding this variation is critical for making informed management decisions and achieving optimal production.

Assessing Soil Fertility through Sampling

Soil sampling provides an accurate and objective assessment of a field’s fertility status. By analysing representative samples from each field, farmers can determine nutrient availability, organic matter content, and pH balance. This information forms the basis for creating a tailored crop nutrition plan, ensuring that nutrient applications meet crop requirements, avoiding excess and deficiency.

An effective soil sampling programme will enable producers to:

• Optimise fertiliser use efficiency.
• Match nutrient inputs to crop demand.
• Protect the environment through responsible nutrient management.
• Maximise economic returns from fertiliser investment.

The Role of Soil pH in Nutrient Availability

Among soil fertility parameters, pH is one of the most influential. Soil pH directly affects the chemical availability of nutrients and the biological processes responsible for nutrient cycling.

The optimum pH range varies slightly by crop type:

• Grassland: 6.3
• Cereal crops: 6.5

When soil pH drops below these levels, nutrient availability is significantly reduced. At pH 5.5, only 77% of nitrogen, 48% of phosphorus and 77% of potassium applied are accessible to the plant. Even at pH 6.0, nutrient losses remain substantial.

With the cost of 20-10-10 fertiliser predicted to reach approximately £450 per tonne in spring 2026, reduced nutrient efficiency at pH 5.5 could result in financial losses of up to £149 per tonne of fertiliser applied. At pH 6.0, potential losses remain high at around £90 per tonne. These figures illustrate the direct economic value of maintaining soils within their optimum pH range through appropriate lime applications.

Precision Soil Sampling and Nutrient Planning

To address these challenges, Fane Valley offers a precision soil sampling service designed to provide accurate and representative results for each field. Samples are collected systematically, giving confidence in the resulting fertility assessment.

Once analysed, the Fane Valley Team will interpret the data and can prepare a comprehensive nutrient management plan. The  nutrient plan includes:

• Field-specific liming recommendations.
• Consideration of available organic manures.
• Selection of the most cost-effective fertiliser products.
• Guidance on environmentally sustainable nutrient applications.

The result is an integrated, evidence-based approach that helps maximise crop performance, maintain soil fertility, and meet environmental and legislative requirements.

Conclusion

Regular soil testing and pH management are essential components of modern, sustainable crop production. Understanding and addressing soil fertility variation across the farm, enables farmers to enhance productivity, protect environmental resources, and secure the best economic return on fertiliser investment.

To learn more about Fane Valley’s Soil Analysis Service, contact your local store, local agronomist or call 028 9261 0485.