Is precision liming the key to better soil health?

The missed opportunity for optimized nutrient efficiency and better soil health.

Precision farming and soil variability

Precision farming is an already established practice that has been used for various applications such as autosteering, fertilization, precision planting, irrigation, and spot spraying. All these applications aim to ease workloads and support farmers with the goal to increase the returns by using resources more efficiently and complying with local legislation.

Multiple sources of information — yield monitoring, remote sensing, weather stations, soil sensors, and soil analysis—are used to track in-field variability. These monitoring tools provide detailed insights of the field conditions, enabling timely adjustments and optimizing management of the crop throughout the season.

One of the main causes of in-field variation is differences in the physical, chemical, and biological properties of the soil. Variations in soil texture, which affect water and nutrient holding capacity, stem primarily from the physical properties of the soil. Chemical and biological properties such as nutrient status, soil pH, and organic matter play an important role in shaping soil structure and determining nutrient availability.

Why managing soil parameters matters

Managing chemical soil parameters effectively is key in precision farming. Despite the availability of Variable Rate Application (VRA) technology which is today widely used for nutrient input planning (e.g., for nitrogen), precision liming is still at an early stage and a great opportunity.

One reason for its low adoption is attributed to the type of lime (Aglime) and how lime is typically applied today. Aglime is mainly applied using specialized liming spreaders, usually owned by subcontractors, farmer associations, or lime suppliers. This creates a barrier for VRA because technology comes at a cost.

Compared to Aglime, granulated lime such as Omya Calciprill provides an ideal opportunity for precision lime applications as it can be applied with ordinary fertilizer spreaders used for VRA fertilizer applications and owned by farmers.

Opportunity for soil pH variable application?

Optimal soil pH is crucial for nutrient availability. A reduction in pH from 6.5 to 6.0 leads to a drop in phosphorus availability by almost 50%. If soil pH drops further to around 5.5, nitrogen and potassium availability is reduced by almost 25%.

Implementing variable liming would help adjust fertilizer application, decreasing production costs and environmental side effects.

Figure 1. Impact of soil pH on nutrient availability.

Current soil sampling practices

The standard practice in soil sampling is taking various samples from a field or dividing the field into sections. These sections are often drawn arbitrarily to balance benefits and analysis costs. As a result, each field or section is represented by a single soil parameter value—an average that may mask significant differences within the field. Depending on the degree of soil variation the calculated average might be acceptable – for low variation acceptable and for high variation not acceptable.

A more sophisticated practice, using modern precision farming software based on yield monitoring or remote sensing, divides the field into different soil zones. These zones can be generated by indicating different yield potential, where soil is the underlying root cause. Soil samples within each zone are pooled and analyzed to adjust management.

recision farming tools also offer the possibility to create an optimal path for efficient soil sampling.

Figure 2. A field map showing distinct soil zones that indicate yield potential, forming the basis for determining soil sampling points and paths.

From analysis to action

Detailed soil surveys reveal how pH varies across a field, influenced by factors such as soil texture, historical management, and organic content. These differences translate into distinct lime requirements for each zone:

Figure 3. A soil pH map reveals significant variability in pH levels across the field.

Areas with low pH need substantially more lime, while areas with pH above 6.5 require only maintenance amounts.

By running an algorithm that calculates lime requirements based on pH and other soil parameters, it is possible to determine the precise application rate for each zone. Some zones may need little or no lime, while others may require higher rates.

The resulting application map can be uploaded to a variable-rate fertilizer spreader, which automatically adjusts granulated lime dosage as it moves from one zone to the next.

Figure 4. Variations in soil pH and texture require different lime rates for proper adjustment, which can be represented in a liming application map.

The benefits of precision liming

Applying precise amounts of lime where it is needed in a highly heterogenous soil will result in better management of fertilizers with potential for saving costs. Current applications are done by applying an average lime rate across a field likely leading to under or over liming especially in highly heterogenous fields.

Figure 5. Illustration showing how a uniform lime application disregards soil pH and field variability, resulting in overliming in some areas and underliming in others.

Choosing the right liming product matters

Omya’s granulated products Omya Calciprill and Omya Magprill are ideally suited for precision liming. They enable farmers to condition soil to its optimal pH while delivering essential Calcium and Magnesium nutrition. This dual benefit supports soil health and promotes vigorous plant growth. Their compatibility with standard fertilizer spreaders makes them a practical choice for implementing variable-rate applications, ensuring efficient resource use and improved crop performance.

Summary – Main Takeaways

Precision liming remains underutilized despite its potential benefits.
Soil pH strongly influences nutrient availability; even small pH drops significantly reduce phosphorus, nitrogen, and potassium uptake.
Traditional soil sampling averages out variability, leading to inefficient lime application.
Zone-based sampling and variable-rate liming allow tailored lime application, improving soil health and resource efficiency.
Implementing precision liming can reduce costs, increase yields, and minimize environmental impact.
Omya’s granulated products enable farmers to adjust soil pH and supply Calcium and Magnesium, while using existing fertilizer spreaders which simplify precision liming.
Omya’s granulated products enable farmers to adjust soil pH and supply Calcium and Magnesium, while using existing fertilizer spreaders which simplify precision liming

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