When it comes to the role of calcium carbonate in soils, its benefits stretch far beyond simply correcting pH, says Omya’s David McLellan.
And although a neutral pH is recognised as a cornerstone of soil health affecting nutrient availability, structure and biology, calcium has many other core attributes which shouldn’t be downplayed, he adds.
“Calcium is essential for both soil health and plant nutrition. From a plant-perspective, it’s an essential element found in the cell walls and membranes of all living creatures. This provides the cell strength and resilience required to help resist pest and disease pressure, among other advantages such as improved root development and NUE.
“As well as improving soil health and biology, studies have shown that if all agricultural land was at a neutral pH we could reduce nitrous oxide emissions by more than 15%; agriculture accounts for 70% of nitrous oxide emissions in the UK,” explains David.
Conversely, a calcium deficiency on top of very wet conditions can cause a range of internal and external issues in crops which lead to restricted growth and yields, he says. “This will be particularly prevalent this season given the difficult conditions growers have faced as heavy rainfall contributes to the acidity of soils.”
Challenging conditions
As a result of the inclement weather, many soils will be depleted of calcium and other nutrients which have leached or been lost to run-off. In some cases, soils may be anaerobic following the waterlogging or compacted as a result of ground-travel in sub-optimum conditions.
“For those with heavy soils, calcium ions help to bind clay particles together with organic matter to form aggregates – this flocculation creates vital pore spaces. With better soil structure comes improved water and air circulation, root exploration and reduced run-off to provide an improved environment for soil biota,” adds David.
However, plants require a continuous supply of calcium throughout the growing season because unlike other nutrients, calcium isn’t particularly mobile and the finer the particle size, the more available it is to the plants.
Calcium applications
According to David, there are several ways of adding calcium depending on the soil pH. “For acidic soils, or crops which prefer alkaline conditions, granulated calcium carbonate such as Omya Calciprill is ideal.
“Calciprill is made from micronised calcium carbonate and the granules dissolve rapidly in soil moisture allowing the carbonate ions to neutralise the hydrogen ions in the soil that cause acidity. The calcium ions then replace the hydrogen ions on the soil colloids and are readily available for the plant to use,” he explains.
“Furthermore, Calciprill can be applied using standard spreader equipment when convenient so contractors aren’t required.”
A mitigating effect
By keeping on top of calcium levels in soils through products like Calciprill, David believes it’s a means of preparing for adversity. “We have to see improvements in soil health across the UK, for healthy crops but also to help compensate for the extreme weather conditions which seem to be occurring more frequently.
“Healthy, well-structured soils are better positioned to recover from these weather extremes and help mitigate risk for growers,” he concludes.
Read more about Omya’s Calciprill in this online exclusive story.
