This year has, by any standard, been an extremely difficult year, but it has brought into focus a need for a serious look at soil health as part of on ongoing business strategy.

In addition to the disruption and uncertainty caused by Covid-19 and EU discussions, weather conditions have been particularly changeable, especially in the first half of the year.

Following a particularly wet winter, we abruptly entered a spell of acute drought from March to April. In Scotland, only 31% of average rainfall levels were recorded in April, making it the third driest April since 1862 and the sunniest since 1929, which did affect grass growing.

“Farmers will have had their grass yields impacted due to these conditions,” pointed out Philip Cosgrave, a grassland agronomist at Yara. “It is, therefore, important for each farmer to have a general idea of their productivity.

"A one-size-fits-all approach can only help to a certain extent. We need to look closely at soil management and fertility in order to determine which fields didn’t perform as well, and then action a plan to resolve any issues.”

Soil health

What does this entail? Mr Cosgrave said that farmers should look at their fields individually to identify particular concerns at the first instance. Is the field producing what it should and, if not, why not?

The weather has certainly had an effect, but in what way? For example, if the land is waterlogged for a period of time then some of the productive grass may have died off or generated a proliferation of weeds.

“We need to look back and ask ourselves the right questions,” he added. “Were the issues that arose due primarily to the poor weather conditions, or were some other factors in play?”

The key to recognising underlying issues is soil analysis. Without a reasonably up to date soil analysis, problems can go undetected and undermine results, said Mr Cosgrave.

If a field had certain problems identified by soil analysis within the last few years, it could still be an issue. Certain factors like suboptimal pH or nutrient status can intensify over time, meaning grass will not perform as well and more productive species can potentially die out.

“It’s important to base our actions on knowledge,” he said. “The recommendation is to perform soil analysis every four or five years, but if there’s a recurring issue in a particular field it might be worth having another test even sooner. A lot can change in just a year.”

As he pointed out, guides and tools such as the SRUC technical notes exist to help farmers generate an NMP (Nutrient Management Plan) specific to their farm, but it’s important to then plan a course of action based on that knowledge.

Doing so gives scope to either save money by reducing nutrient inputs or, if required, pinpoint which nutrients are lacking in particular. The right products can then be invested in and used to build up soil fertility.

“Soil fertility and overall health is the foundation for everything,” added Mr Cosgrave. “Without getting the basics right, achieving stronger results just won’t be possible and inhospitable conditions like we’ve seen this year will wreak even more damage.”

Sustainability and productivity

All purchased nutrients have some form of environmental impact, whether in their production, manufacture or application.

“Many producers of nutrients are trying to lower their carbon footprint and get nutrients from manufacturers to the farm as sustainably as possible,” said Mr Cosgrave. “Collaborative efforts from manufacturers and farmers can make a positive impact, both environmentally and in terms of results.

"Sustainability and productivity go hand in hand. Practical actions, including soil testing and working out the crop’s requirements and what’s needed exactly, to avoid either the over or under application of nutrients.”

For example, nitrogen should not be applied before grass starts growing in the spring, or risks being lost. The holistic effect of other nutrients should also be considered. Phosphate, vital for soil fertility and necessary for strong grass growth, is necessary to derive full efficiency from any applied N.

“If phosphate levels aren’t right, then phosphate will limit growth,” he pointed out. “This then results in poor nitrogen use efficiency.”

By checking that soil P and K fertility is adequate, grass supply will not be limited. Then, more grass grown per kg of N will help minimise losses to the environment.

The same was true with soil pH. If this is not at the optimum level, then nutrient use efficiency will be compromised. The type of N we use also effects crop yields and its loss. We can maximise yield and minimise these losses by using nitrate based N products.

“We need to maximise the value of our nutrients,” added Mr Cosgrave. “By establishing the nutrient contribution from organic manures, we can then calculate accurately what mineral fertiliser is required to grow a first or second silage crop for instance. Growing more crop for every unit of N applied lowers environmental losses and lowers the cost of growing that crop.”

Looking forward

" don’t know what 2021 will bring, but establishing a strong foundation can help any farm remain resilient in the face of often difficult external circumstances. Key to this is understanding the situation on the farm and putting a plan in place.

“Soil fertility is the baseline for all growth,” he added. “Every step you can take – whether it’s performing a fresh analysis, ensuring adequate nutrient supply, or establishing sustainable practices – all works together. For the strongest start to 2021 possible, look to your soil and what it requires.”