Farmer Focus: Soil health review shows weaknesses to work on
Dafydd Parry Jones © Richard Stanton During autumn 2021, we had our soil tested again. Normally, we test every three years to check what’s going on below the surface, where it all begins.
This year we went a step further and tested more than the usual pH, phosphate and potassium.
We investigated soil biology, organic matter, soil structure, texture classification, earthworm numbers and species, carbon content and microbial activity.
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See also: New soil test gives more detailed measure of organic matter
Yes, this might seem like an information overload for a sheep farmer. But occasionally it’s good to know whether we are on the right track, so we can manage the livestock accordingly.
I was inspired to do this after reading a few Nuffield reports about soil a few years ago.
The pH of our soils was very satisfactory owing to recent lime application, and ranged from 6.2 to 6.8.
But our phosphorus and potash levels were below target, and we have certainly found the area we need to invest in during the next few years.
The soil biology was mainly on target, except for a very low copper and a high iron content. This is attributed to the natural geology of the area.
The ratio of low copper to high molybdenum could be of concern, as this could induce further copper deficiency in the livestock.
Organic matter was mainly very good, ranging from 10% to 17%, and total organic carbon ranged from 4% to 7%.
Historically, we used the rule of thumb of spreading phosphate every four years and lime every 10 years.
As a result of recent continuous monitoring, we know we have nearly 20 years before we need to lime again. But maybe the use of soft rock phosphate and its slight liming ability has attributed to that.
We’ve identified that 5t/ha (2t/acre) of ground lime can increase the pH from 5.8 to 6.3 within two years.
In the past we used a great deal of magnesium lime, and our levels of magnesium were extremely high. Having moved away from this product 10 years ago, our levels have fallen in line with targets.
We were fortunate to have our soil testing fully funded by the Farming Connect advisory service. We worked as a group of farmers who came together to investigate the issues on our individual farms.