The term ‘soil health’ is used widely within the arable industry, but what does it mean and how can it be measured? Abby Kellett reports.
While most farmers understand the need to improve soil health, the ambiguous nature of the term leaves its meaning open to debate.
At this year’s Groundswell No-till Show and Conference, held at Weston Park Farms, Hertfordshire, scientists, farmers and researchers attempted to define the term and debated ways soil health indicators could be used to inform future agricultural policy.
While some claim they can determine the health of their soil by simply smelling it, others favour a more complex approach which takes into account factors such as organic matter levels, the presence of biology and its ability to support crop production with few inputs.
So what indicators should the industry be using to define soil health and can they be used by Government to reward farmers for taking measures to improve soil post-Brexit?
Tony Reynolds, farmer and chairman of Conservation Agriculture UK, said: “It is well recognised soil is our industry’s most important asset and, collectively, we need to improve the value of this asset. Government has suggested farmers are going to be rewarded for taking measures to improve soil health in the future, but every field is different, so getting a parameter which takes account of all that variation will be extremely difficult.
“I believe farmers will receive a standard payment, which will be reduced if they don’t take certain measures to protect and improve their soils. What those measures may be is, at the moment, unclear.”
According to host farmer John Cherry, there are three basic principles farmers should follow to achieve a healthy soil: minimal disturbance, keeping soil covered at all times with living or dead plant matter, and growing a diverse range of crops.
In adopting this approach at Weston Park Farms, Mr Cherry has reduced his input spend. “After a year or two of no-till, we discovered we needed less fertiliser and our pesticide bill had dropped. It is clear to me the old intensive chemical way of farming is failing as more inputs are being required while yields have plateaued,” he said.
Likewise, Cambridgeshire farmer David Walston suggested a healthy soil is one which can deliver strong yields with no inputs. He said: “The term soil health is largely useless – it is a woolly concept and getting something useful out of it is pretty difficult.
“However, to me it is about being able to produce a good crop with no inputs at all. Creating these kinds of soils is going to better for the bank balance of the farmer and better for the environment – so it is a win-win if we can get it right.
“But it is important whatever metric Government may use going forward, it has to correlate to yield.”
However others disagreed, with one audience member claiming ‘yield is just one service which soil provides’.
Dr Ademir Calegari, a consultant for the Food and Agriculture Organisation of the United Nations and the World Bank, believes there are three soil health indicators which can be adopted worldwide: soil carbon, earthworm populations and mycorrhizal fungi.
“In Brazil, farmers are also introducing another soil health parameter, soil respiration, which could be used as an indicator of soil health.”
The CO2-burst test is one method which can be used to measure the amount of biological respiration in the soil, but it is not without its flaws, according to independent plant and soil health educator, Joel Williams.
He said: “One negative is it does not tell us exactly what is respiring – is it the fungi, the bacteria or the protozoa? Typically, fungi-dominated soils are more healthy than bacteria-dominated ones and this test does not take that into consideration.
“While there is clearly a need to provide simple ways of measuring soil health, I think we are in danger of trying to over simplify a complex system which we still know little about.”
Mr Reynolds showed concern the early adopters of conservation agriculture may be at a disadvantage should the Government use current soil health measures as a baseline, which farmers will be rewarded for improving.
“Because all soil types have different characteristics, you cannot expect a sandy soil to have the same organic matter content of a clay soil. We have to find a way of measuring the amount farmers are able to improve their soil over a number of years.
“But because some farmers practicing conservation agriculture have been taking steps to better their soils for many years, their degree of improvement is likely to be less. It would be unfair if this meant they received less support from Government.”
A new series of practical videos to help farmers understand and improve soil health were launched at the Groundswell Show.
Working in partnership with Innovation for Agriculture and Ernest Cook Trust, the Catchment Sensitive Farming team have produced a series of ‘Learning from the Land’ videos.
The videos highlight the importance of soil health and include practical techniques to help improve the overall health of soils in the UK.
The series features episodes on:
To view the videos visit: goo.gl/Vcujz3