What is healthy soil?
If you have ever done any gardening or farming you will have a sense of what a good soil structure is, or perhaps an understanding of a fertile soil, but what do we really mean when we talk about soil HEALTH. Even the professionals don't have a single definition though this one from the FAO is pretty good: "the continued capacity of soil to function as a vital living system, within ecosystem and land-use boundaries, to sustain biological productivity, promote the quality of air and water environments, and maintain plant, animal, and human health".
It’s not news to most growers that improving soil health can reduce inputs, increase resilience and improve yields, but how do you know if you have healthy soil and what should you do to improve it? Margins for growers are not getting any bigger, and most are having to push their systems hard just to stand still and survive. Investing in future health might seem like an unaffordable luxury. Some progressive growers are spending time and money to maximise their soil health in the belief that a failure to do so could lead to an inability to produce in the future.
One of the surest ways of improving your soil health is to increase soil organic matter. Adding organic matter will change the amount of nitrogen and other nutrients in soil, though it’s not easy to predict exactly how much of which nutrient is available to plants at any one time, and it will depend heavily on the type and maturity of the material. Adding organic matter will also improve soil structure and the diversity and number of soil organisms. Soil with good structure has lots of stable aggregates which helps heavy soils to drain and light soils to hold onto water. So a healthy soil, full of life and well managed, is better able to cope with the kind of extreme weather events we are seeing more and more frequently.
Much of the innovation in farming comes from farmers themselves, so the GREAT Soils team (funded by AHDB horticulture) is building a network of growers and advisors to learn from and support each other to improve the health of UK horticultural soils. We have recently carried out a review of different ways you can assess your soil health. Some are very simple - dig a hole with a spade and take a good look. Others involve expensive testing in biological labs. All of these methods can tell you something about your soil, but you have to use the results to inform your crop and soil management decisions if you are to make any test worthwhile. The growers in our initial groups helped give some guidance on which tests they consider to be worth doing, and we’ve summarised the results in a simple table. Which method you choose to use will depend on your situation, inclination and budget!
We’re keen to hear from any farmers or growers with experience of trying to manage and measure soil health - please get in touch with us if you would like to share what you’ve found with others.