Getting to know your soil

FOLLOWING contributions to Farmers Weekly’s Transition Summit series, where he discussed what makes for successful soil, CHAP’s Dr Andy Evans shares some of his thoughts on the function of this vital ecosystem service provider.

Soil consists of biological, physical and chemical components that collectively provide a medium in which plants can grow, forming a ‘living organism’.

Beyond simply supporting the growth of crops and plants, there are many other functions of healthy soil. One of which is the highly topical carbon storage. Carbon is removed from the atmosphere by plants through photosynthesis, and is stored or ‘fixed’ in plant tissue, roots and soil. This storage process is carbon sequestration.

This is useful to us as humans, because despite carbon being essential for life, drilling and burning fossil fuels releases excess carbon into our atmosphere, beyond that of which can be removed through photosynthesis. This has resulted in an in increase in atmospheric carbon which is attributed to climate change.

So the more we can sequester into soils, the better. This is further enhanced by soils’ ability to recycle crop residues either directly, or through livestock manures. This creates nutrient-rich soil organic matter, high in fixed carbon.

Increasing soil organic matter promotes the growth of new plants, it also improves soil fertility, structure and overall well-being. It improves a soils’ water holding capacity, which has additional benefits for overcoming the effects of drought and extreme weather.

Living organisms

Soil is home to many interacting living organisms, each playing vital roles. From earthworms to the sheer diversity of nematodes, bacteria and fungi, it’s important to encourage the diversity of these organisms.

For one, research has demonstrated a positive correlation between earthworm presence and crop yield. Soil needs more worms! You can do this by reducing tillage, boosting organic matter and minimising the use of synthetic chemistry.

In terms of other organisms, increasing their populations can help to keep pathogens, pests and diseases at bay consequently promoting the long-term health of the soil.

Measurements for benchmarking

Taking regular soil measurements (every few years) is the best way of evaluating how healthy and therefore effective agricultural soils are. It’s important to choose an indexing system and stick to it, to demonstrate real improvements.

A tool to help here is GPS, which supports consistency of sampling, or the smart device application, What3Words. Sampling from the same location again improves the legitimacy of the data you are obtaining, to paint a true picture.

Sampling at a depth of 15-25cm is recommended, as this is where the soil is most ‘active’.

Practical soils advice

Ultimately, farmers know their fields and therefore their soils. If something has changed, be proactive and investigate. Having a greater awareness of the biological, physical and chemical properties will improve the decisions they make for improving and maintaining the long-term health and resilience of their soils.

Dr Evans, an applied crop entomologist/nematologist, recently joined CHAP as Sector Team Lead. To learn more about CHAP’s work in soils, visit our Soil Health Facility page.

Find out more re: the Farmers Weekly’s Transition Summit series, here.

Or if you have any further questions about working with CHAP, please send us an email using the enquiries form at the bottom of our homepage.

Please note, the opinions expressed in this article are the author’s own and do not necessarily reflect the views or opinions of CHAP.