Soils for Sequestration

Improving soils by building soil organic matter is a win, win situation for everyone.

Good soil management is central to sustainable farming everywhere. Healthy soils are any nation’s greatest asset and, if well managed, can go on producing food, fibre and fuel for generation after generation. However much UK farmland is badly degraded, following farming practices that have not looked after the soil, effectively raiding the ‘soil capital bank’.

Fortunately soils have an extraordinary capacity to regenerate quickly and become productive and stable again.

Healthy soils have numerous benefits for the farmer and society:

  • Stable and resilient
  • Resistant to erosion due to stable and improved soil structure. This leads to improved water quality in groundwater and surface waters, and ultimately to increased food security and decreased negative impacts to ecosystems.
  • Easily workable in cultivated systems
  • Good habitat for soil micro-organisms
  • Fertile and good structure
  • Large carbon sinks

Basic Principles to Create Healthy Soils:

Cultivation can reduce soil structure and oxidise carbon, which is then released to the atmosphere. Minimising cultivation frequency and depth alongside ensuring the soil is not too wet when cultivated can reduce the damage arising from incorrect management.

Perennial crops (including grasses) are good for soil because they encourage organic matter formation:

  • Diverse cropping systems (cultivated and grassland) introduce vegetative variety into soils which stimulates soil biology
  • Evaluate machinery operations: minimise depth, frequency and proportion of soil inverted if avoidable
  • Build soil organic matter as much and as frequently as possible!

The Importance of Soil Organic Matter

Healthy soils support a large and diverse microbial community, the interactions between species and niches increases soil functionality to decompose residues and stabilise organic matter. Previously degraded soils that become more sympathetically managed will tend to increase in soil organic matter content at the fastest rates, however, all soils can continue to build organic matter as the depth of high carbon content in the soil increases.

Building soil organic matter is a holy grail for the farmer or grower and is also a win, win situation:

  • Healthy soils produce healthy crops
  • Crops growing in healthy soils give higher yields and higher profits
  • Soils high in organic matter are resilient, stable and have good structure
  • Carbon sequestration rates can be huge

Work completed by the FCT has demonstrated that every hectare of land that raises its soil organic matter levels by just 0.1% (e.g. 4.2% to 4.3%) can sequester approximately 8.9 tonnes of CO2 per year (at 1.4 g/cm3 bulk density). This is an extraordinary figure; in practice that is not only possible but being exceeded by farmers and growers building healthy soils.