Soil is the basic building-block of agriculture and a farmer’s most important asset says Adam Henson.
Good soil isn’t just what arable crops grow in; it’s also vital to the health and size of the yield, it cuts flooding, minimises disease, encourages wildlife, safeguards the environment, reduces run-off into local rivers and helps tackle pollution.
What are the different types of soil?
All soil is made up of minerals and organic material and can be classified into six main groups; sandy, silty, peaty, loam, clay and chalk.
Sandy soil
Sandy soils are easy to turn and dig but they don’t retain water, fertiliser or nutrients very well. Farmers in sandy soil areas tend to grow rye, barley, vegetables and root crops such as sugar beet and carrots.
Silt
Silt is often found in river estuaries with the fine particles washed downstream, so silty soil can be among the most fertile of growing environments. It drains more effectively than sandy soil too and it’s suitable for most crops.
Loam
Some agronomists (soil scientists) consider loam to be the perfect farming soil. Made up of 40% silt, 40% sand and 20% clay, loam drains well but retains moisture and is packed with nutrients, so it’s good news for all types of arable and vegetable farmers.
Heavy soil
Heavy soil usually means clay, which can clog into a heavy mass when it becomes wet, making it difficult for air, water and plant roots to move through it. But when it’s too dry, it forms rock-hard clumps. Adding organic matter keeps the clay particles apart, creating space for air and water, and helping wheat, beans and grass to thrive.
Chalky soil
Anyone who farms in the south east of England will know that chalk is a solid, soft rock that dries out easily and is always very alkaline. Although chalky soil is fertile, the high alkaline level prevents plants absorbing iron. You can recognise it immediately from the white stones and flints in the soil. Not brilliant for arable farmers, chalky soil makes for good winter pasture, grazing and forestry.
Peat soil
Peaty soil is stoneless, rich in plant foods and great for roots to take hold. But it can be an acidic soil, requiring a lot of looking after. Existing soil can be converted to a peat type by adding organic matter and decaying vegetation to help improve the soil structure. It’s suitable for growing vegetables, potatoes and wheat.
Acidic peaty soil in moorland areas such as Exmoor isn’t good enough for most commercial crops but it can provide excellent rough grazing and woodland.
