Soil Composition


Soil structure and fertility are essential to healthy crop establishment and development. Not only does soil act as a growing medium and supports plant roots, it regulates water and air supply, provides nutrients and is home to a multitude of interdependent organisms which can improve soil health and aid plant growth.

As well as its mineral components (a combination of silt, sand and clay), soil is typically composed of organic matter, air and water which fill the small pores between the mineral particles and are vitally important for a healthy plant development.

Plant roots and soil organisms need oxygen to respire and good aeration is thus an essential ingredient of healthy soil. Limited oxygen availability restricts the respiratory process and creates anaerobic conditions which hamper root development and encourage the growth of anaerobic bacteria responsible for denitrification.

Plants absorb water though their root system and fully rely on it for growth and access to nutrients such as nitrates, phosphorus, potassium and soluble sulphate. Excess water, however, can damage plant roots and good soil structure is key to ensuring unrestricted water supply and circulation.

Healthy soil requires a sufficient proportion of both water and air: low moisture content makes nutrient uptake difficult resulting in plant stress, whereas poor aeration leads to the development of anaerobic conditions, restricting the reproduction of beneficial soil organisms.

Regularly assessing soil condition should therefore be a vital part of any farming programme. Identified issues such as compaction or erosion should be addressed. Implementing a farming regime that supports the soil’s natural structure, such as reduced tillage, will help to restore its condition and in time will result in healthier, better yielding crops. Strip tillage system which promotes the retention of straw and previous crop residue on the surface will help conserve moisture and reduce erosion, as well as provide organic matter to be recycled into nutrients thus aiding plant development.