You may or may not know that 2015 is designated as the year of the soil. The purpose of this is to help us focus it a bit more on the resource that is critical to farmers’ livelihoods and on which all human life depends.

The primary reason for you to think about your soil is because it generates your income. The quality of that land and the condition in which it is kept directly affect its productivity. The quality and general health of soil drives primary plant production for both crop and livestock farming.

Three legs to soil health

Good healthy soil is a three-legged entity which supports the interaction of its physical, chemical and biological properties. All three are equally important for the balance of the soil. Healthy soil supports all kinds of life, as well as the plants which support your income. A healthy soil regenerates its structure, enables water percolation and storage and supports plant and biological life.

Soils take all kinds of abuse. They are degraded by nature as well as man’s activities. While damage is certainly generated by the use of heavy machinery, excessive cultivation, poaching, organic matter loss, etc, our soils are also damaged by natural processes.

Constant rain degrades the natural colloid structure which combines the three basic components of soil – sand, silt and clay.

Good structure sees these three components moulded into little lumps or crumbs (with the help of organic matter) to make good working soils. But when we lose these crumbs, the resulting clay and silt get washed down into the soil to clog up the pore spaces that are essential for water percolation and to enable the soil to breathe.

A good soil needs to be well structured to support plant growth. Soils must contain air and water as well as soil particles. The use of heavy machinery, especially when the soil is damp, acts to squeeze and tighten the soil. Modern heavy machinery, fitted with big tyres, tends to tighten the soil to great depth (in excess of 1m).

Other practices, such as grazing in damp soil conditions, can compact the upper soil layers. This gets worse over time if the damaged soil is not being repaired by nature.

Once soils tighten and the soil pores clog up, water percolation becomes more difficult. We now see many more ponds in fields than was the case years ago because water cannot percolate where it falls. Water running across the surface can carry fine clay with it to rest in areas where ponds form.

Soil porosity

The challenge for farmers is to get these pores opened up again, so that our soils can support maximum levels of growth. Earthworms play a critical role in maintaining healthy soils by consuming the fine soil that is moved down into the soil profile and taking it back to the surface where it is mixed with organic matter to help form humus – a key component of healthy productive soils. The lack of crows and seagulls behind the plough is a sure sign that your soil is not high in biological life.

Soils must be managed to ensure that they support the biological life which helps to reproduce soil structure and recycle nutrients through mineralisation. A healthy soil should have plenty of air pores to enable water percolation, air movement and unimpeded root growth. The presence of humus, generated with the help of biological activity, helps to store water and nutrients to support plant growth.

Soils need earthworm activity but earthworms need food to survive and thrive. Farmers must manage their land in a way that provides organic matter to support earthworms. These then provide the necessary food for other components in the soil’s biological system. Active soil biology helps to repair physical damage to soil structure and makes recycled nutrients available to support plant growth. It is up to each individual to use the most suitable option to provide this food for the biological system.