Sir, – The most important factors in determining (not just ‘helping’), global food supplies (ref: The SF, May 14), are two-fold – a), farmers; and b); the soil.

They are really one-and-the same thing now as they have been since the first farmers 10,000 years ago!

Ever thus, all of us farmers and growers of livestock and plants (including arable), farm soil. Healthy soils with robust stocks of organic matter are essential to current and long-term food supplies and to withstanding the battering coming from our changing climate.

Innovation in plant breeding, with genetic engineering, is not going to make one jot of difference to soil health, let alone global food supplies. But farmers can independently and immediately start making more of a difference by working with what is under their feet through soil management and aspiring to exemplary soil health.

The degradation of once healthy soils, due to loss of soil organic matter, compaction etc leading to erosion of top soils, costs Scotland millions each year including diminishing productivity. Cultivatable soils in the UK have lost 40-60% of soil organic carbon. A massive 52% (and counting), of soils globally are degraded directly affecting carbon cycles, water cycles in addition to global food supplies.

We farmers have the solution ... and it's beneath our feet.

Denise Walton. Peelham, Foulden, Berwickshire.