Globally, there is a challenging nexus between our need for food security, our ability to maintain energy supplies, whilst protecting our water resources. This challenge is heightened by a rapidly rising population, declining water resources, both in terms of quantity and quality, plus the need to maintain energy supplies. We need, of course, to supply the growing populations with affordable and healthy diets.

Soil is the thin, porous, and fertile medium covering the terrestrial globe that is the hub of this nexus. Soil is the world’s largest water filter. Soil is where the pressures are first felt. And soil is where there will be opportunities to develop sustainable food production whilst ensuring environmental protection. Inevitably, there are environmental impacts and trade-offs. The natural capital stocks of our soils, waters, and biodiversity need to be maintained for future generations to ensure they deliver valuable ecosystem services under growing pressures.

After 50 years of research into soils, water, and food production, I reflect on the challenges we face as soil scientists. I first look back and I ponder how the Chinese managed to be ‘farmers for forty centuries’ on the same soil. Their practices can provide valuable insights for today’s farmers. I show how we have used modern X-ray tomographic procedures to unravel the soil secrets that can lead to this sustainability metric of forty centuries.