On one level, clearly, a drought is just bad luck, the savage will of the gods. If it doesn’t rain for long enough, then every farming system grinds to a halt. But the severity of how drought affects a place is shaped by how it has been managed before. And the fact is that a lot of British farmland is now being farmed so efficiently — in monocultures, and fed with synthetic nutrients — that often it has quite low levels of soil organic matter. Now, this can work fine in years where there is plenty of moisture. But over time, we also know that degraded soils dry out quicker in droughts.
The Rothamstead Institute estimates that every 1% increase in soil organic carbon raises the soil’s water holding capacity by about 354,000 liters per hectare: enough to fill five swimming pools. It isn’t how much rain falls from the sky, in other words, but how much we can hold in our soils that really matters.
Systems, in short, can be too efficient; fields need some buffer, some untapped potential, that they can call on in periods of stress and exhaustion. But our farming systems are being asked to run flat-out all the time. There is no slack, and very little resilience. The basic problem is that the economics of agriculture don’t pay for soil organic matter, or for farmers to rotate crops, or to let land have periods of recovery. In practice, that means that most of our arable landscapes are now poorly adapted for extreme weather events.