Concrete

The site was an airfield during the 2nd World War and the foundations were never properly cleared.  The evidence lies strewn across the fields and footpaths.  This contributes to the lack of PH balance in the soil, and contributes to poor drainage, resulting in the impaired growth and yield of the wheat harvest each year. Soil takes many years to regenerate. This site is open, windy, and with very little hedging, thus the natural build up of humus takes even longer.

Very active and sustained soil management would be needed to redress the balance.

https://www.theguardian.com/environment/2021/jun/04/soils-great-pressure-un-pollution-report-food-farming-mining