Desertification is not just caused by lack of precipitation (aridity). It can also be the result of soil degradation. Scientists in the USA have discovered that crop farming across the US prairies has caused a serious loss of the bacteria that hold the soil ecosystem together. Their research compared cultivated land with the rare pockets of ancient tall prarie grass which have never been cultivated, for example in cemeteries or sites reserved for special scientific study. They found that certain bacteria were missing from the tilled soil.
Soil microbes play a key role in maintaining soil fertility (Box 1). Their loss has been masked by continually adding fertilisers to the soil to improve crop growth. This has created a false sense of security. Once the top soil passes a crucial threshold of microbe loss its recovery rate plunges.
Your organisation does not have access to this article.
Sign up today to give your students the edge they need to achieve their best grades with subject expertise
Subscribe
