Topic

Weather

Weatherwatch: Saharan dust drops microorganisms into European soil

Scientists are examining how ‘blood rain’ affects soil microbiome, with Portuguese vineyards a particular focus Dust events, when thousands of tonnes of fine sand whipped up from the Sahara are dumped over Europe, are becoming more intense. These sometimes produce “blood rain” that leaves visible red streaks, and while generally harmless, the dust is not sterile but brings a freight of microorganisms. One big concern is how imported microbes may affect the soil microbiome and impact agricultural fertility and crop yield. Southern Portugal lies along one of the main deposition routes for Sahara

18 Sept 2026, 14:06 UTC

Weather

Weatherwatch: soil moisture deficit – how dry are the UK’s thirsty soils?

SMD is the moisture the soil must make up until it is at capacity, with very dry conditions over most of England and Wales When the ground is thoroughly wet, after excess rainwater has run off it is said to be at field capacity. Meteorologists describe drought in terms of soil moisture deficit (SMD) from field capacity. The SMD is a measure of how thirsty the soil is, expressed as how many millimetres of rain it would take to top it up to field capacity. In southern England, the SMD tends to hover around zero in winter when fields are wet. In summer it may be about 100mm, going up to 150mm or

18 Sept 2026, 11:05 UTC