A study by the European Commission’s Joint Research Centre enables us to compute the weight of Belgium. They say …
“water erodes 970 million tonnes of soil every year in the EU. This would mean a one metre-depth loss of soil from an area corresponding to the size of the city of Berlin, or a one centimetre loss from an area twice the size of Belgium. “
So, if 1 centimetre of soil covering 2 x Belgium weighs 970 million tonnes then the weight of Belgium (the top centimetre only!) is 485 million tonnes.
Actually the JRC figures don’t quite add up as they imply that Belgium is 50 times the size of Berlin. Belgium is 30,524 sq km, whereas Berlin is 892 sq km so the ratio is not 50:1 but 34:1. This means that 1 meter of soil over Berlin would in fact cover three times the size of Belgium, not twice the size (assuming 1cm depth of soil).