> "assuming a baseline application rate of 40 t ha−1 yr−1 of basalt rock dust"

I am sorry, what? 40 tonnes of basalt dust per hectar?? What's hilarious is that when you look up basalt dust on internet, merchants sell it in bags of 2kg, "to be applied 20 grammes/sq meter", while 40t/ha is 4kg per sq meter!