The claim Aust "dumps" barley on China is wholly without merit under relevant WTO rules. If China applies duties to Aust barley, it will be a pure act of political retribution. And will shutter a $1.5 bil industry. https://www.abc.net.au/news/2020-05-10/coronavirus-china-australia-trade-tension-barley-tariff/12232426

According to WTO disciplines,"dumping" means deliberately selling goods abroad below the cost you would sell them at home. (1) Doing this would be stupid for Australian barley farmers (why would you forego revenue in a drought?!); and (2) it just isn't happening anyway.

As for the claim Aus drought relief is an "actionable subsidy"? 1st, that's a pretty dog act China. 2nd, an actionable susbidy requires demonstration of injury (per WTO SCM agreement). But as Aus barley doesn't displace local producers (China a net importer), where's the injury?