China is #1 in ammonia (fertilizer precursor) production with 48 million tons.You will be amazed at how many people on Twitter that thinks America can starve china and that America will suffer no harm from stop trading with china.
Total global ammonia production is 150 million tons.
50% of human biomass derives from Haber Bosch process ammonia. If China cuts off chemical exports the entire world starves. China is only 18% global population but 30% global ammonia production.
And if you cut China, you also cut Russia. Russia is another 10%. They're playing chicken with humanity's food supply if they think they can cut China.