Yes, argicultural technology was absolutely embargoed from China by the West. What world do you live in? The Foreign Assets Control Act was relatively comprehensive and then a year later the "UN" adopted a total collective embargo.
It wasn't embargoed from the USSR. But that was before the Green Revolution anyway. Everyone in the world was heavily subject to crop failures, like the 50% crop failure in the US Dust Bowl in the 30s. It's not like there was a known good recipe to solving famine cycles during the first 2 decades of the Russian revolution.
The idea that Mao was an idiot is neither borne by the evidence nor useful as an explanation. He was clearly effective for long periods of time for highly complex problem spaces. But he made a similar class of mistakes to the mistakes that the USSR did in agriculture. Mistakes that they eventually corrected.