Cuba had rich, fertile soil, but due to growing monoculture crops coffee and sugar during its colonial period, its soil was depleted of nutrients. In the interwar period Cuba was an exporter of sugar, but during WWII the US started growing/producing its own sugar, which made prices of sugar plummet. After the revolution the Soviet Union donated a bunch of industrial farm equipment and fertiliser, but all of that equipment is old and useless now. The embargo ensured that Cuba couldn't import any new equipment.

Cuba has been trying to develop cooperative farms for a while now, but without industrial farm equipment it is hard to grow food at scale. I'm not sure if they're able to import fertiliser from Russia, but even that can only get you so far.

Edit: gonna link the book here also, for visibility. Not strictly about Cuba, but it talks about colonialism and exploitation of "Latin America". https://library.uniteddiversity.coop/More_Books_and_Reports/Open_Veins_of_Latin_America.pdf