The Sino-Soviet rift/split is a complicated issue. But there can be little doubt that it was complete by mid 1963, when the «Polemics on the General Line» were released by the Chinese Communist Party.
However, From Lorentz M. Lüthi‘s book «The Sino-Soviet Split» I gained the following understanding of the hefty grain aids that the Russians (shortly before the complete split) agreed to deliver to China - but Semaphore‘s comment says that the first three are actually the same!
- 1961 Feb. Need for emergency grain purchases, volume unclear [Lüthi, 199]
- 1961 Feb. Khrushchev offered 1 million tons of grain and 500,000 tons of Cuban sugar on a loan basis. China agreed to use the sugar loan and asked to keep the grain offer in reserve. The PRC however used part of the offer soon after [Lüthi, 200]
- 1961? Mar. In late March, Zhou also approached the Soviets with a request to deliver on loan another 300,000 tons of grain [ibid]
- 1962: the Soviet government agreed to deliver 350,000 tons (grain) immediately in exchange for the delivery of 150,000 tons of rice later in the year.49 With this, Soviet food aid ended [ibid]
Does anyone know if or when these were payed back?
For some of them, I noticed, Lüthi states they were granted, but that doesn’t mean they were received!
("Yet all this was inadequate. On an inspection tour to the northeast, Zhou found that the area was so short of grain that he finally accepted an offer of 200,000 tons from the Soviet Far East to feed China's northeast. It was later repaid with imported grain."), and I believe she cited a Chinese source for this sentence.