Surplus grain is being sold for export.

过剩的谷物正销往国外。

《牛津词典》

We grow just enough food for ourselves to eat, with no surplus grain.

我们收的粮食刚够自己吃，没有余粮。

youdao

Above surplus grain sold to the state, the brigade built up a good grain reserve of its own.

除了卖给国揭的俞粮外，这个刁队还建立了渍己的赂食耽惫。

youdao

When yields are above 90%, Koch takes a third of the surplus grain.

FORBES: Creative destruction 101

And all these things go together because they all arise from the surplus of cereal grain.

NPR: Looking at the World Through Beer Glasses

This week it grew stronger after two Western news agencies reported that farmers would be free to decide what to do with a larger share of their grain surplus, after handing over a quota to the state.

ECONOMIST: North Korea