The staple crop is rice.

主要农作物为水稻。

《牛津词典》

Tea is the staple crop here.

本地产品以茶叶为大宗。

《新英汉大辞典》

That used to be the staple crop of the islanders.

那以前是岛民的主要作物。

youdao

In the early 1970s, for example, the cassava mealybug, a pale, flat, plant-eating insect, was destroying the staple crop of 200 million Africans.

FORBES: Those Resourceful Bugs

There was plenty of sorghum (the local staple crop) in nearby countries and either buying and shipping it by truck or perhaps even just giving money to starving people and watching the market get food to them would be quicker than anything else that could be done.

FORBES: Famine: Don't Send Food, Send Money

The price of pork - a staple of the Chinese diet - has reached a new high, while crop-growing regions have been hit by severe flooding.

BBC: Chinese inflation hits three-year high