What is the number one food crop that isn’t harvested by combines?

Vanilla

Explanation:

Sometimes that manual labor shows up in the price of the food; sometimes it doesn't ... We thought there would be an easy answer to that, but there isn't. ... This spice is among the most expensive in the world; the biggest producers are Italy, Iran and Spain ... Those forces combine to lead to the labor issues.

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

here's your answer.