Only about a quarter of the 6.5 million hectares of corn grown in Mexico are suitable for high-yield production, the other three-quarters of corn land, nearly all rain-fed, has mostly been planted with local criollo varieties.

Farmers of the Santiago Cuauhtlalpan ejido, whose average holding is about four hectares, generally hire out the initial disking of fields in May as the rains start. Only about one in fifty owns a tractor.