There's a land rush of sorts going on across the nation's most productive farming region, but these buyers don't want to grow crops. They want to plant solar farms.

Developers are flocking to flat farmland near power transmission lines, but agriculture interests, environmental groups and even the state are concerned that there is no official accounting of how much of the region's farmland is being taken out of production.

Planning department records in four of the valley's biggest farming counties show about 100 solar generation plants already proposed on roughly 40,000 acres, or about the equivalent of 470 Disneyland theme parks.

Solar developers have focused on the southern San Joaquin Valley recently for the same reason as farmers: flat expanses of land and an abundance of sunshine. Land that has been tilled typically has fewer problems with endangered species than such places as the Mojave Desert, where an endangered tortoise slowed solar development on federal land.

For more, see: California's rush to go solar threatens farm production