RIVA PALACIO, Mexico — On the edge of a high plain fringed by craggy sandstone hills, Johan Friesen’s small farm is a testament to the rural providence of his Mennonite people.

Neat fields of onion, soybean and yellow corn stretch behind his concrete and adobe house. In the farmyard, a few dozen cows stand in a corral, ready for milking, and a canary-colored reaper awaits repair. But beneath this valley of orderly farms in the center of Chihuahua State, the picture is less than serene, officials and farmers say.

Underground reservoirs have been drained by thirsty crops, like corn, that are the mainstay of the Mennonites’ success, they say. Competition for groundwater — which officials have warned could run out in 20 years — has strained relations between the pacifist, Low German-speaking Mennonites and other farmers and, on occasion, incited violence.

As California guzzles groundwater and Saudi Arabia rents land in Arizona because its own aquifers are depleted, Chihuahua is a study in the costs of overusing a resource and the tensions that flare as it becomes scarce.