ALBUQUERQUE, N.M. (AP) — New Mexico's two U.S. senators are concerned that tariffs implemented by the Chinese government on dozens of American product lines, including pecans, could hurt growers in the state.

New Mexico is one of the nation's top pecan-producing states.

Sens. Tom Udall and Martin Heinrich wrote a letter Friday urging U.S. Trade Representative Robert Lighthizer to consider the effects restrictive import tariffs on pecans will have on U.S. growers and rural agricultural businesses.

Udall contends increased tariffs are already causing significant uncertainty and will make farming difficult.

China and Hong Kong have been the largest export markets for the U.S. pecan industry.

The senators say New Mexico produced 72 million pounds (32,660 metric tons) in 2016 and that production had a value of more than $213 million.