MELVILLE - Long Island farmers say proposed legislation to limit the amount of fertilizers in groundwater could hurt the local farming industry.

The bill would limit the use of nitrogen, a vital ingredient in many fertilizers farmers use, to levels they consider too strict.

Vegetable farmer Bob Nolan says he and many colleagues have been cutting back on fertilizer use for years. He says they are always exploring more environmentally friendly ways to grow their crops.

“We're pro-active, we don't need a bill to be mandatory,” said Nolan. “The farmers are doing it on a voluntary basis and we've been very successful.”

Adrienne Esposito, of the group Citizens Campaign for the Environment, says new measures have to be put in place to prevent contamination of Long Island's water supply.

Sponsors of the bill say they want to get the input of farmers and others who would be affected before they introduce it in the state Legislature.

Suffolk is the leading agriculture county in the state in terms of the dollar value of crops produced.