South Florida’s sugar growers once again did far better than state law requires in reducing their runoff of harmful phosphorus into the Everglades, water managers announced Tuesday.

Improvements in irrigation and fertilizing practices helped growers cut phosphorus flows by 73 percent, compared to what pollution levels otherwise would have been, water managers said.

The runoff was still more than six times as dirty as most scientists consider safe for the Everglades, where researches say high phosphorus levels have spurred a growth of noxious cattails and killed beneficial brown algae. And the numbers don’t account for phosphorus pollution from other sources, including Lake Okeechobee or western suburbs such as Wellington.

Still, the sharp reductions from the sugar region are encouraging, growers and the South Florida Water Management District said.

"No matter how you look at it, this is good news for the environment," said Judy Sanchez, spokeswoman for United States Sugar Corp.

The sugar region’s runoff contained 53 metric tons of phosphorus from May 2000 to April 2001, the district reported. Had the farmers failed to improve their farming methods, that load would have been 195 metric tons, the district estimated.

The drop in phosphorus had nothing to do with the drought that has parched the farms’ water supplies, said Sharon Trost, head of the district’s Everglades storm-water program. She said the 195-ton estimate took the lack of rainfall into account.

The growers, in western Palm Beach and eastern Hendry counties, must cut their phosphorus by an average of 25 percent under a 1994 state law. Instead, they have averaged 55 percent for the past six years. Farmers have also reduced erosion, minimized fertilizer use and cut the amount of phosphorus-rich soil that drains off their fields.