A scientist testified that run-off from fields spread with poultry manure accounted for a major portion of phosphorus pollution in a sensitive northeastern Oklahoma watershed, reports News OK.

But an attorney for 11 Arkansas poultry companies who do business there argued on 18 November that geochemist, Roger Olsen, overlooked nearly 20 other possible sources of pollution, such as coal-fired power plants, urban run-off and cattle operations.

Mr Olsen, who is testifying as an expert witness in the state of Oklahoma's federal pollution case against the poultry companies, developed his findings after analyzing water and soil samples taken from the Illinois River watershed.

The closely watched case, which began in September and has lagged on for months, wrapped up its 24th day on 18 November.

During his cross-examination, Tyson Foods' attorney, Tom Green, rattled off a list of other possible contaminants he said Olsen left out of his analysis.

Mr Green, who is also representing company subsidiaries Tyson Poultry Inc. and Tyson Chicken Inc., said Mr Olsen had failed to take soil or edge-of-field samples near septic systems, nurseries, golf courses or areas where only commercial fertilizers had been used – suggesting such data might conflict with the state’s premise that excess poultry manure is the major cause of pollution in the Illinois River watershed.

News OK reports that last week, a Cargill executive testified that he had not checked to see if company farmers were following an environmental handbook he helped compile in 2002 that warned them not to spread excess chicken manure on their land because the run-off could pollute area water.

Yesterday, the federal judge scolded the 30 attorneys on Oklahoma's pollution case against the Arkansas poultry industry, accusing them of bombarding him with "thousands" of documents as the bench trial dragged into its 25th day, according to Pine Bluff Commercial.

US District Judge Gregory K. Frizzell, who accused the attorneys of trying to have the documents admitted in order to prepare the case for an appeal. He later candidly admitted that he did not know how he was going to rule on the case.

The two-month-old trial is now almost guaranteed to run until January.