The federal Clean Water Act will soon, if it has not already, impact agriculture from California to Maine.

In California, farmers are going through the throes of meeting water quality runoff standards. In other states, nutrient management plants are or will soon be required. Under the new conservation title of the farm bill, growers can be rewarded for writing and adopting best management plans.

At the recent Beltwide Cotton Conferences in New Orleans, a panel of growers and experts were obviously aware of the latest regulatory edict to face farmers; keeping nutrients and soil out of the “waters of the United States” as dictated by the Clean Water Act.

For some that will mean building around field dikes or grassy buffer zone to contain possible unwanted runoff.

For others it was changing management practices to be safe rather than sorry.

J.C. Banks, Oklahoma Extension cotton specialist, said nitrogen recommendations have been changed to mitigate any problems.

Where Extension once recommended applying the estimated amount of nitrogen needed preplant, after a soil analysis to determine residual N, Banks said growers are now advised to apply half the crops estimated need preplant with the remainder in season and possibly foliar N based on petiole sampling.

Others indicated that the newly developed precision ag technology featuring GPS directed grid sampling, aerial imaging and variable rate application technology should go a long way toward preventing nitrogen from getting to waterways.

Grid sampling, imagery

Bill Weir, University of California Merced County Farm Advisor emeritus, reported on the use of grid sampling and aerial imagery at Bowles Farming near Dos Palos, Calif., to better manage nutrient inputs.

It is being used to identify fertilizer zones in fields for variable application rates of sulfur, zinc, gypsum and potash and plans are to use it to determine nitrogen rates as well.

Bowles utilizes soil sampling and petiole sampling to gauge nitrogen needs. He also relies on mapping fields using spreadsheets.

Yield monitors, another element of precision agriculture, are telling growers more about their crop to improve management.

“It has taken us four years to figure out how to use yield monitors,” said Alabama cotton producer Shep Morris.

“They are telling us cotton waist high yields more than cotton shoulder high,” he said. That information is translated into a look at nitrogen use and other nutrient management programs.

e-mail: hcline@primediabusiness.com