No consistently detectable reductions in nutrient pollution are being found in bass fisheries and other waters across the country, despite conservation practices.
That’s the conclusion of a recent U.S. Geological Survey (USGS) study that analyzed 133 large agricultural watersheds associated with conservation tillage and the Conservation Reserve Program (CRP). Researchers discovered no significant improvements in water quality from common practices designed to reduce soil runoff and nutrient loss.
"When you look at it on a large watershed scale, we clearly are not seeing the effects of conservation practices yet," said Lori Sprague, the lead author of the report, which was recently published in the Journal of Environmental Quality.
One possible explanation is that improvements in water quality could lag significantly behind implementation of conservation practices.
"Current nutrient conditions in streams may still be reflecting agricultural practices that were in place prior to the implementation of the conservation practices,” she said.
If improvements do lag the implementation of conservation practices, nutrient levels may be reduced in years beyond the scope of the study. Consequently, the agency plans to continue to monitor watersheds to see if that's the case, Sprague added.
Meanwhile, the Farm Service Agency, which administers the CRP program for the U.S. Department of Agriculture, insists that practices do reduce sediment, nitrogen, and phosphorus runoff.
“At the surface, we know we’ve succeeded,” said spokesman Kent Politsch.
"We can extrapolate that eventually the evidence will show up at the (stream level). It does take time for that evidence to show up."
(This article appeared originally in B.A.S.S. Times.)