A republican legislator says Iowa must establish some limits on the application of certain farm chemicals. Senator Merlin Bartz, a republican from Grafton, is chairman of the Senate Natural Resources Committee. Bartz, who is a farmer, says it’s time for per-acre limits on the application of nitrogen and other heavy metals. He says if Iowa doesn’t do, the feds will eventually establish the rule. Bartz says there’s a need to limit the amount of liquid manure which can be applied on farmland.Representative Bill Witt, a democrat from Waterloo, is a former president of the Iowa Sierra Club, and he agrees with Bartz. He says they have to address the issue of how much phosphorus is going into the soil.Both legislators concede, though, the legislature will adjourn for the year without taking action on the issue. Farmers apply nitrogen and phosphorus or lime to their fields to enhance plant growth.