Romney, appearing in Van Meter, a small town west of Des Moines, said President Obama wants to raise both the income tax rate for those in the upper brackets and the estate tax, calling it a "death tax."
"He's planning on raising the death tax pretty significantly," Romney said. "My own view is, we ought to kill the death tax. You paid for that farm once. You shouldn't have to pay for it again."
Romney also accused Obama of doing little to help agricultural exports.
"Now, the president and I have different records when it comes -- and viewpoints when it comes to exports," he said. "You recognize that about a million jobs in this country are associated with agricultural exports. And over the last four years, the president has signed no new trade agreements with any nation around the world. Even as China and European nations have put together some 44 different agreements, he's done none."
The Obama countered that charge, which has been made before, Monday. Spokeswoman Jen Psaki told reporters aboard Air Force One: "That is not only absurd, it's inaccurate. He's basing it on an absurd premise that President Bush signed a couple of trade agreements, but the fact remains that the president renegotiated the trade agreements -- made them better for American workers, made them better for the American auto industry and the American meat industry -- and that's why we not only got them through Congress, but the president actually signed them into law."