A popular country singer is back in Iowa today to attend a rally for a farm activist group. Willie Nelson went on the road to Iowa in 1997 to hold a concert and attend a rally for the Iowa Citizens for Community Improvement. The rally at the National Pork Producers Council headquarters in Clive called for a repeal of the mandatory pork checkoff promotion fund. I-C-C-I spokesman Erick Davidson says Nelson is back in Iowa to encourage producers to vote to end the fund.I-C-C-I contends the money paid into checkoff is primarily being used to promote huge corporate operations — leaving small producers out in the cold.Nelson will hold a concert at the Val Air Ballroom in West Des Moines and then hold a news conference to talk about the checkoff. The checkoff will go to a vote yet this year, but a date hasn’t been set.