The average value of Iowa farmland has dropped 2.7 percent over the last year, according to a survey of specialists in farm and land sales, management, development and appraisal. Values varied by crop reporting district, with a 3 percent increase in the southeast and a 2.8 percent decrease in the north-central district since September, according to the Realtors Land Institute. Farmland values are being affected by a limited amount of land on the market, government payments, the new farm bill and higher than expected crop yields in some locations, according to a release. Negative factors include trade uncertainty, decreasing levels of working capital and slightly higher interest rates.