State officials are issuing an advisory this week to farmers and others who use propane: buy it now. Ward Lenz is a fuel market analyst for the Iowa Department of Natural Resources.Lenz says propane prices have risen just like gasoline prices have. Lenz says Iowans should either buy their propane now, or buy it on contract to be delivered later.Propane is selling for about 85 cents per gallon today. Last year, it was selling for 30-cents less, per gallon.Farmers use propane to run the dryers on their corn and bean bins and some Iowans, primarily those in rural areas of the state, use propane to heat their homes. Most Iowans now use natural gas to heat their homes.