The flowing waterway in this corn field north of Aurora on Thursday morning shows evidence of the 1.5 inches of rain that fell overnight as reported at the airport. That was in addition to the estimated 2 inches of precipitation received earlier in the week. Researchers say it’s not how much rain that fell on an acre of farm ground that counts as much as how much of it was retained by the soil. Studies show that healthy soil practices can increase corn yields by up to 25 bushels per acre.