Field history? Just a standard soybean inoculant? Did the seed also have a insecticide and fungicide treatment and if so was it the same on the two plots. I have been using a inoculant because we didn't raise beans for several years. I had a load of seed this year that the inoculant got left off of mistakenly but the fields they got planted on have had two years of beans in a row that were in inoculated.