Two PFI members have carried out trials of soil amendments in the general category of “biologicals” (Table 4.). They don’t happen to be research cooperators, but it hasn’t held them back. John and Rosie Wurpts, Ogden, submitted a proposal to the PFI Sustainable Projects program to investigate the effectiveness of a fertility program consisting of products from Agrienergy, Inc. They compared this package to ISU Extension fertilizer recommendations. In 1992 there was no yield difference, and the cost of the Agrienergy inputs was $34.89 per acre greater than conventional recommendations in corn and $41.69 greater in soybeans. Their study will continue.
Mike Hermanson, Story City, has been using replicated plots to evaluate an Agrienergy program for three years. He never encountered a yield difference between the alternative fertility package and the conventional approach. ISU recommendations, in fact, called for just a nitrogen application in corn years. In year three of his study, Mike added an herbicide band to the conventional treatment, but the Agrienergy program was still more costly by $34.88 per acre.