Landscape-Scale Evaluation of a Humic Product in An Iowa Corn Region.

A humic product extracted from lignite was evaluated in 2009 for its benefit to corn (Zea mays L.) production in central Iowa.  One application rate was compared at different crop growth stages at a research station and in three farmers’ fields.  At the research station, the product appeared to improve aboveground crop biomass and root length in early to mid-season, to extents that were affected by timing of product application, previous crop (corn versus soybean), and soil fertility. Variability among field replicates was considerable.  Increased crop biomass with early season application of the product was also evident in two of the three farmers’ fields.  Increases were often by 10-15% but were in cases greater.  The third field had mistakenly received close to 220 kg N ha-1 as fertilizer.  Effects of the humic product on grain yield will be discussed.  Results will also be discussed for an early-season application of the product in test strips on several tens of farms across Iowa.