Amino Acids and Biosynthesis Byproducts As Nitrogen Sources for Corn Production.

Byproducts resulting from the industrial synthesis of amino acids for feed-use might provide a significant supply of nutrients for crop production, particularly nitrogen (N). Iowa has a strong amino acid biosynthesis industry, resulting in a continuous supply of biosynthesis byproducts. Byproduct utilization as an N source for crop production may enhance revenues for amino acid producers and Iowa farmers.  A field experiment was conducted in 2013 near Ames, IA, to evaluate corn (Zea mays L.) response to tryptophan (TRP) and lysine (LYS) biosynthesis byproducts as N sources. The objectives of this study were to determine corn response to isonitrogenous N fertilization treatments: 1) different levels of dry TRP when replacing NH₄-N from ammonium nitrate, and 2) combinations of liquid TRP byproduct with different levels of LYS byproduct. All treatments were adjusted to 196 kg N ha^-1 and arranged in a randomized complete block design with four replicates. Parameters measured included phenological development, leaf chlorophyll, leaf area Index, and normalized difference vegetative index.  Grain yield and quality, and yield components were measured at physiological maturity. On average across all treatments, corn grain yield was 10.14 ± 2.92 Mg ha^-1, stover yield was 8.74 ± 0.25 Mg ha^-1 and harvest index was 0.54. First year results of this study indicate that the TRP and LYS biosynthesis byproducts can replace ammonium nitrate or ammonium sulfate without compromising corn growth and development, grain or stover yield. The field experiment is being repeated in 2014 to confirm the previous year’s results.