Amino acids as fertilizer for agronomic crops: The next green revolution?

Abstract

This study sought to determine whether organic N in the form of amino acids could be used as a replacement for synthetic inorganic N fertilizer for growing an agronomic crop, and if so, would there be any agronomic or environmental benefits in doing so. A greenhouse study showed that corn (Zea mays L.) grows equally as well with L-lysine as the only source of N compared to that grown with ammonium nitrate. Positive results were also obtained for L-histidine, but corn did not respond the same to L-alanine or L-arginine. Amino acid profiles for corn grown with ammonium nitrate, L-lysine, and L-histidine were similar. A subsequent field demonstration showed no difference in silage or grain yield between corn grown with liquid L-lysine as N fertilizer in the form commercially produced as animal feed supplement and that of corn grown with urea ammonium nitrate as the N fertilizer. A core lysimeter study showed that the positively charged L-lysine does not leach from soil. Environmental benefits, such as reduced carbon emissions and improved water quality, derived from biosynthetic L-lysine or other amino acid production using N-fixing microorganisms for use as N fertilizer are substantial. This study provides strong incentives for research into alternative means of biosynthesizing L-lysine or other amino acids using N-fixing microorganisms, which might be the next green revolution in agriculture.