Biosolids Impact On Corn Plant Hormone and N Metabolism Associated with Drought Tolerance.

Biosolids have been associated with increased drought tolerance, but the underlying mechanisms have not been well documented. This study investigated the effects of biosolids on hormone and N metabolism associated with drought tolerance in corn (Zea mays L.) under both conventional tillage (CT) and no-tillage (NT) practices on an Orangeburg loamy sand (Fine-loamy, kaolinitic, thermic Typic Kandiudults). The effects of agronomic N rate applications of lime-stabilized and anaerobically digested biosolids were compared with four rates of N on corn leaf hormonal and N metabolites.  The two biosolids at a 1.0x N rate increased photochemical efficiency, indole-3-acetic acid, t-zeatin riboside, soluble proteins, and proline as measured at silking and 20 days before and after silking. The two biosolids also increased leaf total amino acids content as measured 20 days before silking, and antioxidant superoxide dismutase activity at silking.  The results suggest that corn grown in a sandy soil amended with biosolids improved corn photochemical efficiency, growth hormone levels, and N metabolism which was associated with greater drought tolerance and grain yield.