Tuesday, November 14, 2006

Zinc Fertilization Effects on Annual Bluegrass.

Elizabeth Guertal1, Robert Walker2, William Dunnivant2, and Bradford Young2. (1) Auburn Univ.-Agron.& Soils Dep, 202 Funchess Hall, Auburn University, AL 36849-5412, (2) Auburn University, Agronomy and Soils Department, Auburn, AL 36849-5412

Although zinc (Zn) fertilization has been evaluated on annual bluegrass (Poa annua L. var. annua), such work usually focused on agronomic yield components such as clipping yield or shoot production.  Possible negative effects of Zn fertilization on annual bluegrass may be a positive, as applied Zn might reduce annual bluegrass germination and growth.  The objective of this research was to evaluate rates of Zn and Zn sources, determining their effect on germination and emergence of annual bluegrass seedlings.  Multiple laboratory and greenhouse experiments were peformed using rates of Zn at 0 to 320 ppm, with Zn sources of zinc oxide and zinc sulfate.  In the greenhouse, hydroponic germination tests showed that germination of annual bluegrass seedlings decreased as Zn rate increased, with average germination rates of 5 to 10% at Zn rates between 80 and 320 ppm.  At every rate of Zn application zinc sulfate was more effective in reducing germination than zinc oxide, largely a function of the increased water solubility of zinc sufalte, as compared to zinc oxide.