LEAF MINERAL NUTRIENT CONCENTRATIONS OR MEDIA PH AFFECT GEORGIA JET SWEET-POTATO TRANSPLANT NUMBER, LENGTH, AND WEIGHT

The results of four experiments were combined to determine the relatio nships between leaf mineral nutrients or media pH and sweetpotato tran splant production. The relative number of transplants and the relative mean transplant lengths or weights were determined by comparing the v alues obtained with unamended aged pine sawdust, a traditional medium. These values were regressed against leaf mineral concentrations and m edia pH. There was no relationship between relative transplant product ion and leaf nitrogen (N), potassium (K), or manganese (Mn) concentrat ions. Compared to sufficiency ranges for nearly mature sweetpotatoes, concentrations of N and K were low and Mn was sufficient. An upper val ue of 1210 mg/L leaf iron (Fe) was obtained for relative mean transpla nt weight, but concentrations of this mineral were not associated with relative transplant numbers or relative mean transplant lengths. Leaf calcium (Ca) and magnesium (Mg) concentrations were related to all th ree transplant characteristics directly, or indirectly through possibl e effects on leaf phosphorus (P) concentration or media pH. Compared t o the established sufficiency ranges for nearly mature sweetpotato pla nts, Ca and Mg concentrations were low, P and Fe concentrations were s ufficient, and zinc (Zn) concentrations were high.