The University of Georgia Agricultural & Environmental Services Laboratories developed the Fertilizer Calculator for figuring the amount of fertilizer to get. It is based on the test results you get from the lab after submitting a soil sample. The Fertilizer Calculator was developed “to assist users whose fertilizer needs require adjustment from the standard soil test recommendation due to a change in units, availability of fertilizer products, and/or a difference in land size. Fertilizer costs can also be calculated.” To access the Fertilizer Calculator, click here.
Another good source of information on fertilizers is the UT Extension publication PB1637 – Fertilizers and Their Use. This publication will help you understand soil chemical properties which is important because soil chemical properties affect nutrient availability to plants. Soil amendments (lime and fertilizers) contain essential plant nutrients or can favorably alter the soil chemical properties to enhance plant nutrition. This publication discusses essential plant nutrients, nutrient deficiency symptoms, amending soil through fertilizer use and application methods.